eChapters

ABSTRACT

Astudy was conducted to establish the regeneration capacity of pseudobulb segments of a Dendrobium hybrid orchid (D. nobile L. x D. chrysotoxum L.) in vitro on full strength (MS) and half strength (½ MS) Murashige and Skoog medium. Pseudobulb segments having 0.3-0.5 cm length cut from the in vitro maintained hybrid orchid were inoculated on both media supplemented with different concentrations and combinations of NAA, BAP and Kn. On MS medium the pseudobulb segments failed to respond, however, in ½ MS medium the explants responded well. Responding explants were maximum (35%) on the medium ½MS + 0.1 mgl^-1 NAA + 0.5 mgl^-1 BAP. An average of two (2) shoot buds per explant were regenerated on ½ MS + 2.0 mgl^-1Kn and ½ MS + 0.1 mgl^-1 NAA + 1.0 mgl^-1 BAP. The regenerated plantlets grew healthily on subculture after separation from the pseudobulb segments.

ABSTRACT

Asimple and reproducible protocol for the rapid propagation of Clitoria ternatea L., a flowering garden climber cum medicinally valuable plant, was developed through somatic embryogenesis from the leaf explants. Leaf segments excised from 12 days old in vitro raised seedlings on inducing callus by culturing in MS medium containing 0.5 mgl^-12,4-D and 0.1 mgl^-1 BAP and sub-culturing callus to MS medium containing 1.0 mgl^-1 BAP, produced numerous somatic embryos within 30 - 45 days. Embryos germinated and produced plantlets with intact shoot and root when they were cultured in MS medium devoid of any hormones and supplemented with GA₂ 0.1 to 1.0 mgl^-1. Elongation of plantlets could be achieved on hormone free MS medium in about 3 - 4 weeks. Well- grown plants on transfer to pots, containing sterile sand, in a growth chamber and three weeks later to the greenhouse gave about 40 per cent survival.

ABSTRACT

Successful in vitro clonal propagation of mature tree of Lasoda (Cordia myxa Roxb) has been achieved through single node explant. Both types of organogenesis of shoot and root formation were obtained by placing nodal explant on shoot induction medium and subsequently on rooting medium. More than 90% culture were responsive for in-vitro axillary shoot proliferation on MS media supplemented with 30g Sucrose 8.0 g agar and a combination of 2.0 mg BA and 0.1 mg NAA per litre. After culture period of 6-8 week, the nodal explants with micro shoot were rooted on the MS media supplemented with30 g Sucrose + 3g activated charcol and different level of NAA (0, 1, 3 and 6 mg/ litre). The season and position of explant on the mother plant was also shown to influence in vitro performance of the regeneration in terms of establishment of aseptic culture, percentage of responsive explants and intensity of leaching of growth inhibitory phenolic chemicals.

ABSTRACT

Aloe vera is one of the oldest known therapeutic herb belongs to the family Liliaceae commonly known as guar patta. Gel from fleshy leaves of Aloe vera is rich in 200 nutrients which are used in healing the burns, wounds, gastric ulcers, treatment of diabetes and also used in normal functioning of the liver. Aloe vera is a desert plant which needs water in very less quantity. As Aloe vera is second in ranking in drug production in the world. Government of India is also trying to promote Aloe vera as a crop in dry and semi dry regions of India. As it needs very less and cheaper inputs, Aloe farming promises higher economic gains to farmers. But as the plant grows vegetatively the quality planting material is a problem. Tissue culture provides an opportunity in production of quality seedlings. To optimize the regeneration system in Aloe vera, MS based media were tried to induce shoot formation in cultured shoot tip explants. 6-10 cm long offshoots were collected. Shoot tip explants were cut vertically after sterilization in laminar hood and cultured on MS basal media supplemented with various growth regulators. A total of 23 media were tried for shoot regeneration. All the cultures were incubated under fluorescent light. Different concentrations of BAP (2, 5, 10 mg/l) were used and MS medium with 2 mg/l or 5 mg/l BAP exhibited similar response while BAP at 10 mg/l showed poor shoot formation. TDZ when used at 1 mg/l concentration improved percent shoot formation marginally. Multiple shoots were observed on TDZ containing medium and BAP (2.0 mg/l) supplemented medium in 12-15 days. Multiple shoots were obtained in 12 days when 2 mg/l BAP was added along with 0.18 mg/l IAA. The number of multiple shoots ranged from 4 -15 per explant. The regenerated plants developed roots on MS medium supplemented with 0.1mg/l NAA.

ABSTRACT

In vitro clonal propagation of Smilax zeylanica Linn was attempted. Axillary buds from shoot tip and single node explants were induced to proliferate on half strength MS basal medium supplemented with BA (0.5, 1.0 and 2.0 mg l^-1) and IAA (1.0 and 2.0 mg l^-1). Multiple shoots (6.0 - 10.0 per explant) developed from the axillary buds in about four weeks time in all the treatments tried. However, the highest rate of multiple shoot production was in the medium containing BA 1.0 mg l^-1 and IAA 1.0 mg l^-1. Maximum shoot length was also observed in the same medium. Rooting (83.3 per cent) of micro shoots could be induced on MS supplemented with NAA 0.5 mg l^-1. Individual rooted plantlets could be successfully transferred to soil and established in the field with 80 per cent survival.

ABSTRACT

Ipomoea mauritiana (L.) belonging to the Family Convolvulaceae is an important medicinal plant. The roots, leaves and flowers possess medicinal properties. It is used in indigenous medicine as a tonic, aphrodisiac, galactogogue, diuretic, carminative, expectorant and appetizer. It is useful in syphilis, inflammation, leprosy, diseases of blood and in the improvement of voice and complexion. Tender nodal portions from one year old disease free plants grown in pots were used as the source of explants. The explants were inoculated on half strength MS medium containing 3.0 per cent sucrose and 0.6 per cent agar supplemented with 2,4-D 0.5 mg l^-1. All the explants showed callus initiation after three weeks. The contamination free, one week old callus cultures were used for testing the effect of the different treatments. The treatments comprised of different combinations of BA (0, 1.0, 2.0, 4.0 and 8.0 mg l^-1) and NAA (0 and 0.1 mg l^-1) added to half strength MS medium. The highest rate of shoot regeneration was obtained on half strength MS medium supplemented with BA 4.0 mg l^-1. Rooting of the proliferated shoots could be induced on the same basal medium supplemented with IBA 1.0 mg l^-1 and NAA 1.0 mg l^-1. The regenerated plants were hardened in a humidity chamber and successfully transferred to pots, with 90 per cent survival.

ABSTRACT

In vitro propagation of Plumbago rosea was attempted. One year old plants were used as the source of explants. Nodal explants were inoculated on half strength MS medium supplemented with 2,4-D 1.0 mg l^-1. Induction of callus was observed three weeks after inoculation. The calli were sub-cultured on half strength MS medium supplemented with BA (0.5, 2.0, 3.0 and 4.0 mg l^-1) and IAA (0.0 and 1.0 mg l^-1). Eight treatments with six replications were tried. Benzyl adenine 2.0 mg l^-1 promoted the proliferation of shoots (23.2). Rooting of micro shoots was obtained on MS medium supplemented with IBA 1.5 mg l^-1. The plantlets were then transferred to pots containing sand/soil mixture (1:1) and kept in a mist chamber. The survival rate was found to be 90 per cent.

ABSTRACT

Centella asiatica (Linn.) previously Hydrocotyle asiatica belongs to the family Apiaceae.It is commonly called gotu kola and is rich in triterpene glycosides such as asiaticoside and madecassoside. Health claims range from enhanced memory and longevity, to the treatment of leprosy. It is also used in the treatment of various skin diseases, ulceration, chronic rheumatism, malaria, fever, epilepsy and enlargement of glands. Inspite of its wide range of uses,it is still collected from the wild and commercial cultivation is lacking. A good tissue culture protocol therefore would be useful for commercial propagation and thereby saving the plant from extinction. Of the various explants, nodal segment gave the best response. For direct shoot regeneration from nodal segments, BAP 2.0 mgl^-1, and BAP 1.0 mgl^-1 with Kinetin 1.0 mgl^-1 was found optimum. Callusing was observed in nodal segments and leaf bits when 3.0 mgl^-1 NAA along with 0.3 mgl^-1 BAP was used. ½ MS medium supplemented with IBA 0.5 mgl^-1 and NAA 0.2 mgl^-1 induced rhizogenesis of the regenerated shoots. Rooted plantlets survived well in a combination of pot mixture (1 sand: 1 soil: 1 FYM) and Vermiculite in the ratio of 1: 1.

ABSTRACT

Rubia cordifolia is an effective blood purifier in indigenous medicine. Habitat destruction and indescriminate harvesting is posing threat to its survival necessitating concerted efforts for conservation. The present study is an attempt to standardise in vitro multiplication protocol, a basic step for in vitro conservation, in Rubia cordifolia. Nodal explants cultured in MS basal medium supplemented with BA 1mg l ^-1 and IAA 0.2 mgl^-1 induced axillary bud break. The in vitro formed shoots developed roots on MS basal medium supplemented with IBA 1mg l ^-1. The plantlets were ready for plant out in 100 days of culture initiation and established well on planting out.

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

Kattupadavalam (Trichosanthes cucumerina) is regarded as a laxative and blood purifier, considered beneficial in the treatment of skin diseases. Its entire supply being met from wild, unscrupulous exploitation has led to erosion of genetic resources of this crop. Hence it is imperative that in vitro trechniques are employed to conserve this valuable medicinal species and to evolve feasible protocols for large scale multiplication of this crop. Nodal cultures were established from two months old seedlings of Trichosanthes cucumerina and Murashige and Skoog (MS) medium, supplemented with BA @ 0.5 mg l^-1. Subculture of initiated shoots in the same medium at intervals of three weeks registered enhanced release of axillary buds producing 21 shoots from a single culture at the end of fifth subculture cycle. Elongated shoots were rooted in half strength MS medium, following a pulse treatment with IBA @ 1000 mg l^-1. A single stage root hardening process, wherein, rooted plantlets were subsequently transferred to half strength semisolid MS medium supplemented with 2 per cent sucrose, improved success rate. The rooted plantlets planted out in sterilized media and subjected to a hardening process in a phased manner, survived well.

ABSTRACT

Aquilaria agallocha Roxb. (Thymelaeceae), otherwise known as ‘Eagle wood’ is a large evergreen tree restricted to the eastern parts of India and Bhutan. The tree is valuable for its fragrant wood - ‘Agar wood’ which is tremendously used in the perfumery and incense stick industries. Lack of rapid natural regeneration and over exploitation has reduced its population drastically. Micropropagation offers a rapid means for clonal multiplication and conservation of this endangered species and attempts were made to standardize available protocol for in vitro multiplication. Media and conditions were standardized for culture establishment and propagule multiplication. Multiple shoots were induced in vitro from nodal segments of 10 yr old trees having enhanced axillary branching. Culture establishmnet was strongly influenced by the nature of the explant and the season of collecting the explants. Nodal segments collected during the period March- April from current season shoots showed a better response (90 %) in half strength Murashige and Skoog medium supplemented with 1.0 mg l^-1benzyl adenine and 0.1 mg l^-1kinetin. The rudimentary multiple shoots induced, proliferated in the basal media supplemented with benzyl adenine (0.1 mg l^-1), naphthalene acetic acid (0.5 mg l^-1) and coconut water (10%). This media also supported further multiplication in serial subculturing with a multiplication rate of 1:6. There exists no earlier report on in vitro multiplication of this tree species valued in perfumery.

ABSTRACT

Bacopa monnieri (L.) or Herpestis monniera, commonly known as brahmi, purifies the blood, and is useful in scabies, leucoderma, syphilis, diarrhoea and pyresis. As Brahmi is a major ingredient in several ayurvedic preparations, there is growing demand for steady supply of planting materials. Conventional propagation methods are less efficient than in vitro propagation. However, there are only a few reports on the in vitro propagation of this plant. Therefore, an attempt was made to evolve an improved protocol for the in vitro propagation of Bacopa. Shoot tips and nodal buds along with a portion of the stem excised from field grown disease free plants were taken as the explants. After three weeks of establishment on MS basal medium, the sterile cultures were sub-cultured on MS medium supplemented with different concentrations of BA (0.5,1.0 and 1.5mg l^-1). Rooting was induced on in vitro proliferated shoots by culturing on MS basal medium with NAA 1.0 mg l^-1 and IBA 0.5 mg l^-1. Treatments with BA 1.0 mg l^-1 and IAA 1.5 mg l^-1 recorded the maximum number of shoots (40.9 and 35.2, respectively). The height of the shoots was also significantly influenced by the concentrations of IAA (1.5 or 1.0 mg l^-1) in combination with BA (1.0 mg l^-1), recording 5.4 and 5.5 cm. The shoots with an average length of 3.0 to 4.0 cm were kept for rooting. NAA (1.0 mg l^-1) in combination with IBA (0.1, 0.5, 1.0 or 1.5 mg l^-1) produced significantly greater number of roots. The length of the roots was also greater in this treatment. The plantlets were transferred to pots in a greenhouse and later to the field with ninety per cent survival.

ABSTRACT

In vitro multiplication studies on two peach cvs namely Prabhat and Flordasun grown widely under agroclimatic conditions of Haryana were carried out using nodal and shoot tip explants. Amongst various media modification, M medium containing 1.5 mg^-1 BAP was found the best for shoot induction from both the explants. However, shoot tip showed better response in comparison to nodal explants. Shoot multiplication was highest on M⁷medium (MS+ 6 mg l^-1 BAP). Cultivar response did not differ significantly. Rooting was obtained on M medium containing 0.5 mg l^-1 NAA.

ABSTRACT

The present experiment was conducted to standardize the composition of nutrient media for callus regeneration. Shoot tip, internodal segment, leaf and hypocotyls of seedling grown under controlled condition were used as explants for callus induction. The study revealed that explants collected from younger seedlings showed greater proliferation of callus as compared to those collected from older one. The basal MS medium as well as WP medium fortified with different concentrations of auxins and cytokinins were tried. Initial better results of profuse callus growth with green colour and compact texture having regenerative capacity were obtained by using leaf explants. In all the treatments, the callus initiation occurred at the cut ends and then spread over the surface of the explant as a result of injury. The level of auxins presumable rises and quiescent cells were stimulated to divide rapidly producing callus. The leaf segment explant induced the callus after 9.50 days in medium WPM + NAA 2.5 mg/l with maximum callus growth (976.75 mg) with green, friable callus which was difficult to subculture. White and friable callus occurred within 12.00 days in MS + 2, 4 - D 5 mg/l. The green and compact callus having vigorous growth was observed in MS + NAA 2.5 mg/l within 12.75 days when subcultured on different regeneration media proved recalcitrant for shoot regeneration. On the regeneration medium the callus turned brown while some callus proliferates to produce white growth around it and dried later on.

ABSTRACT

In the studies on callus induction and somatic embryogenesis in acid lime (Citrus aurantifolia S.) var Sai-Sharbati, different ex-plants and different combinations of growth regulators (NAA, IBA and BA) in MS basal media were tried, the results indicated that cotyledonary segment was the best explant for callus induction among root tip hypocotyl stem, leaf, epicotyl stem and shoot tip explants tested of. The callus grown from epicotyl and hypocotyl stem explant was greenish white and compact. Whereas callus derived from cotylidonary segment and leaf segment was green and friable . Root tip and shoot tip did not exhibit callusing. The callus derived from epicotyl stem and hypocptyl stem explant responded shoot bud formation in MS medium supplemented with NAA 0.2mg/l + BA 0.5mg/l with or without ME 100mg/l. In somatic embryogenesis, full grown callus derived from epicotyl stem explant induced embryo formation within 28.33 days and more shoot bud (6.33) formation.

ABSTRACT

In vitro culture induced genetic variation constitutes an important source of variability for the improvement in ginger (Zingiber officinale Rosc.). Hence attempts were made to standardize indirect method of in vitro plantlet regeneration in ginger using various explants like sprouted bud, shoot tip, leaf and pseudo stem. Explants from two cultivars of ginger viz. Maran and Rio-de-janeiro were cultured in Murashige and Skoog (MS) medium supplemented with various levels of 2,4-D and in combination with different levels of BA. Cultures were incubated under two different culture conditions viz. light and dark. Callusing was observed in all the explants except mature leaf in MS medium supplemented with 2,4- D alone (1 - 2 mg l^-1) and in combination with BAP (0.5 - 3.0 mg l^-1). Shoot morphogenesis was achieved from one month old calli in MS medium supplemented with BAP (3.0 mg l^-1). Regenerated shoots were subcultured to medium of same composition for further shoot proliferation and rooting. Plantlets produced were hardened and planted out. From the present investigation, highly efficient protocol for indirect organogenesis in ginger could be developed and the response of two cultivars at various stages of morphogenesis could be studied in detail.

ABSTRACT

Aprotocol has been developed for the induction, maturation and germination of somatic embryos from leaf explants of Hevea brasiliensis (clone RRII 105). Leaf explants were cultured with their adaxial sides on modified Murashige and Skoog (MS) medium supplemented with different combinations of phytohormones such as 2,4-D & BA, NAA & BA as well as 2,4-D, BA and NAA. Compact calli could be developed from the cut ends of the explants on media containing 2,4-D (1.5 mg/l) and BA (1.0 mg/l) whereas pale yellow friable calli was obtained on media which contained NAA (0.2 mg/l) along with 2,4-D (1.2 mg/l) and BA (1.0 mg/l). The calli formed were detached from the explants and sub cultured for proliferation in medium containing reduced auxin (0.4 mg/l 2,4-D) and slightly increased level of sucrose (40 g/l). Proliferated calli were then sub cultured for embryo induction in modified MS medium supplemented with different auxins and cytokinins. Embryo induction could be achieved in modified MS medium containing BA (2.0 mg/l), GA (1.0 mg/l) and NAA (0.2 mg/l) and maturation occurred in WPM medium containing BA (0.3 mg/l), TDZ (0.5 mg/l) and GA (1.5mg/l). The cotyledonary stage embryos developed into plantlets on transfer to hormone free ½ MS medium. A distinct feature of this study is the induction of somatic embryogenesis from leaf explants of Hevea which has not been reported previously. This explant could be used further as an ideal target tissue for Agrobacterium mediated genetic transformation in Hevea.

ABSTRACT

Immature zygotic embryos were isolated from field grown papaya fruits harvested at 90-105 d post-anthesis. The embryos were placed on half-strength Murashige Skoog (MS) medium supplemented with 2, 4-D (2.0 mg l^-1) and cultured under dark for a period of 2 months. The frequency of callus formation was around 66%. After 2 months, calli were transferred onto a half-strength MS basal medium and cultured for 3 months with frequent subculturing (once in 3 wk) on the same medium. The frequency of somatic embryo formation was around 36.6%. The somatic embryos on MS medium supplemented with BAP (0.4 mg l^-1) and NAA (0.02 mg l^-1) germinated and produced shoots. The emerging shoots of 2-3 cm height with 2-3 trilobed leaves were placed onto an MS basal liquid medium with IBA (1.0 mg l^-1) for root induction. The plants developed with shoots and roots were planted in a pot-mixture (sand:soil:FYM) containing VAM.

ABSTRACT

Shoot organogenesis from several explant types excised from in vitro grown plants of local elite brinjal (Solanum melongena L.) cv. Co2 was studied in response to the supplementation of thidiazuron (TDZ), BAP, IAA and NAA. Cotyledons and leaves were found to be the most responsive explants. High shoot bud induction rate (>50 shoot buds/explant) was achieved in the presence of 0.044 mg/l TDZ. The organogenic calli were subcultured in the same shoot bud induction medium for shoot development. Among different growth hormones, TDZ @0.044 mg/l induced more number of shoots per explant compared to BAP, IAA and NAA combinations. Efficient rooting was observed on half strength MS medium supplemented with 0.5 mg/l IAA. Higher percentage of rooting was achieved only when the well developed shoots were directly transferred to soil.

ABSTRACT

Papaya (Carica papaya L.) is an important crop in the tropics and subtropics for export of fruits and above all, for local consumption. Cultivation of papaya faces with problems due to its heterozygosity, dioecious nature and susceptibility to a large number of viral diseases. Crossing between two hermaphrodites will produce the highest ratio of fruit bearing female trees, which is of homozygous dominant andromonoecious types which are always letha l due to po st fertilization barriers leading to their abortion. The gynodioecious varieties of papaya have the M1M1 forms while selfing and hence for explant selection , gynodioecious varieties like Sunrise solo and CO7 were prefered Embryo culture is one of the earliest forms of in vitro culture applied to solve practical problems and is probably the tissue culture techniques that has proven of greatest value to breeders. Ovule culture is practised in a case when small (or) young embryos that abort at early stages of development and are difficult to isolate. This necessiates the development of a protocol for initiation, multiplication and regeneration of ovular callus of papaya.

ABSTRACT

The present experiment was conducted in order to develop a protocol for rapid in vitro propagation of pomegranate Cv. Mridula. Shoot tip and nodal segment explants selected from mature plant were cultured in MS medium supplemented with NAA and BAP in different concentration and combinations. To control phenolic browning, sub- culturing of cultures was under taken at an interval of first and third day after inoculation. The MS medium supplemented with NAA 0.4 mg/l + BAP 1.0 mg/l showed highest percentage of shoot differentiation with 77.77 per cent and 81.25 per cent response from shoot tip and nodal segment explant respectively. In the same media, earlier shoot initiation as well as more number of multiple shoots/culture were obtained. The shoots when elongated up to 2.5 - 3.0 cm length were transferred for rooting in the ½ strength MS media supplemented with auxins. There was no significant difference for root induction among the type of auxin used either NAA, IBA or both in combination. The concentration of auxins 0.5 mg/l was found to be optimum. Rooted plantlets after hardening in green house gave 49 per cent survival.

ABSTRACT

Direct shoot organogenesis from several explant types excised from in vitro grown plants of local elite tomato cv. PKM1 was studied in response to zeatin, BAP, IAA and NAA. Cotyledonary leaves were found to be the most responsive explants. High shoot bud induction rate (>25 shoot buds/cotyledonary explant) was obtained in the presence of 2 mg/l zeatin. The organogenic calli were subcultured onto the same shoot bud induction medium for shoot development. Among different growth regulators tested, zeatin @ 2 mg/ l induced more number of shoots per explant compared to BAP, IAA and NAA combinations. Rooting was efficiently induced on half strength MS basal medium supplemented with 0.5 mg/l IAA. The effects of various growth hormones on tomato regeneration on rooting were discussed.

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

Dissected shoot tips from healthy suckers of banana var. Meitei Hei (local variety) were inoculated on Murashige and Skoog (MS) medium supplemented with different concentrations and combinations of plant growth regulators viz., NAA and BAP. After 15 days of incubation 50% of the shoot tips turned green in the medium with 5.0 mgl^-1 BAP. A maximum of 85.7% of the explants produced phenolic exudates in MS + 5.0 mgl^-1 BAP. After one month the explants were subcultured in fresh medium with the respective concentrations and combinations of plant growth regulators. After 75 days of incubation an average of 2.20 microshoots were induced in 78.57% of the explants in MS + 5.0 mgl^-1 BAP. The regeneration of shoots, leaves and roots was more proportionate in MS + 0.1 mgl^-l NAA + 0.5 mgl^-1 BAP. Under the treatment the microshoots had an average height of 1.19 cm with 4.13 leaves and 2.40 roots. The multiple microshoots were separated and subcultured on MS + 0.1 mgl^-l NAA + 0.5 mgl^-1 BAP for proper development. After 120 days the completely regenerated plantlets were hardened under green house environment.

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

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

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

Jasmine is one of the economically most important flower crops cultivated for its fragrant flowers and valuable essential oil. In vitro studies to explore the possibility of regeneration of plantlets from different explants and to undertake biochemical analysis to detect the flavour compounds if present in the in vitro cultures were taken up with local varieties of Jasminum grandiflorum.

Among the different explants tried, leaf bits were found ideal for callus induction, followed by petals and shoot tips. MS medium with 2, 4-D at 1.25 ppm was the suitable medium for callus induction in leaf explants. Miller medium with NAA at 1.25 ppm and BAP at 1.25 ppm was the suitable medium for callus induction in petal explants collected from 18 days old buds of local varieties of Jasminum grandiflorum. Among the different media combinations tried, MS medium supplemented with 0.2 ppm NAA and 0.3 ppm GA₂ is the best medium for callus induction in shoot apex explants of 10mm size. Direct regeneration of plants was obtained in 10 per cent of shoot apex explants cultured in MS medium supplemented with 0.2 ppm GA₁ and 3 ppm BAP in 60 days. A maximum of 95 per cent embryogenicity is induced in leaf callus transferred to MS basal medium supplemented with 1.5 per cent sucrose from MS medium with 2, 4-D at 1.0 ppm.

The peroxidase assay indicated that embryogenic calli had six isoperoxidases while the non-embryogenic had only two. Biochemical analysis of the callus samples showed high Phenylalanine ammonia lyase and phenol indicating the initiation of phenolic pathway, which branches out and ultimately leads to the synthesis of flavour compounds in callus.

ABSTRACT

Donor-recipient protoplast fusion vis-à-vis cybridization is an effective technique to transfer plasmon-coded traits in cultivated tetraploid (2n=4x=48) potato (Solanum tuberosum L.) from its diploid (2n=2x=24) cross-incompatible wild relatives. However, the method, although attractive, is difficult in terms of not only inactivation of nuclear and plasmonic genomes of the participating donor and recipient protoplasts, but also post- fusion culture and regeneration of putative cybrids. Here, we report an improved method for donor-recipient protoplast fusion and subsequent post-fusion culture and regeneration of electrofused protoplasts in potato. In the present experiment, Solanum verrucosum Schlechtd. (2n=2x=24) accessions CPC 1339 (CGN No. 17774) and HAW 2246 (CGN No. 17766) containing sensitive [Tr^s] plasmon for tetrad-type cytoplasmic male sterility were used as donors and S. tuberosum subsp. tuberosum cvs Kufri Ashoka, Kufri Chipsona-1 and Professor Broekema as recipients. For nuclear inactivation, the in vitro-cultured donor plants were exposed to 1000 Gy of unfiltered γ-rays before protoplast preparation using a revised protoplast isolation medium (PIM) containing 2.0 % Cellulase ‘Onozuka’ RS and 0.25 % Macerozyme R-10. The recipient protoplasts were treated with antimetabolite iodoacetate (1.0 mM ) for 45 min at 10 °C for chondriome inactivation. The protoplasts were aligned in an amplitude of 300 Vcm^-1 for 0.5-1.0 s before being electrofused by one DC pulse of 600-800 Vcm^-1 for 40 μs using a Cell Electrofusion Processor FPH 01001 (Bioelectronics Corporation, Troy, Michigan). The fused protoplasts were immobilized in alginate-plates, and cultured on modified VKM medium containing 0.3 M glucose at about 400 mOsmol (pH 5.6). After 8-10 weeks, the developing protocalluses were dissociated from alginate-plates and cultured for regeneration on MS medium supplemented with varying concentrations of zeatin/ zeatin riboside and gibberellic acid. The protocalluses derived from electrofusion between donor S. verrucosum accession CPC 1339 and recipient S. tuberosum cv. Kufri Chipsona-1 could be successfully regenerated into plantlets. Morphological as well as molecular-genetic characterization of regenerated microplants, both for nuclear and chondriome genomes, confirmed the putative cybridity as well as established the extent and pattern of mitochondrial recombination following donor-recipient protoplast fusion. The results have been discussed in relation to donor-recipient protoplast fusion approach and its potential application in potato genetic improvement.

ABSTRACT

The investigation was carried out to develop protocol for micropropagation of acid lime (Citrus aurantifolia S) var. Sai-Sharbati. Shoot tip and nodal segment explants were obtained from axenically grown seedlings having 21 to 30 days age. Direct regeneration of shoots, roots and whole plant without intervention of callus was obtained from both the explants on MS basal media. In both the explants 100 per cent shoot proliferation was induced in nutrient medium MS + BA 0.25 mg/l + ME 200 mg/l. The shoot proliferation rate was more (5.0) in nodal segment as compare to the shoot tip explant (4.33). Regenerated shoots of more than 2.5 cm length with minimum of 4 leaves were transferred for rooting. Half strength MS medium supplemented with IBA 1.0 mg/l was best for root induction and root initiation within 15.66 days. More than 75 per cent plantlets were survived after hardening period of four weeks.

ABSTRACT

Immature seeds of Garcinia indica were excised from the green fruits and cultured on Woody Plant Medium (WPM) with a combination of auxins and cytokinins. Somatic embryos were obtained on the media supplemented with BAP (0.5-5.0 mg/l) alone or in combination with NAA 90.5 mg/l) with 80 per cent frequency within a period of 2-3 weeks. Subculture of primary embryos on maturation medium containing BAP (3.0 mg/l) supplemented with IAA (0.5-1.0 mg/l) and / or Kinetin (1.0 mg/l) gave rise to clusters of secondary somatic embryos. In the subsequent subculture on hormone free half strength WPM the embryo clusters germinated with repetitive secondary embryogenesis. About 70 per cent somatic embryos germinated into complete plantlets, which were successfully transferred to the green house conditions.

ABSTRACT

The totipotency of triploid endosperm tissue is exploited in many vegetatively propagated crops. Hevea brasiliensis, the most important commercial source of natural rubber, is a highly heterozygous perennial tree with a long breeding cycle. Conventional method of triploid production by crossing a diploid with an artificially induced tetraploid is a lengthy and laborious process. Hence in vitro regeneration of plants from endosperm tissue provides an easy and direct approach for the production of large number of triploids. Hevea fruits at different developmental stages were collected and sterilized using 0.1% HgCl₂ for 15 minutes. Seeds were dissected out and the embryos and inner integuments were removed. Endosperm is cut into small pieces and cultured over MS medium supplemented with various levels of sucrose, phytagel and growth regulators viz BA, Kin thidiazuron, 2,4-D, IBA, NAA, zeatin & GA. Organic supplements viz. yeast extract, casein hydrolysate, coconut milk and banana powder were used for callus and embryo induction. Optimum callus induction was obtained in media supplemented with 2,4-D (2.0 mg ^-1) and Kinetin (3.0 mg^-1). On further subculture of the primary calli to medium containing zeatin (1.0 mg ^-1), embryogenic calli could be obtained. Embryos were induced in MS medium supplemented with ABA (0.3 mg ^-1) , Kin (0.3 mg ^-1) and GA (0.5 mg ^-1). Maturation, germination and bipolar differentiation of the embryos were achieved in MS medium devoid of growth regulators. Root tips from the germinating embryos were subjected to cytological analysis and found to be triploids (3n=54). Regeneration from Hevea endosperm is being reported for the first time. The results indicates that like many other crops, Hevea endosperm responds well under in vitro conditions and endosperm culture could be utilized as a viable technique for triploid plant production.

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

Techniques could be standardized for the induction, initiation, maturation and germination of somatic embryoids from the nucellar tissue isolated from 30-45 day old fruits of mono embryonic mango variety Neelum and poly embryonic variety Vellari Manga. The treatment half strength Murashige and Skoog basal medium containing 2,4-D 5.0 mgl^-1, GA3 5.0 mgl^-1, glutamine 400 mgl^-1, coconut water 200 mll^-1, activated charcoal 500 mgl^-1, sucrose 60 gl^-1and agar gl^-1was found to be the best in induction of embryogenic callus. The treatment 2,4-D 4.0 mgl^-1 + BA 1.0 mgl^-1+ GA3 5.0 mgl^-1in half strength MS basal medium supplemented with glutamine 400 mgl^-1, casein hydrolysate 500 mgl^-1, sucrose 60.0 gl^-1, coconut water 200 mll^-1and agar 6.0 gl^-1was the best in initiating somatic embryos from the induced nucellus of the three varieties. In the variety Neelum BA (8.0 and 16.0 mgl^-1) and kinetin (8.0 to 32.0 mgl^-1) were as effective as 2,4-D in inducing somatic embryogenesis. Polyembryonic variety Vellari Manga showed better response to induction treatments than the mono embryonic varieties. B5 major salts with MS minor salts in combination with 40 gl^-1sucrose, 10 gl^-1PVP, 200 mll^-1coconut water, 5.0 mgl^-1 ABA, 100 mgl^-1 casein hydrolysate and 6.0 gl^-1agar were the best suited for the maturation of the somatic embryos. The positive influence of cobalt chloride, casein hydrolysate and coconut water on the germination of embryoids of both mono and poly embryonic mango varieties could be well established. A basal medium consisting of B5 major salts and MS minor salts supported the highest percentage of germination of somatic embryoids in Neelum and Vellari Manga. However, abnormalities in germination were observed in most of the cases. Excellent germination of somatic embryos was observed in a liquid medium consisting of half strength B5 macro salts and full strength MS micro salts and supplemented with GA3 1.0 mgl^-1+ glutamine 400 mgl^-1 + sucrose 30gl^-1.

Waste is not actually waste but is the by-product of various activities of human life. The unclean handling of these wastes creates problem for public health departments and local bodies. The classification of waste depends on the agencies that classify these wastes according to the area of interest and method of disposal viz. medical field, agricultural field, local bodies, industries etc.

In the present paper, the emphasis is given to the classification based on agricultural activities which includes a) Agricultural marketing waste b) Meat and fish marketing waste.

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

The Plant Growth Promoting Rhizobacteria (PGPR) is a group of rhizosphere-colonizing bacteria producing substances which increase the growth of plants and/or protect plants against pathogens. The use of PGPR has become rather common practice and is on the rise in many regions of the world. Inoculation with PGPR also aims at reducing the application of potent ially pollut ing chemical fertilisers and pesticides. Biocont rol microorganisms have unquestionable potential for managing plant diseases, insect pests and nematodes besides increasing crop productivity. Interest in biological control has recently been intensified because of imminent bans on effective pesticides, widespread development of pesticide resistance in insect pests and plant pathogens and a general need for more sustainable pest control strategies. Active and long-term colonization of the root surface of the plant and effective expression of disease-suppressive traits are generally considered prerequisites for successful suppression of horticultural crop diseases by rhizobacteria. The important mechanism of biocontrol by PGPR involve competition and production of antibiotics such as 2,4-diacetylphloroglucinol (DAPG), pyoluteorin (PLT), pyrrolnitrin, phenazine-1-carboxylic acid (PCA), 2^-hydroxy phenazines and phenazine-1-carboxamide (PCN). Siderophores, including pyochelin and pyoverdine which chelate iron and other metals also contribute to disease suppression by conferring a competitive advantage to biocontrol agents for the limited supply of essential trace minerals in natural habitats. Induced systemic resistance (ISR) is a state of increased defensive capacity developed by the plant when appropriately stimulated, through activation of latent resistance mechanisms induced by diverse agents including rhizobacteria. Microplants are first grown in vitro under aseptic conditions devoid of microorganisms. They are then transferred to a post vitrum substrate for acclimatization. By creating a beneficial rhizosphere in microplants at an early stage, the plants could be better protected against biotic and abiotic stress that occurs in the greenhouse or in the field. The beneficial rhizosphere can be created by biotization of microplants with PGPR. The search for PGPR to control postharvest decay of fruit crops has been actively pursued and promising strategies have been practiced nowadays. Biological control of postharvest diseases of perishable horticultural crops with PGPR is complex and involves a number of mechanisms to suppress the development of the disease. PGPR, being a potential candidate in disease management through multiple mode of action, it becomes highly imperative to know its different role in the management of plant pathogens.

Introduction

The common mycorrhizal association in most of the plants is the arbuscular type occurring in the majority of agricultural and horticultural crops. Arbuscular mycorrhizae (AM) are formed by non-septate Zygomycetous fungi belonging to the genera Glomus, Gigaspora, Acaulospora, Sclerocystis, Entrophospora, Scutellospora, Archaeospora and Paraglomus in the order Glomales. These fungi are obligate symbionts and have not been cultured on nutrient media. These endophytes are not host specific although evidence is growing that certain endophytes may form preferential association with certain host plants. Several investigations indicted that even in unsterile soils plants do respond to inoculation with efficient strains of arbuscular mycorrhizae. Numerous experiments have been conducted in different parts of the world confirming this growth improvement. The increased growth of mycorrhizal plants is favoured in soils with low to moderate fertility. More specifically, soils favouring mycorrhizal growth stimulation usually have one or more essential nutrients, especially phosphorus, in limiting concentrations.

The mechanism of improved plant growth caused by mycorrhizal inoculation has been investigated by many workers. Greater soil exploration by mycorrhizal roots as means of increasing phosphate uptake is well established. They also improved the uptake other diffusion-limited elements like Zn, Cu, etc. The other beneficial effects are their role in the biological control of root pathogens, biological nitrogen fixation, hormone production and greater ability to withstand water stress (Bagyaraj, 1984).

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

Of the total production of the crop yield, only 63 per cent is available for human consumption. The remaining is lost in more or less equal proportions to weeds, pests and diseases. Prior to genetic engineering, the exchange of DNA material was possible only between individual organisms of the same species. In the field of agriculture for instance, farmers have continuously modified naturally occurring species through seed selection and controlled breeding. With the advent of the recombinant DNA technology, it has however been possible to identify specific genes associated with desirable traits in one organism and transfer those genes within and beyond the boundaries of species into other organisms.

1. Genes for herbicide resistance

Modern agriculture has developed a range of effective herbicides to tackle the effects of weeds on crop yield. Some of the most useful of these are broad-spectrum herbicides because they are active against a wide range of weeds. However, these can only be used at times when the crop is not itself vulnerable to herbicide action. The development of herbicide-resistant crops therefore offers the opportunity to spray crops at the most effective time to kill weed species without damaging the crop plants. By definition, herbicides are much more toxic to plants than to animals. Therefore, it is not surprising that they generally affect ‘plant-specific’ biological processes. The herbicidal activity of many herbicides has been found to result from the specific inhibition of a single enzyme/protein. The following are four distinct strategies for engineering herbicide resistance: i. Overexpression of the target protein, ii. Mutation of the target protein, iii. Detoxification of the herbicide, using a single gene from a foreign source and iv. Enhanced plant detoxification.

ABSTRACT

The coastal ecosystem happens to be one of the most productive ecosystems. This ecosystem has been under different kinds of threats such as climate change and consequent rise in sea level, increase in population and depletion of natural resources. All this has given rise to an increase in the level of abiotic stresses such as salinity, alkalinity, and drought affecting the agricultural productivity in the coastal region. Salinization is posing an increasing problem in coastal and agricultural areas reducing plant productivity and yield. Salinity is one of the major abiotic stresses decreasing the plant productivity.

Salinity is a significant factor limiting agricultural productivity and affecting about 9x 10⁸ hectares worldwide. Poor quality of water for irrigation and current unsustainable irrigation practices has significantly resulted in salinization and other forms of soil damage. About one third of all irrigated land is affected by salt due to secondary salinization. It is estimated that 50% of all arable land will be salinized by the year 2050. The problem of secondary salinization is also becoming more serious as it represents loss of highly productive lands. Added to this is the problem of coastal salinity where intrusion of seawater into arable land due to erosion of coastal habitat has rendered it unsuitable for cultivation. Salt-affected soils (~11 million ha in South and Southeast Asia) are found along coastlines or in inland areas where evaporation is greater than precipitation.

ABSTRACT

The process of developing new crop varieties involves many steps and takes several years. In recent times, biotechnological advances have helped in reducing these considerably. Apart from the techniques of haploid culture and genetic engineering, one of the tools which is making it easier for scientists to select plant traits and develop new varieties is the use of molecular markers. Molecular markers can be used for (a) characterization of germplasm (b) varietal identification and clonal fidelity testing (c) assessment of genetic diversity (d) validation of genetic relationships and (e) marker- assisted selection. These have widespread applications in management of genetic resources as well as in breeding programmes. Marker-assisted selection has practically revolutionized breeding programmes. Traditionally, plant breeders have selected plants based on their visible or measurable traits called the phenotype. But this process can be difficult especially in the case of multigenic or quantitative traits. Molecular markers can be used to trace linkages with traits of importance. In the area of horticulture, this is a very useful tool in tree breeding, where the breeder has to wait for several years for phenotypic expression of the desired trait. A number of DNA marker technologies are now available and rapid advances are being made in the development of more sensitive marker technologies. The techniques involved, the various applications of DNA marker technologies in horticultural crops and future perspectives in the national context have been discussed.

ABSTRACT

Genetic improvement of crop plants through conventional plant breeding has made tremendous contributions to the breakthrough in the global agricultural production. Recently, an array tools and techniques in the field of molecular biology has become available for supplementing the conventional genetic approaches. Consequently, new integrated approaches are being designed. One of the approaches employs molecular markers for genome mapping, gene tagging and marker assisted selection (MAS). With the complete sequencing of whole plant-genomes and a large number of random cDNAs in many different crop species, newer opportunities are emerging. This presentation is an attempt to briefly describe the current applications of molecular markers and to highlight their future prospects.

Molecular markers

Molecular markers are heritable differences in nucleotide sequences of DNA at corresponding position on homologous chromosomes of two different individuals, which follow a simple Mendelian pattern of inheritance. These differences are detected employing two basic techniques: (a) Southern blot hybridization and (b) Polymerase chain reaction (PCR). Restriction Fragment Length Polymorphism (RFLP) is the first molecular marker system to be conceived and developed. It is based on the southern blot technique. Markers such as random amplified polymorphic DNA (RAPD), sequence tagged site (STS) and amplified fragment length polymorphism (AFLP) are generated by enzymatic amplification of DNA by extension of oligo nucleotide primers and therefore, are based on PCR. Single/simple nucleotide polymorphism (SNP) markers are based on DNA sequence differences as revealed by sequencing and assayed by various techniques.

ABSTRACT

Activity patterns of Grey Jungle fowl, Gallus sonneratii were studied at Gudalur Range (9º 37’ N, 77º 16’ E) which is 23² km area in Theni Forest Division, Western Ghats, Tamilnadu from January to December 2005.

ABSTRACT

In social Hymenoptera, the females carry out nest building, brood care and foraging, while males generally do not take part in any of these social behaviours and act solely as reproductives. The interesting phenomena of cooperation and altruism

Botany :The cabbage plant, Brassica oleracea, is an herbaceous annual or biennial vegetable in the family Cruciferae grown for its edible head. The head of the cabbage is round and forms on a short thick stem. The leaves are thick and alternating with wavy or lobed edges and the roots are are fibrous and shallow. The plant produces large yellow flowers. The densely leaved heads can range in size from 0.5 to 3.6 kg (1-8 lb) depending on variety. The plant is usually grown as an annual.

ABSTRACT

Queens of 4 post-emergence colonies of primitively eusocial wasp, Ropalidia marginata were observed for their propensity to acquire and handle foraged material on naturally occurring free foraging nest. The queens were inclined to acquire pulp loads than food loads.