eChapters

Abstract

The Remote Sensing and the followed up field based investigations show that the Tamil Nadu coast, India, is facing series of geoenvironmental problems due to tectonic movements and morphodynamic processes. Such problems pose a challenge to the engineering geologists. The paper discusses such challenging engineering geological problems and plausible remedial measures.

INTRODUCTION

Molecular tools generally refer to molecular genetic tools. Although the first use of these tools began more than four decades ago, whenLewontin & Hubby (1966) used allozymes to find out the amount of genetic variation present in wild populations of Drosophila, the lack of expertise and high cost of these tools have prevented their widespread use among ecologists in general and behavioural ecologists in particular. But recently the accessibility and costs of these techniques have come down a lot and with the right kind of collaboration, lack of expertise is no longer an issue.

As was mentioned above, the Lewontin & Hubby’s (1966) investigation was done using allozymes. Although still an option, user-friendly neutral nucleotide markers are more preferred by investigators nowadays. The discovery of the polymerase chain reaction (PCR) in 1983 by Kary Mullis was the single landmark in this field, if one has to mention one. The use of molecular markers has totally revolutionized the field of ecology. It has provided ecologists the tool to ask questions, which were hitherto impossible to tackle and also to answer questions with much more precision and accuracy than was possible till now. It has toppled long held beliefs, sometimes, romantic ones, by ecologists.

Introduction

Increasing production of cereal crops, oil seed crops, and horticultural crops is becoming more important than ever before owing to increasing population and changing food habits of the people. The modern tools of biotechnology are being exploited to the fullest throughout the world for developing transgenic crop plants with improved traits. Already about 20 countries in the world are growing transgenic crops, predominately with traits such herbicide tolerance and resistance to insect-pests. However, there is a constant fear of pollen flow from theses transgenics to the neighbouring non-transgenic fields or to their weedy or wild relatives. It has become a matter of great concern to all biotechnologists to develop alternative strategies to prevent the pollen flow.

The best alternative strategy available today to circumvent the nuclear- transformation associated bottlenecks in developing tenable crop transgenics is the chloroplast transformation technology. This technology allows introduction and insertion of foreign genes into the chloroplast genome, called plastome. Chloroplasts are the site for photosynthesis in plants mostly present in leaves. In general called plastids, they are also present in other parts of the plant. For example, chromoplasts in coloured leaves and fruits, amyloplasts in starch storing organs, leucoplats in roots, and etioplasts in dark-grown seedlings. The plastids arise from proplastids - the undifferentiated form of plastids present in most plant cells. Just like nucleus, these plastids (and also mitochondria) contain their own genetic material on the chloroplast genome.

ABSTRACT

Commercial propagation using tissue culture techniques started in seventies for orchids in USA. Since then, the science and technology of tissue culture have advanced particularly after the development of the most widely used medium by Murashighe and Skoog (1972). The science has led to the development of the fascinating area of gene transfer. Today, micropropagation protocols are available for almost all horticultural crops. But, there are certain grey areas where research need to be intensified to solve the problems confronting certain difficult to propagate species belonging to plantation and spice sectors. The major area that needs to be addressed is recalcitrance.

ABSTRACT

Microbial contamination is perceived as the most serious threat faced by plant tissue culture research laboratories and commercial production units. A culture is often viewed as contaminated when obvious microbial growth incited by fungi, yeast or bacteria is noticed on the culture medium. On the other hand, there can be situations when microbes may be present in a covert or latent form with serious side effects on the cultures. The present investigations were taken up with the objectives of elucidating the cause of poor growth, lack of regeneration response or modification of rooting observed with visibly clean cultures of different horticultural crops. Apparently clean cultures of grape, banana, watermelon, eggplant, gerbera and chrysanthemum of recent origin or after long-term in vitro culturing were used in this study. Indexing the medium of such cultures using fungal/ yeast and bacteriological media brought out the covert association of one or more bacterial types with varying proportions of incidence in such cultures. Indexing of tissue revealed bacterial presence in different parts of in vitro plantlets. In some instances, bacteria showed endophytic colonization while being not detectable in the tissue culture medium subsequent to a disinfection or antibiotic treatment. Such bacterial association appeared to be the cause of in vitro decline observed with long-term micropropagated cultures, lack of reproducibility of tissue culture protocols, failure of in vitro rooting etc. besides being a threat to in vitro gene banks and germplasm exchange.

ABSTRACT

Recognizing the need to apply plant tissue culture tools for generating planting materials of important spice crops especially vanilla, the Spices Board started Biotech Production Unit at its head quarters building at Kochi with an annual production potential of 8 lakhs plantlets. Complete tissue culture protocols were developed and scaled up for large scale production of vanilla and other spices viz. large cardamom, small cardamom and tree spices. The laboratory is equipped with all modern facilities and is established in an area of about 2000 sft. Department of Biotechnology, Govt. of India also participated in the venture by sanctioning a project entitled “Regional centre for large scale production of tissue culture plantlets of vanilla and other spices” with a financial out lay of Rs 95 lakhs equally shared by DBT, New Delhi and Spices Board, Cochin.

At present there is a stock of over 3.00 lakh vanilla cultures in the lab and already 1.25 lakh plant lets were sent for hardening. The Spices Board, in coll aboration with “Kudumbashree”, a poverty eradication mission of Govt. of Kerala, extend short term training in tissue culture techniques to undergraduates from ‘Below Poverty Line’ (BPL) families and engage them as long term trainees in the Biotech Production Unit. The Board also coordinates and extends support to Kudumbashree members for, establishing and maintaining hardening facilities for TC plantlets thus providing means for empowering women from BPL families.

ABSTRACT

Astudy was undertaken to evaluate the performance of tissue culture derived plants vis a vis open pollinated seedlings of cardamom (Elettaria cardamomum Maton). A total of 102.5 ha (units) covering 50 ha in Kerala, 37.5 ha in Karnataka and 15 ha in Tamil Nadu was selected for the present study out of which each demonstration plot (unit) had an area of one hectare in which 80% of the plants are tissue cultured and 20% are open pollinated. Elite cardamom clones were subjected to in vitro multiplication and their respective open pollinated seedlings were compared. The planting was initiated in 1989 and completed with 1991 in all the zones identified. Plant growth characters such as number of tillers, number of bearing tillers and panicles per clump were recorded and compared. The yield was recorded in 1993-94 and 94-95 seasons after its stabilisation. Results indicated that tissue culture plants performed better compared to open pollinated seedlings with regard to growth attributes and yield irrespective of the seasons and zones. In Kerala region tissue culture plants exhibited a yield increase of 24.3 and 36% over open pollinated seedlings for the 1989 and 1990 plantings respectively. Similar trend was observed in Tamil Nadu for 1989 and 1990 planting where the percentage increase in yield became 130 and 21 respectively. In Kerala, the yield performance of tissue culture plants and open pollinated seedlings was on par during 1990 planting but in the subsequent year (1991) tissue culture plants showed 24% increase in yield compared to their respective open pollinated ones. Further, the study enabled to identify cardamom clones suited to in various zones of the cardamom tract. Accordingly 14 clones with a yield potential of over 750 kg/ha under moderate management were identified and this indicated that cardamom clones are highly location specific in their performance.

ABSTRACT

Vanilla planifolia Andrews - the high value, exotic spice crop has recently gained wide acceptance in the southern and northeastern states of the country. Being an orchid, germination of naked embryo is limited and this favours genetic uniformity. An attempt was made to induce genetic variability in Vanilla through biotechnology tools for its exploitation in crop improvement programmes. In vitro embryo culture and mutagenesis were applied for the purpose. Plantlets were multiplied, hardened, planted out and evaluated for morphological, biochemical and molecular markers. Great interclonal variability was observed in the in vitro derived plantlets. The intraclonal variability was very low in tissue culture derived regenerants. Isozyme and RAPD assay confirmed genotypic variation. Six superior clones were identified and distributed to farmers for further evaluation.

ABSTRACT

Vanilla (Vanilla planifolia Andrews) is a high value spice crop having immense potential for cultivation in India as a source for natural vanillin. Though the crop was introduced way back in 1835, its cultivation gained momentum only in the recent past due to various reasons. Lack of sufficient good quality planting materials is one of the constraints for expanding the area under the crop. Conventionally vanilla is propagated by vine cuttings, but this method is inadequate to have large number of planting materials in a short span of time. So, micropropagation was attempted and proved to be highly successful. In the present study, performance of vanilla plants raised from tissue culture plantlets and vegetative cuttings was assessed on large-scale in planters’ field covering a total area of 111 ha in Kerala(68ha), Karnataka(28ha) and Tamilnadu(15ha) with the financial assistance of the Department of Biotechnology, New Delhi under the project entitled “Tissue culture Vanilla : Product Plan“. Disease free elite accessions of vanilla identified by the Indian Cardamom Research Institute (Spices Board), Myladumpara from its germplasm repository were used as mother plant source for tissue culture multiplication and also for raising the nursery for producing vegetative cuttings. The field planting for the demonstration plots was carried out during 1996-1999 on a cluster approach basis having 400 plants in each unit or plot of 0.25 ha. Accordingly a total of 444 evaluation plots were laid out under the project covering the aforesaid three states. Out of the 400 plants in a plot, 80% were nursery hardened grown up tissue culture plants and the balance( 20% )vegetative cuttings of comparable length. Observations on growth and yield attributes such as vine length, number of leaves per vine, internodal length, number of beans per vine, bean size, yield etc. revealed that performance of tissue culture plants is on par with that of conventional plants raised from vegetative cuttings of comparable length. It is also observed that if good management practices are adopted, tissue culture plants perform better at the full bearing stage of the plant. This proves that tissue culture plants of vanilla can be popularized as a cost effective and faster source of planting materials compared to conventional vegetative cuttings. As the demonstration plots were distributed under varied agroclimatic situations, the influence of different weather parameters on yield was also ascertained. Further, the project could convince the farmers about the comparable performance of tissue culture plants and that is quite evident from the ever increasing request for tissue culture vanilla plants received by the Spices Board.

ABSTRACT

Vitex trifolia L. (Verbenaceae) is known for its medicinal property. Micropropagation can provide the opportunity to obtain large number of homogeneous plants and there are no reports of micropropagation of this species. So, we attempted for in vitro propagation of this species and described here is an efficient and rapid propagation method. This report describes in vitro shoot induction and plant regeneration from mature nodal explants of Vitex trifolia L. on Murashige and Skoog (MS) medium fortified with benzylaminopurine (BAP), kinetin (KN), thidiazuron (TDZ), adenine (ADE), and 2- isopentenyladenine (2 - iP) (0.25-10.0 mM). Multiple shoots differentiated directly without callus mediation within 3 weeks when explants were cultured on medium supplemented with cytokinins. The maximum number of shoots (9 shoots per explant) was developed on a medium supplemented with 5.0 mM BAP. Shoot cultures was established repeatedly by subculturing the original nodal explant on the same medium. Rooting of shoots was achieved on half strength MS medium supplemented with 0.5 mM naphthaleneacetic acid (NAA). Rooted plantlets were transferred to pots containing autoclaved soil and vermiculite mixture (1:1) that showed 90 % survival when transferred to outdoor. Plants transferred to the field have established themselves in the soil and are growing well. The regenerated plants did not show any immediately detectable phenotypic variation. Natural stands of Vitex trifolia are fast disappearing in India because of indiscriminate collection and over exploitation and the outlined procedure here offers a potential system for mass multiplication and conservation of Vitex trifolia.

ABSTRACT

Considering the difficulties faced during ex vitro establishment of orchid plants the present investigation was undertaken to elicit information on the influence of different sucrose levels in the in vitro rooting medium and by subjecting the plants to different levels of triazole at the time of planting out in order to overcome the mortality percentage at the time of ex vitro establishment. Among the growth parameters observed viz. crop growth rate, net assimilation rate, and relative growth rate was found to be high in plants treated with 40 g/l of sucrose concentration and also at the triazole level of 5 mg/l. The photosynthetic rates were observed to increase meanwhile the transpiration rate was declined in plants grown under the above treatment levels of sucrose and triazole. The maximum survival percentage was observed when the in vitro plants grown in rooting medium with 40g/l of sucrose which is attributed to the influence of sucrose concentration on morphological characters studied viz. plant height, number of leaves per shoot and number of roots per shoot. Triazole treatment of plantlets at the time of planting out helped in better survival percentage which is the whole sum effect of increase in number of leaves per shoot, number of roots per shoot of plants grown under the triazole level of 5 mg/l. Where as the height of the plant was inversely proportional to triazole concentration,the biometric aspects studied viz root length, total fresh and dry weight of the plants with the above mentioned treatments were found to be superior. The present study envisages the measures to be taken during in vitro propagation and ex vitro establishment of tissue cultured plants in order to over come the field mortality.

ABSTRACT

Mucuna pruriens (L.) DC. is one of the important medicinal plants that contains L DOPA (L-3,4 dihydroxy phenylalanine) which is the precussor for the neurotransmitter dopamine that plays an important role in curing Parkinson?s disease. To accommodate the huge demand for L DOPA, in vitro production of the drug using cell cultures is felt essential. Hence, an experiment was carried out with completely randomized design with seven treatments viz., T₀ - Control; T₁ - MS + 2 mg l^-1 NAA; T₂ - MS + 2 mg l^-1 IAA; T₃ - MS + 2 mg l^-1 2,4-D; T₄ - MS + 2 mg l^-1 Kinetin; T₅ - MS + 2 mg l^-1 BA; T₆ - MS + 1 mg l^-1 IAA + 1 mg l^-1 BA and 3 replications. Among the various explants investigated stem bits registered the least days (12.38) for callus induction. The stem bits responded well with better callusability (78.57 per cent), relative growth rate (2.57) and callus index (249.16). MS medium + 2 mg l^-1 2,4-D was found to be the best for inducing callus in various explants namely stem bits, leaf bits and root bits. L DOPA accumulation was more in cell suspension cultured in liquid MS medium with 4 per cent sucrose + 1 mg l^-1 IAA + 1 mg l^-1 BA and that was confirmed by means of HPLC.

ABSTRACT

Tamarind, an economically important multipurpose tropical tree, is a species of choice for sustainable development of wasteland due to its hardy nature and adaptability to various agroclimatic conditions. However, there are very few reports on in vitro regeneration of tamarind. In an attempt to induce caulogenic response, effect of different cytokinins on nodal explants from mature trees was tested. The study extended to seedling explants, revealed that 6-Benzylaminopurine (0.08 - 44.39μM) and Zeatin (0.09 - 9.12μM) induced multiple shoots with callusing at the base of explant. Kinetin (0.09 - 9.29μM) and 6-γ,γ- dimethylallylaminopurine (2iP) (0.09-9.84μM) remained ineffective for multiplication of shoots and callusing was noted at the cut end of explant in contact of medium. Thidiazuron (TDZ) (0.09- 9.08μM) failed to induce morphogenic response and triggered dedifferentiation in the basal cut end. This led to profuse callusing in the explant and restricted morphogenesis. To avoid wound in the explant, tamarind seeds were cultured in medium containing TDZ.

Seedlings were germinated in medium with or without Thidiazuron (4.54, 9.08, 13.12, 18.16μM). Differentiation of the apical meristem to shoot was restricted and proliferation of the cotyledonary node meristem was triggered. Large number of meristematic buds appeared in a radial pattern around the node. The meristematic activity subsequently spread towards the cotyledonary bridge and also in the proximal part of the hypocotyl. These buds differentiated to form shoot primordia and subsequently to shoots in medium devoid of growth regulator. Plants developed by micrografting of these shoots on seedling derived rootstocks, survived in soil.

ABSTRACT

It is essential to prospect wild Zingiber species for soft rot resistance, since the cultivated ginger is monotonously susceptible to this disease. We evaluated the genetic diversity of Zingiber species and their response to Pythium aphanidermatum, the causal agent of soft rot. Diversity of 21 cultivars and three wild accessions of Z. officinale, 84 accessions of five wild species: Z. zerumbet, Z. cernuum, Z. neesanum, Z. purpureum and Z. wightianum and one accession of Hedichium flavescens were examined using AFLP markers. No polymorphism was detected at more than 500 AFLP loci screened in ginger cultivars, which to our knowledge, is the most extreme case of genetic narrowness in a species. Analysis revealed high variability in Z. cernuum and relatively low variations in other species. Strong correspondence was evident between the genetic diversity of a species and its mode of propagation. Selected accessions of Zingiber species were inoculated with Pythium zoospores and the disease progression was scored. The response to Pythium varied from total susceptibility in Z. cernuum and Z. officinale to hardy behavior among Z. zerumbet accessions. The present study provided an estimate of genetic diversity of Zingiber species common in Kerala. Species relationships and population genetic structure were discussed. The monotypic nature of ginger cultivars may hinder the possibility of their identification based on their nucleic acid profiles. The present study identified Z. zerumbet as a potential source of soft rot resistance, which will trigger off the application of genomics tools to access this trait in order to genetically engineer soft rot resistance in ginger.

ABSTRACT

India is the largest producer of banana, contributing to 17.3 per cent of the global production. In Kerala, it is the leading fruit crop, being cultivated in an area of 99,412 ha with an annual production of 7,31,650 tonnes. Biodiversity in the cultivars of banana, which consist of triploids, is complex especially in Nendran. Nendran belonging to Musa AAB plantain subgroup is the leading banana cultivar of the Kerala. in Kerala, several landraces are available, cultivated in different parts, known in different local names. Twelve Nendran ecotypes of banana belonging to AAB genomic group were collected from Banana Research Station, Kannara, Banana Nursery Farm, Palode and Instructional Farm, College of Agriculture, Vellayani to ana lyse genetic divergence using RAPD marker and morphological traits. Out of the forty one decamer primers screened for RAPD analysis, 34 could produce amplification. Twenty five primers showed high level of polymorphism. Finally, six of the most promising primers viz., OPA-01, OPA-03, OPA-13, OPB-04, OPB-10 and OPB-12 were used for RAPD analysis. Statistical analysis for the morphological traits and RAPD marker were conducted using the software programme NTSYS pc version 2.02e. The matrix average taxonomical distances (similarity coefficient) among the ecotypes ranged from 0.59 to 1.00 in RAPD profiles and morphological profiles (dissimilarity coefficient) ranged from 2.82 to 11.21. In the dendrogram (RAPD profiles), Koonoor Ethan showed the maximum genetic divergence. Quintal banana and Zanzibar came under a single clusters at a distance of 0.79 and clustered together at a distance of 0.82. Both the ecotypes showed next higher genetic divergence among the Nendran ecotypes. In the case of morphological traits, the same trend could be observed. Koonoor Ethan showed the maximum genetic divergence at a distance of 11.21 and Quintal banana showed next higher genetic divergence at a distance of 9.11. Koonoor Ethan, Quintal banana and Zanzibar were distinct ecotypes among the Nendran ecotypes of Kerala

ABSTRACT

Random Amplified Polymorphic DNA (RAPD) markers were used for characterizing eleven banana (Musa AAB Plantain Subgroup) clones using 40 decamer primers. Eight primers, which produced reproducible banding patterns, yielded 42 scorable bands with an average of 5.25 bands per primer. The amplification products ranged in size from 400 to 1500 bp. A genetic similarity matrix was constructed using the Jaccard’s coeffecient method. The pair wise similarity coefficient values varied between 0.3333 and 0.9355. Based on the coefficients, distances between the clones were computed using SYSTAT software package. In the dendrogram constructed by the nearest neighbour (single- link) method (Krzanowski, 1988), all the eleven clones were found grouped under five clusters. Attu Nendran, Changanasseri Nendran, Changazhikodan, Kaliethan, Koonoor Ethan and Quintal Banana formed the largest cluster. Manjeri Nendran and Myndoli formed the second cluster. Padalamurian, Mysore Ethan and Zanzibar formed three separate clusters. Zanzibar, belonging to the Horn Plantain group was different from the rest of the clones.

ABSTRACT

Genetic relationships were estimated among twenty five ashgourd (Benincasa hispida (Thunb.) Cogn.) landraces of different types using PCR-based random amplified polymorphic DNA (RAPD) markers. The molecular survey of the ashgourd germplasm by RAPD using three random primers resulted in twenty scorable bands (average of 6.66 bands per primer) of which two were monomorphic and rest, 18 were polymorphic (90.0%). Pair-wise genetic similarities among the landraces determined using Jaccard’s coefficient ranged from 0.14 to 1.00. The dendrogram based on clustering matrix separated the landraces with morphologically distinct smooth textured fruits from waxy textured fruits and the former group showed less divergence than the latter. With in the group of waxy textured fruits, limited variation was detected among landraces with small and medium sized fruits. Further, morphologically similar landraces with large fruits form distinct clusters with in the major clusters. The study demonstrated the usefulness of the RAPD marker analysis in effectively assessing the genetic relationship present among the ashgourd landraces examined.

Introduction

Genetic markers have assisted in genomic characterization of various crops species (Rafalski and Tingey, 1993). Most of the genetic marker systems rely upon DNA sequence polymorphisms (Staub et al., 1996). Each system has unique advantages and disadvantages based on cost, experimental objectives and type of information desired. Regardless of its inherent methodology, the effective use of any marker system for genetic analysis requires reliability and consistency.

The random amplified polymorphic DNA i.e. RAPD (Williams et al., 1990) or arbitrarily primed polymerase chain reaction (Welsh and McClelland, 1990) marker identifies DNA sequence polymorphisms. In this technique, segments of genomic DNA are amplified in a polymerase chain reaction i.e. PCR (Mullis et al., 1986) with random primers followed by agarose gel electrophoresis. This is simple, relatively inexpensive and is amenable to high throughput investigation. RAPD markers are usually dominant and polymorphisms are observed as the presence or the absence of DNA bands of a particular size. RAPDs are common molecular approaches employed in plant breeding, genotypic differentiation, gene linkage analysis, assigning evolutionary and taxonomic affinities and relatedness and DNA fingerprinting analysis (Lin et al., 1996).

ABSTRACT

Owing to paucity of available genetic / molecular markers, onion breeding still relies heavily on phenotypic selection methods. DNA markers can provide plant breeders genetic information for indirect selection of plants. All the DNA based procedures require high quality plant genomic DNA. Abundance of polysaccharides and phenolics present in plant tissue often impede PCR amplification. The polysaccharide contaminants can also produce downstream problems by inhibiting many of the enzymes that are employed in subsequent analysis and cloning. RFLP based markers in Allium species pose certain problems due to relatively large size of the genome compared to most other herbaceous crops. As an alternative, RAPD would prove advantageous in genetic analysis of Allium. Here we present our results on optimization of DNA extraction in onion to get amplifiable quality of DNA for further RAPD analysis. Leaf samples were collected from the onion germplasm maintained at Indian Institute of Horticultural Research (IIHR), Bangalore. Dried leaf protocol was suitably modified to obtain fair quality of DNA. After varying each of the ingredients of the extraction buffer we arrived at the optimal extraction buffer, which resulted in good quality DNA. Quality was analyzed by subjecting the DNA to agarose gel electrophoresis and restriction digestion. Extracted genomic DNA was quantified with ‘Hoefer’s Dynaquant’ (Pharmacia, USA). The DNA quantity ranged between 160-2400mg/gm of dried powder. The standardized 25ml PCR mixture contained template DNA (25ng), 5 pmol of primer (Operon Tech. Inc., Alameda), 2mM MgCl₂, I unit of Taq polymerase (Bangalore Genei), with 10x buffer along with 200 mM each of dNTPs. Amplifications were performed in thermal cycler (MJ Research, PTC 100) for 45 cycles after an initial denaturation of 95°C for 3 minutes. In each cycle denaturation for one minute at 95°C, annealing for one minute at 35°C and extension for two minute at 72°C was programmed with final extension step at 72°C for 5 minutes. This fine tuned protocol resulted in clear, informative RAPD profile.

ABSTRACT

The present investigation was undertaken to standardize the DNA extraction methods, to optimize the PCR conditions and generate RAPD’s to study the genetic variability in chrysanthemum. Total genomic DNA was extracted from freshly emerged leaves of chrysanthemum cultivars (Flirt, Nagpur Red, Snow Ball) using different DNA extraction methods (CTAB method, SDS potassium acetate method, SDS miniprep method and urea phenol method). The highest amount of DNA (349μg/g of leaves) was extracted using CTAB method, while it was lowest (130 μg/g of leaves) in SDS miniprep method. The absorbance ratio was high for DNA extracted by CTAB method (1.82) followed by SDS- potassium acetate (1.65) and SDS miniprep (1.60) methods. For standardization of PCR ampl ification conditions, optimization was carried out to determine the optimal concentrations of template DNA, MgCl₂, Taq DNA polymerase and annealing temperature. In general, either no products or products with inconsistent bands were obtained when the concentration of template DNA was 25 ng or MgCl₂ was 1.0 mM with high annealing temperature of 45°C.

ABSTRACT

Though the genetic control of sex determination is being explored in several animal systems, no much information is available on the genetic basis for sex specificities in dioecious or sexually polymorphic plant species. Date palm is a unique member of the family Palmaceae which exhibits dioecy. Here we report the sex-specific variation in the genomic DNA of male and female date palms as revealed from an extensive study conducted with palms representing different date palm growing regions of the Kingdom of Saudi Arabia. The genomic DNA content in females was less than 60 per cent compared to those of the male genotypes. Polymerase chain reactions carried out to amplify different segments of the alcohol dehydrogenase (AdhA) gene from the date palm genomic DNA yielded two DNA fragments each in the female genotypes where as the same primers amplified a single fragment in male plants. Genomic Southern analysis of Eco R1 restriction digests showed RFLP between the male and female genotypes with the male plants showing a single hybridization signal of approximately 14 kb size and the females showing six additional bands of varying molecular weights. The results of our investigations reveal the potential of molecular biology in differentiating the sex in date palm at DNA level. Further research is needed to develop DNA markers that will help to unequivocally identify the sex of dioecious plants at the seedling stage.

ABSTRACT

Piper colubrinum is a wild relative of the cultivated species of black pepper, Piper nigrum. The enzyme hydroxy methyl glutaryl Co A reductase which catalyses mevalonate synthesis, is the key enzyme in isoprenoid biosynthesis.This is the rate limiting step in the pathway which leads to the formation of sesquiterpene phytoalecins, a group of plant defense metabolites. Piper colubrinum is known to be tolerant to the dreaded disease called foot rot, incited by Phytophthora capsici. The hmgr gene is reported to confer resistance to fungal pathogens. Hence we made an attempt to isolate gene encoding this enzyme. cDNA was synthesised by reverse transcription from total RNA of P.colubrinum using oligo dt primers. Specific degenerate primers designed based on the conserved boxes among various plant species were used for amplifying hmgr gene from the cDNA. The 700 bp amplicon was cloned in pGEMT vector and sequenced with T7 primer. Multiple sequence alignment using clustal W 1.8 revealed homology of the cDNA fragment with hmgr genes in several other plant species. Maximum similarity was observed among P. colubrinum, Solanum xanthocarpum and Nicotiana tabacum. The cDNA library of P. colubrinum constructed in lTriplEx2 when screened with radiolabelled hmgr amplicon, yielded positive signals. Attempts are being made to isolate full length gene from these clones, which could be later used for imparting biotic stress tolerance to cultivated crop species.

ABSTRACT

Basic understanding of plant cell proliferation and differentiation is essential for applying modern techniques of genetic transformation. The lack of understanding about the physiological and molecular mechanisms underlying in vitro morphogenesis, together with the non-availability of reliable morphogenetic markers, is one of the most serious constraints for application of gene transfer technology to plant improvement. Plant tissue culture has therefore remained an empirical science. In recent years, concerted efforts are being made to understand the molecular control of cell differentiation. In light of this, present work was carried out to study the role of CKI1 (cytokinin independent 1) gene, one of the genes implicated in shoot regeneration, by transforming the tomato cotyledons through Agrobacterium mediated transformation with two different gene constructs one with CKI 1 gene and another without CKI1 gene. In both the constructs, nptII gene was used as a selectable marker. Transformation of tomato cotyledon explants with CKI 1 gene resulted in higher regeneration of putative transformant s (8.0%) as compared to transformation of explants without CKI1 gene (2.1%). The results show that CKI1 gene has a role in increasing the regeneration frequency in tomato.

ABSTRACT

Astudy was undertaken with the main objective to standardise the Agrobacterium mediated genetic transformation technique in Dendrobium Sonia 17. Protocorms and protocorm like bodies (PLBs) of Dendrobium orchid were transformed by Agrobacterium tumefaciens strains LBA4404 and EHA105 harbouring the plasmids pCAMBIA2301, pCAMBIA1301 and PBI121. The PLBs were generated in vitro by culturing the shoot apices in half strength MS medium. The protocorms were obtained by culturing the seeds in vitro. The sensitivity of orchid tissues to various antibiotics viz., ampicilin, rifampicin, cefotaxime, carbenicillin, kanamycin and hygromycin was evaluated to use the antibiotics as selection agents. The sensitivity was studied in detail by scoring the tissues, based on the morphological changes as those remaining fully green, partially discoloured, bleached, completely turning brown and dead. The various requirements for transformation viz., the type and size of explant, infection time, wounding, co-cultivation and incubation period, concentration of acetosyringone required, elimination of bacteria, and the selection of transformants were optimised to establish a successful transformation system. The pre- cultured explants were mixed thoroughly by gentle swirling with the bacterial cells obtained by centrifuging the bacterial suspension, and also with the bacterial suspension diluted to 1/5 with fresh medium. Then the explants were cocultivated with the bacteria for 2 days at 28°C. The transformation was performed through two consecutive stages of cultivation, the first stage on half strength MS medium containing cefotaxime and subsequent stage on selection medium containing kanamycin. Initially recovered PLBs following co-cultivation, were allowed for further selection with kanamycin. New PLBs and leaves were formed from the transformed PLBs when they were regenerated under kanamycin selection. Successful transformants were obtained with a maximum transformation efficiency of 3.0 per cent with the addition of acetosyringone 100 mM. Out of the kanamycin resistant PLBs 69.23 per cent were GUS positives. The newly formed PLBs and leaves when subjected to histochemical GUS assay indicated successful transformation and it was detected as distinct blue spots on the PLBs after 24’ hours. The PLBs which were not co-cultivated with Agrobacterium were green in colour. The transformation were further confirmed by PCR analysis.

ABSTRACT

Cassava has developed importance mainly as an industrial crop due to its ability to store large quantities of starch (74% to 85% of dry weight) within secondary root structures. Cassava starch is exploited as a source of human food, feed for livestock and as raw material for the food processing and chemical industries. Research accomplishments during the last four decades helped India to have the top position among cassava growing countries with an average yield of 24 t ha-1. However several traits like starch quality, high protein , post harvest deterioration etc can be altered only through the development of transgenics. The present study summarizes the results of the experiments undertaken to optimize the protocol for the development of transgenic cassava through Agrobacterium mediated gene transfer. Friable Embryogenic Callus (FEC) was developed in the cassava var. TMS 60444 us ing Murashige and Skoog (MS) media with picloram (50μM). Experiments were conducted to study the efficiency of different Agrobacterium stains viz, AGL 8, GV3101, C58C1, LBA 4404 and EH105 in transforming FEC. The strains differed in their growth rate. The strains EH105 and AGL were slower in growth as compared to other strains and the protocol was modified accordingly. Among all the strains, EH105 resulted in maximum recovery of transgenic tissues. The paper also summarizes the present status of development of transgenic cassava along with future thrusts.

ABSTRACT

An efficient in vitro micro propagation protocol was developed for direct shoot produc tion of Contoloupe (Cucumis melo variety (NS Abhijit) using cotyledons as explant. The excised cotyledons were cultured on Murashige and Skoog’s medium (MS) contain- ing plant growth regulator, 6 Benzyl adenine with various concentrations for the study of shoot production. The best condition for the shoot production was with 1.2mg/l Benzyl adenine (BA) in MS medium. The shooting frequency was 65% and three shoots were obtained from each explant after 14 days of culture. The shoots (~1.5 cm length) were rooted most effectively on 0.1mg/l of α Naphthalene acetic acid (NAA) supplemented MS medium. We have also standardized the transformation protocol for GUS gene in the muskmelon variety Eden Gem to see test the feasibility of this variety for Agrobacterium mediated transformation. The transformed explants were confirmed through Indigogenic GUS assay.

ABSTRACT

Biofertilizers can supplement the chemical nutrients and helps in reducing the production expenditure in agriculture. Crop biofertilization with microbial consortia is an important strategy to improve the physical, chemical and biological conditions of the soil. The facultative methylotrophs are capable of fixing atmospheric nitrogen, besides it produces phytohormones viz; IAA, GA and cytokinin, vitamin B₁₂, polysaccharides, PHB, and siderophores. The essential nutrients are considered as the most important, among the factors limiting growth and yield of the tomato crop. The application of adequate amount of fertilizers is a pre-requisite for exploiting the genetic potential of tomato variety. Therefore, efficient and economic use of the fertilizer with microbial consortia would help in decreasing the input costs for raising bumper crop.

More number of studies carried out on the effect of facultative methylotrophs in different parts of the world and in India. The results confirmed that the facultative methylotrophs have a greater importance in increasing the growth and yield of various crop plants. Keeping this in view an experiment was conducted to find out the interaction effect of facultative methylotrophs with other bioinoculants viz., Azospirillum, Azotobacter, PSB and VAM (by seedling dip method followed by PPFM phyllosphere spray) on yield of tomato var Ruchi. The results showed that the treatment with above microbial consortia (50.71 t/ha) was found to increase the yield of the tomato crop by 62.73 percent over uninoculated control (18.90 t/ha) and individual treatments.

ABSTRACT

Phytophthora rot is the most destructive disease of black pepper nursery inflicting heavy crop losses. Considering the seriousness of the disease, the present study was undertaken to isolate and select the efficient antagonists from pepper nurseries raised in Government farms at Chelakkara, Pazhayannur, Mannuthy and Pananchery of Thrissur district. A quantitative estimation of the rhizosphere microflora from different nurseries revealed more abundance of soil bacteria followed by fungi and actinomycetes. Based on cultural characters of the rhizosphere microflora, 22 fungi, 20 bacteria and five actinomycetes were selected for further studies. Antagonistic action of soil microflora against Phytophthora capsici was studied by dual culture method in comparison with that of standard culture of T. harzianum. The study revealed that all fungal isolates and five bacterial isolates were antagonistic towards the pathogen with varying degrees. Among the fungal isolates, 13 isolates including T.harzianum recorded cent per cent inhibition of P.capsici. From among the fungal isolates that showed antagonistic reaction in dual culture, further selection of efficient ones was carried out based on the antagonistic index (AI). The isolate 22 F₂ (Trichoderma sp.) showed the maximum AI of 3000 followed by isolate 34 F₂ (Trichoderma sp.) and T. harzianum with an AI of 1500 each. The cultural and morphological characters of the efficient native isolates (22 F₂ and 34 F) were studied and were identified as Trichoderma longibrachiatum Rifai aggr. and Trichoderma viride Pers. ex S.F. Gray aggr. The three antagonists were found parasitic on P.capsici as evidenced by excessive coiling, penetration and disintegration of the hyphae and thereby these Trichoderma spp. used in the study is found to have effective parasitic effect on the pathogen in addition to some degree of antibiosis and these fungi could be utilised for the management of Phytophthora rot in black pepper nursery.

ABSTRACT

Studies on the impact of bio-fertilizers with levels of NPK on bulb yield, dry matter production, nutrient uptake and cost: benefit ratio in onion (cv. Bellary Red) were conducted in medium black soils during kharif and rabi seasons of 1999 and 2000 both under irrigated and rainfed conditions at the Agricultural Research Station, Hiriyur located under Central Dry Zone of Karnataka. The treatments were; T₁-Control, T₂-Azotobacter, T₃-Azotobacter+75% N+PK, T₄-Azotobacter +100%N+PK, T₅-Azospirillum, T₆-Azospirillum+75% N+PK, T₇-Azospirillum+100%N+PK, T₈-VAM, T₉-VAM 75% P+NK, T₁₀- VAM+100%P+NK, T₁₁ ? recommended NPK(125:50:125 kgha-1) and T₁₂-75% recommended NPK. The experiments were laid out in RBD in three replications.

The bio-fertilizers Azospirillum brasilence (500g ha-1) and Azotobacter vinelandii(500g ha-1) were applied to seedlings at transplanting separately by dipping the roots in the slurry for 15 minutes. The VAM fungi - Glomus mossae was applied to soil @ 1 kilogram per square meter area of nursery bed. The recommended dose of FYM @ 25 t ha-1 was applied to all the treatments as basal dose.

The results of the investigations revealed that the plants provided with Azospirillum + 100% N+PK (T₇) produced highest bulb yield (250.29;339.02;232.98 q/ha), highest total dry matter production (7053.96;8992.78;6287.03 kg/ha), maximum uptake of N, P a nd K ( 1 5 7 . 8 8 : 7 3 . 5 6 ; 7 0 . 4 6 N PK k g / ha ) , ( 2 0 6 . 8 6 : 9 6 . 2 5 : 9 1 . 1 0 N PK k g / ha ) , (131.81:50.25:71.24 NPK kg/ha) and also the maximum cost:benefit ratio of 4.00 (1:400), 5.42 (1:5.42), 3.94 (1:3.94) under irrigated condition during kharif and rabi seasons and under rainfed situation during kharif season respectively.

Thus, among all the treatments, application of Azospirillum + 100% N + PK (Azospirillum + 125:50:125 NPK kg/ha) was found to be most remunerative considering the nutrient uptake, bulb yield and total dry matter production and cost:benefit ratio, which gave the highest returns. This level can be followed for Bellary Red onion irrespective of seasons both under irrigated and rainfed conditions in the Central Dry Zone of Karnataka.

ABSTRACT

Brinjal is an important solanaceous vegetable, which holds coveted position among the different vegetables. Developing hybrids with high yield and resistance to borer would be highly beneficial. The biochemical parameters are used to study the mechanism of resistance to pests and diseases. With this aim, the biochemical constituents were estimated in five intervarietal hybrids and their parents with susceptible variety. The study on biochemical basis of resistance to shoot and fruit borer showed that among the parents of intervarietal crosses, EP 65 had the highest level of peroxidase, polyphenol oxidase and total phenol content in both shoot and fruit and it also recorded high content of solasodine next to APAU Bagmathi. Among the hybrids, the cross EP 65 x Pusa Uttam had the highest level of peroxidase and polyphenol oxidase activity in both shoot and fruit and high level of total phenols and solasodine content next to EP 104 x APAU Bagmathi . The susceptible check (CO 2) registered the lowest value for all the biochemical constituents .The study revealed that the genotypes with high or moderate level of these biochemical constituents suffered less for shoot and fruit borer infestation.

The native gel electrophoretic study showed that for peroxidase enzyme, the intervarietal hybrids EP 65 x Pusa Uttam, EP 12 x MDU 1 and EP 104 x APAU Bagmathi and the susceptible variety CO 2 did not show difference in the induction of isoform (PO-1) and all were single and thick. For polyphenol oxidase (PPO), the intervarietal hybrids and the variety CO 2 showed single and strong band induction

The evaluation of genotypes based on biochemical constituents and isozyme studies revealed the superiority of the parents EP 65, APAU Bagmathi and MDU 1and the hybrids EP 65 x Pusa Uttam, EP 12 x MDU 1 and EP 104 x APAU Bagmathi. The identified hybrids with high yield and resistance to shoot and fruit borer could be exploited for commercial cultivation.

ABSTRACT

Black pepper (Piper nigrum L.), known as the ‘King of Spices’ is an important export- oriented spice crop, valued for its medicinal and condimental properties. A perfect protocol for the rapid in vitro multiplication of this plant is available. However, systemic bacterial contamination is the single major constraint in the large scale in vitro production of plantlets. Based on morphological and biochemical characters, this bacterium was identified as Beijerinckia indica It grows profusely on nitrogen-free Jensen’s agar and solubilizes CaCO in the medium by acid production. It is resistant to a range of antibiotics and produces indole acetic acid. The bacterium is slow growing and has pH optima of 5.5 and temperature optima of 27oC. It has both endophytic as well as epiphytic association with the plant, the colonization being more in the stem and petiole. A single plasmid of 4.0 kb size was isolated from the bacterium and characterized. Competent cells of E. coli DH5a, transformed with this plasmid survived on Jensen’s nitrogen free agar, indicating its ability to fix atmospheric nitrogen. We stipulate that the nif genes are located on the plasmid of the bacterium. Since endophytic bacteria are known to stimulate plant growth through antagonistic activity against pathogens, production of growth promoting substances and inducing systemic resistance in several other agricultural crop species, the symbiotic association between Bejerinckia indica and black pepper could be further exploited through integrated nutrient management for improved growth and yield of this spice crop.

ABSTRACT

Atotal of 45 Gram positive, spore forming and rod shaped bacteria identified as Bacillus species were isolated from the rhizosphere of Chickpea plants. They were studied for their interaction with root borne fungal pathogens was studied using spot test method. Isolates CBS 29, CBS 113, CBS 123, CBS 132, CBS 153 and CBS 155 inhibited the growth of four or more fungi with inhibition zones varied from 1-5 mm. Two isolates CBS 153 and CBS 155 produced siderophores on CAS supplemented agar medium. Further inoculation of these Bacilli on seeds of Chickpea cultivar C235 and H8618 showed inhibitory, stunting or stimulatory effects on plumule and radicle growth depending upon cultivar, bacterium used and stage of seedling growth. Studies on co-inoculation of these isolates with Mesorhizobium and their plant growth promoting activity are being carried out. These co-inoculation studies are important areas of exploitation to improve crop productivity.

WHY, WHEN AND HOW FISH GET PARASITES

Parasites pose a real risk to fishes

All fish are potential hosts to many different species of parasites. Small numbers of parasites are common and probably do little harm. However, all parasites have tremendous reproductive potential and can, under ideal conditions, quickly overwhelm fish in the confines of a tank or pond.

Types of parasites

We can broadly class parasites into two groups. Ectoparasites are found on the external surfaces such as skin, fins and gills, while endoparasites are found in the internal tissues and organs.

Endoparasites are uncommon in ornamental fish. However, there is a wide diversity of blood parasites, worms that colonize the intestines and other parasites that can invade various organs and tissues. Many require an intermediate host, such as snails, birds or the introduction of an infected fish, and so are rare in pond/ aquarium fish. There are a variety of clinical signs which might indicate the presence of endoparasites. Lethargy accompanied by emaciation is a common sign, as are worms protruding from the anus. Identification of sporozoan and protozoan endoparasites often requires microscopic examination of tissues (Chanratchakool et al. 1994).

INTRODUCTION:

An association of two organisms, one living at the expense of other for food and shelter is called parasitism. Parasite factors associated with recognition and selection of the host and the mechanisms in the host responsible for acceptance or rejection of the invading organism were evaluated. Sensory structures in parasites are able to detect differences between different fish species and this ability to discern between fishes may be based on both chemical and mechanical stimuli on the host surface. Complex glycoproteins, proteins, carbohydrates and simple molecules attract parasites or modify their behaviour. (Kurt Buchmann and T. Lindenstrom, 2002)

For most people in their right mind, parasites are disgusting little creatures. The mention of them evokes images of tiny crawlers entering the body of innocent victims by devious means, encrusting themselves within various organs (often with very unpleasant effects), living off their host’s tissues, and then exiting the body, sometimes through scatological avenues, leaving behind hosts that are incapacitated, if not mere shells of their former selves (as is literally the case for some insects). The true facts are not always that gruesome (after all, parasites that have to spend a long time inside a host do not benefit if this host kicks the bucket, because then they die as well) but often enough parasitic reality is not pretty. Ask biology students about their parasitology course, and they will tell you that attending class is like visiting a little shop of horrors. I, for one, came out of my parasitology course with newly developed phobias (mercifully temporary) of such innocuous activities as eating meat and bathing in streams – they represent ways of transmission for some parasites. But students will also tell you that parasites are fascinating because of the complexity of their life cycles and the intricate ways in which they complete these cycles. So fascinating, in fact, that many students eventually become parasitologists and devote their entire lives to studying the little critters. Most of these people work with parasites of livestock or humans, but a few with an equal taste for ethology and ichthyology pursue the more esoteric questions that occupy this page: how fishes avoid getting parasitized, and how fishes alter their behaviour once they get parasitized (Barber et al., 2000)

Occasionally anglers catch fish that show signs of infection or parasitism. Is the fish safe to eat? The usual and safest response to this question is, “When in doubt - don’t.” However, very few fish diseases can be transferred to humans. Almost all fish are safe to eat when thoroughly cooked, smoked or frozen.

Fishes are a valuable resources for hill streams and temperate region people. Not only do they provide important recreation, but they are also a valuable supplement to the family food budget. The anticipation of any fisherman, whether he be a young boy with a cane pole and a can of worms or an “old pro,” is a quality fish for the table. It is the unwritten law of any true sportsman to utilize the fish he catches. The purpose of this publication is to help you, the angler, determine if the fish you’ve caught is worthy of your skillet. Remember, a sick fish will not take the hook (Taraschewski, 2000).

3.1. Determination of Bulk Density of Soil

3.1.1. Determination of Bulk Density of an Undisturbed Soil

Bulk density of soil is expressed as the ratio of the mass (weight) of soil particle to their total volume including the pore space between the soil particles. Alternately, it is the weight of unit volume of dry soil. It is usually expressed in the unit of gram per cubic centimeter (g/cc) or mega gram per cubic meter (Mg/m³). In fine textured soil bulk density varies from 1.00 to 1.60 g/cc, whereas in coarse textured soil from 1.20 to 1.80 g/cc.

In natural condition primary soil particles cohere to each other to form a cluster or an aggregate through the cementing action of various agents like organic matter, oxides of iron and aluminium, carbonates, etc. Aggregate analysis tells one about the structural status, pore geometry which in turn influences the movement of air and water in soil, amount of water stable secondary particles (aggregate) as well as the extent of finer particles aggregated to the coarser particles and the erodibility status of surface soil against wind and water.

Methods of Analysis

Among the several methods of aggregate analysis the commonly used methods practiced in agriculture and related fields are wet sieving and dry sieving method of aggregate analysis.

13.1 Exchange Capacity

Soil colloidal particles carry both negative and positive charges on their surface which attract and hold equivalent amount of oppositely charged ions to their surface. The total number of negative charges present on a given mass of soil or capacity of a given mass of soil to exchange cations or total number of cation held by a given mass of soil is termed as cation exchange capacity (CEC). Similarly, the capacity of a soil to retain anions is known as anion exchange capacity (AEC). The ion exchange capacity of a soil depends upon the type and amount of colloidal particle (clay and organic matter) present in the soil. Ion exchange capacity (CEC / AEC) is expressed as milliequivalent ion (cation / anion, respectively) per 100 g of soil (meq / 100g). It is also expressed as centimoles of charge (positive / negative) per kg of soil [cmol (±) / kg]. Meq / 100g = cmol (±) / kg of soil.

Introduction

Food and nutritional security continues to be the main plank of India’s food policy despite its tremendous achievements on food production front during the last three decades. The Green Revolution helped India to overcome chronic food scarcity and made it self sufficient in food production. The per capita availability of cereals increased from 360 gms/day in 1966 to 422.4 gms/day in 2004. On the other hand, availability of pulses, the main source of protein for over- whelming vegetarian population of India, declined from 48 gms/day to 38 gms/day, which is attributed largely to diversion of land from pulses to cereals crops (Gopalan et al, 2004). The extra income generated due to Green Revolution has increased the access of rural population to a wide variety of foods, like milk, meat, eggs, fish, fruits and vegetables, which perhaps could offset the protein deficiency due to decline in per capita availability of pulses, therefore, resulting in the increase in per capita consumption of protein in rural areas. The trends in cereal consumption indicate that per capita cereal consumption has been declining in most of the states. This trend is more prominent in agriculturally developed states, like Punjab and Haryana. In these states, production and per capita consumption of milk have increased substantially.

The dietary pattern in India remains cereal based and the expenditure shares of foods of animal origin (meat, eggs and fish) and fruits, which are rich in nutrients, are trivial. More than 22 per cent of the population stays below poverty line and generally suffers from various nutritional disorders due to lower purchasing power. The nutrient rich foods like milk, meat eggs, fruits, etc. are highly responsive to income changes. Besides, choice of food and consequently the level of nutrient intake is also influenced by the other economic, social, cultural and climatic factors. Spurt in income growth and increasing consumerism in rural areas in recent years has heightened the need for understanding the food consumption pattern. Using the farm level data from three regions of Maharashtra this paper attempts to examine the pattern of consumption of nutrients by cultivators and sources of supply of different nutrients.

It is the operation of cutting, picking, plucking and digging or a combination of these operations for removing the crop from under the ground or above the ground or removing the useful part or fruits from plants.

Thresher is a machine to separate grains from the harvested crop and provide clean grain without much loss and damage. During threshing, grain loss in terms of broken grain, un-threshed grain, blown grain, spilled grain etc. should be minimum. Bureau of Indian Standards has specified that the total grain loss should not be more than 5 per cent, in which broken grain should be less than 2 per cent. Clean un-bruised grain fetch good price in the market as well as it has long storage life.

It is a machine designed for harvesting, threshing, separating, cleaning and collecting grains while moving through standing crops. Bagging arrangement may be provided with a pick up attachment. The main functions of a combine are: (i) Cutting the standing crops (ii) Feeding the cut crops to threshing unit (iii) Threshing the crops (iv) Cleaning the grains from straw (v) collecting the grains in a container.

With increase in population, demand for basic needs has been steeply rising during the past decades in most of the developing countries of the world. The growing population needs food, clothing, shelter, fuel and fodder for them and their livestock. In India, 50 to 70% of the people are living in rural areas that neither have adequate land holdings nor alternate service opportunities to produce or procure these basic commodities.

The present day living demands quality life. The quality life can be maintained provided our surroundings remain intact or improved to provide means for better living. With increasing advancements in science and technology, we have manipulated our environment without paying adequate attention to consequences. The result has become so alarming that now all the countries of the world are trying to actualize the meaning and concept of sustainability. It is more so in case of agriculture as it forms core base of life supporting system.

The magnitude of manipulation varies from country to country depending upon level of development. It goes without saying that development and manipulation of environment are interrelated having positive and negative effects. To eradicate ill effects of manipulation, we need to understand the meaning of actualizing of sustainability.

The arid region in India is spread over in 38.7 million hectare land. Out of the total 31.7 m hectare lies in hot arid region and remaining 7 m hectare comes under cold arid region. The hot arid region occupies major part of northwestern India (28.7 m ha) and a small pocket (3.13 mha) in southern India. The north western arid region occurs between 22°30’ and 32°05’ N latitude and 68°05’ to 75°45’ E, covering western part of Rajasthan, north western Gujarat and south western parts of Haryana and Punjab. About 62% area of arid region falls in western Rajasthan and 20% in Gujarat. Haryana and Punjab together constitute 7% area of arid region. The state wise distribution of arid region is shown in Table 3.1. Further our discussion is based on the majority area of arid region, belonging to Rajasthan, Gujarat, Punjab and Haryana.

Soil sampling is an integral and essential component of soil fertility evaluation and nutrient management research. The effectiveness of soil sampling is a prerequisite for soil testing to achieve its goals for efficient nutrient management and plant nutrition for improved yield and quality. The underlying basis for soil sampling is that a soil sample taken represents the “population” which may be a plot, field or a watershed. It further implies that nutrient status of the representative soil sample(s) determined in a laboratory would reflect nutrient status of a plot, field or watershed and is of interest for correcting nutrient disorders in the field or watershed.

The most important factor that influences the effectiveness of soil sampling is soil heterogeneity. However, in a relatively homogenous group of fields or plots, a small number of samples may be sufficient to represent the population to a more heterogenous group of fields that would require more number of samples to represent the soil population. Whenever, soil samples to be taken in field following points needs to be kept in mind.

Land resources units or major land resources units are the suitable segmentations of land, based on available natural resources, their potential use and management. Irrespective of terms used by different organizations or institutes, these units have spatial dimension and represent a composite unit for interstate, regional, and national level planning. A typical meaning of these land units can be related to terms like land system. Christian and Stewart (1953) of the Commonwealth Scientific and Industrial Research Organization (CSIRO), Australia devised the ‘Land system’ as the composite mapping-unit which has been defined as “an area or group of areas, throughout which there is a recurring pattern of topography, soils and vegetation”. This system is based on the premise that the land system is expressed on aerial photographs by a distinctive pattern and, as such, the land system can be directly mapped from aerial photographs (Christian and Stewart 1953, Mabbutt and McAlpine 1965). It is a fact that during those period, aerial photographs were more frequently used and studies related to land systems used technique of aerial photogrammetry. As per USDA (United States Developmental Agency), the typical segmentations are; (1) Land Resource Region (LRR), which is the highest level in the hierarchy (2) Major Land Resource Area (MLRA), the second highest level and generally representing broad landforms or a geologic region at a small scale and (3) the Land Resource Unit (LRU).

Introduction

Soil organic carbon (SOC) content plays a key role in maintaining soil fertility in agricultural farm. At present, there has been great interest to reduce the atmospheric CO₂ level through a chain of increasing vegetation carbon pools first and then to store them as soil carbon pool. To quickly assess the soil carbon restoration programmes, it is important to know how much soil carbon is stored in an agricultural farm through adoption of different land management practices. Average SOC content is considered in most soil carbon pool calculations in spite of its large spatial variation in landscape, and thus leads to inaccurate estimate of SOC stock for an area. Therefore, reliable estimates of SOC pools and their spatial variability are essential to establish the soil carbon sequestration programmes at different landscape scales. Here, a case example of assessing the spatial variation at a typical agricultural farm is discussed. The experimental field was located at Badoda village of Jaisalmer district, Rajasthan covering an area of about 76.12 ha. The farm lies between 265^o2′30″-26°53′30″ N and 71°12′15″-71°13′15″ E (Fig. 24.1) and 20 km away from Jaisalmer city in eastward direction. Elevation of the farm ranged from 232 m to 248 m above mean sea level with an overall slope from south to north. Among total area of the farm, 85.38% area was under cultivation in four main blocks: block A, B, C, and D whereas rest area was under grassland.

In India, risk-prone, high altitude area constitutes the easternmost trans-Himalayan part of Ladakh and Zanskar range (Jammu and Kashmir) and some parts of Lahoul Spiti (Himachal Pradesh). Truly described as cold desert with low population density, Ladakh constitutes the easternmost trans-Himalayan part of Jammu and Kashmir in India, comprising two districts, Leh and Kargil, bordering Pakistan and China (Fig. 1).

R aising of healthy vegetable seedlings is most important aspect in vegetable production, because, up to a large extent it determines the productivity and profitability. Nursery raising under open field conditions suffers by a number of biotic and abiotic factors like, continuous rains, too low and too high temperatures, disease and insect-pest etc. For the early establishment in the field and to reduce the cost of production, vegetable seedlings are being raised in plug trays under controlled conditions round the year. Under this system, each transplant grows in an individual cell to reduce the competition among transplants and maintain the uniformity. Plug transplants establish better in field because roots are not damaged in pulling, transplants often result in better stands, and their growth can be controlled more easily through fertility and water management. With the passage of time, a lot of advances have been made in this direction and a number machines have been developed like media sterilizer, media mixer, plug trays filling, seed sowing machine, growth chamber etc. by which the raising of seedlings under controlled environment becomes easier and labour intensive.

The growth is insulated to allow for heating or cooling according to specific germination needs of the seed. This technique reduces fluctuations in temperature and moisture that can occur in an open house. The growth chambers are usually an insulated room in which temperature and relative humidity can be maintained at a precise level. Air circulation is important to ensure uniform temperature and humidity throughout the chamber. Grafting in vegetables is a recent practice to control soil-borne diseases and nematodes, for both field and greenhouse grown crops. In addition, grafted vegetables can produce higher yields and have improved tolerance to environmental stresses, soil salinity and low soil temperatures which is only possible under protected conditions. Thus under present scenario, raising of seedlings under controlled environment offers opportunity to go for commercial nursery with different machines.

Global demand for cut flowers is increasing steadily at around 10 per cent per annum. The share of India in this flourishing trade estimate at over US$ 40 billion per annum is negligible at 0.4 per cent. Floriculture include cut flowers, pot plants, cut foliage, seeds, bulbs, tubers, rooted cuttings and dried flowers or leaves. At international cut flower trade, flowers such as rose, carnation, Chrysanthemum, gerberas, gladiolus, gypsophilla, liatris, nerine, orchids, anthurium, tulips and lilies are preferred. Roses, gerberas and carnation are grown in greenhouses. The open field crops are Chrysanthemum, roses, gaillardia, lily, marigold, aster, tuberose etc. In India, floriculture is emerging as an important economic activity, earning foreign exchange. It has become a potential farm income enterprise. The domestic markets for high-quality flowers have been growing at 10- 20 per cent per year for the last few years. India’s flower business is estimated to be worth $ 400 million at retail, and about $ 100 million in international trade. Flower exports are about $ 30 million, constituting mainly of roses and dried flowers. Both Central and State Governments have been more than proactive and have made large investments in this industry in assisting production and marketing.

A large variety of floricultural crops can be produced in protected environment as economic cash crops for the benefit of farmers. Problems associated with floriculture in hills are small, scattered land holdings and sparsely located population. There is a lack of irrigation facilities due to scarce availability of water resources; widespread natural vagaries like drought, hail storms, frost etc. There is a serious gaps in application of advanced floricultural technologies for improving quality and productivity; high pressure on land use for different purposes like cereal crop production, fodder production, etc. due to low per capita land availability; difficulty in technology dissemination due to difficult terrain, hostile climate, poor communication facilities and sparsely located population. Consuming markets within the state are very less which result in dependence upon distant markets of the county. There is a high post-harvest losses due to lack of modern post-harvest management system; very high temperature differentials in production areas and consumer markets; perishable nature of flowers, resulting in high post-harvest losses during transportation; and distant location of production areas from main roads. High cost of marketing, lack of organised system of marketing, lack of bargaining power with individual growers due to small production levels; inadequate availability of market intelligence to farmers resulting in imbalances in distribution of produce in different markets.