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Microbial inoculants in agriculture, horticulture and forestry can be defined as preparations containing strains of microorganisms which can augment the microbiological process such as nitrogen fixation, phosphate mobilization, excretion of growth promoting substances, decomposition of organic wastes, biocontrol of insect pests and diseases etc. Thus they become an important component of sustainable agriculture. Microbial inoculants are based on renewable sources available in soil and nature and are low cost input and eco-friendly. These inoculants carrying the microorganisms when applied to soil/plant promote plant growth and productivity.

Maturity can be defined as the attainment of a particular size or stage after which ripening takes place. It is also called physiological maturity. However,horticultural maturity is defined as the stage of development, when a plant or plant part possesses the prerequisites for utilization by consumers for a particular purpose. Mango, tomato, cucumbers, lettuce, peppers, etc. are harvested at various stages depending on the objective of disposal (horticultural maturity) prior to reaching physiological maturity, or completion of growth phase.

Maturity indices are the most important for deciding the stage of harvesting and to reduce post-harvest losses. The post harvest life of fruits are mainly controlled by maturity. Maturity signs are also called maturity standards or maturity indices. Maturity signs help in judging maturity of fruits and vegetables. There are many methods to determine maturity. The most common is the size and shape of fruit, change in colour, softening of tissues (fig, sapota), ease of detachment from the stalk (sapota, annona), shriveling of fruit stalk (watermelon), drying of nearest tendril (watermelon), days from blooming to picking maturity, sound by tapping jack and watermelon, when ripe produce hollow and dull sound on tapping but produce metallic sound if unripe etc.

Maturity of Cashewnut

Cashew fruit has two parts namely cashew nut (actual fruit) and cashew apple (pseudo fruit). Development of these is not parallel. Cashew nut develops first and the pseudo fruit develops later. It takes 60 days for both the nut and the pseudo fruit to develop completely since anthesis. Development of cashew apple and nut has been studied by number of workers in different cashew varieties (Rao et al., 1962; Augustin and Unnithan, 1981; Mohan Kumar et. al., 1984; Antarkar and Joshi, 1987). According to the report, specific gravity could be considered as physical index of maturity of nut in cashew varieties of V-1, 2, 3, 4 and 5 (Antarkar and Joshi, 1987; Mohan Kumar et al., 1984). In Thailand, the nut reached maximum size in 4 weeks after fruit set, hardened in the subsequent week and declined in size by 10 per cent at harvest (Sumrit Feungehan et al., 1989). Augustin and Unnithan (1981) have reported that the growth of nut is faster during early stage of development than that of fruit. All these reports indicate that the cashew nut develops earlier than cashew apple. Changes in the composition of cashew nut and apple during development have been looked into by various workers. Hariharan et al. (1985) have reported decrease in amino acid content in kernel with increased maturity. Cashew kernel lipid, free amino acids and CNSL have been shown to increase with increased maturity. Similarly, cashew kernel phenols have been shown to decrease with maturity. Changes in the kernel sugars and starch were not uniform (Anon., 1998).

Introduction

Measurement of pH of a solution and preparation of different types/strength of buffers are common practices in a laboratory, particularly in the Biochemistry and Molecular Biology laboratories. Therefore, in this chapter you will be acquainted with the procedures of measuring pH of a solution as well as preparation of some of the commonly used buffers in a laboratory.

Potential or Power of Hydrogen Ion (pH)

Measurement of pH of a solution is measuring the molar concentration of hydrogen ion [H+] in the solution, which is an indication of the acidity or basicity of the solution. The symbol pH stands for “power of hydrogen” and numerical value for pH is just the negative logarithm of the molar concentration of hydrogen ions [H+]. The ionic product of water (Kw ) is the basis for the pH scale. The total hydrogen ion concentration from all the sources and it can be experimentally measured.

The pH scale designates the concentration of H+ (and thus of OH−) in an aqueous solution, which ranges between 1.0 M H+ and 1.0 M OH−. The term pH is defined by the expression

Thus, the ionic product of water makes it possible to calculate the concentration of H+, with given concentration of OH−, and vice versa. The value of 7 for pH of a neutral solution is not an arbitrarily chosen figure; it is derived from the absolute value of the ionic product of water. A solution having pH greater than 7 is basic, and the concentration of OH− is greater than that of H+. A solution having a pH less than 7 is acidic.

Biofertilizers improve the plant growth due to changes in the microbial community of rhizosphere by production of several substances. Normally, biofertilizers promote plant growth either by facilitating nutrient absorption or by secretion of plant hormones. Biofertilizers also cause inhibitory effects by acting as biocontrol agents on various pathogens so that the growth of plant is enhanced. The mode of action could be either direct or indirect methods

Before carry out any ethnobotanical work, first define the goal of the assignment or study before selecting the approach, which best suits the interests, budget and schedule. Most of the methods used in ethnobotanical studies are time taking and costly because several field trips are required in several seasons for covering different ritual occasions and seasonal farming activities which are continue for a number of years for completion of an assignment. In this way, an assignment may be very long or short as per selection approach of an ethnobotanist. Long-term assignment or projects may be continue for several years and they require sufficient financial input. When sufficient financial add and time does not available to accomplished long term assignments, in that case a Rapid Ethnobotanical Appraisal (REA) can be done.

The adoption of modern agricultural technologies has culminated into serious problems of pesticide resistance in major pests, resurgence in minor pests, elimination of populations of natural parasites, predators and pollinators, environmental pollution, pesticide residues in food chain and health hazards. World Health Organization (WHO) estimates one million pesticides poisoning cases and 20,000 deaths every year globally. This is due to high pesticide residues in food chain including cereals, pulses, vegetables, fruits, milk and milk products (including mother’s milk), fishes, poultry, meat products and water. Twenty five per cent of Indian food products contain pesticide residues above tolerance level compared to only 1.2% globally.

Herbicides are the chemical substances used to kill weeds, i.e., unwanted plants that compete with crop plants for soil nutrients. Chemical herbicides are the most effective immediate solution to most weed problems. Use of chemicals, however, can be harmful to wildlife, to the environment and to humans. Chemicals are also expensive, and weeds develop resistance to the chemicals. For these reasons, there is now a move toward alternative methods of controlling the weeds. One of the most promising is biological weed control, which involves using one living organism to control the activities of another organism.

Emphasis of present day agriculture is to produce more with lesser land, water and man power. Apart from natural calamities like drought, flood etc., biotic stresses like pests, diseases and weeds also influence the crop productivity greatly. Sixty to eighty per cent of the total crop losses are attributed to the devastations caused by pests and diseases. Farmer’s income in recent years is decreasing gradually due to increased cost of inputs particularly in plant protection. The excessive dependence on chemical pesticides leads to the development of resistance in insect pests and pathogens, out breaks of secondary pests and pathogens / biotypes and occurrence of residues in food chain. To avoid this situation the concept of Integrated Pest Management (IPM)/ Integrated Disease Management (IDM) approach should be considered on top priority.

Sustainable agriculture or organic farming wherein biological inputs are maximum and chemical inputs are minimal, is drawing the attention of farmers across the world including India. For replacing chemical fertilizers, which supply plant nutrients by organic manure, the basic requirement is the availability of raw material i.e. the organic matter or biomass that can be decomposed to organic manure. The question that is often asked is what are the different sources of available biomass and how much of it is available? Different sources of biomass can be categorized as

Phosphorus is one of the essential nutrients for plant growth. It is an integral part of the cellular activities of the living organisms. It has a defined role in plant metabolism such as cell division, development, photosynthesis, break down of sugar, nutrient transport within the plant, transfer of genetic characteristics from one generation to another and regulation of metabolic pathways. Phosphorus is a frequently limiting macronutrient next only to nitrogen for plant growth and makes up about 0.2% of plant dry weight. The plants obtain their P requirement from the soil pool. It occurs in soil as inorganic phosphates, produced by weathering of parent rock or as organic phosphate derived from decayed plant, animal, or microorganisms.

The term micropropagtion is also known as tissue culture. Micropropagation refers to aseptic culture of various plant parts in artificial growth medium to produce new plant. This means is recently applied in propagation of horticultural crops e.g. Orchid, banana, strawberry, papaya, grape and many other plants.

Requirements for tissue culture: It includes basic facilities including equipment, asepsis, culture medium and culture environment.

• Basic facilities including equipment: Provision of working space, large sinks, washing machine to wash glassware, oven, dryers, dust free storage, space for glass house and chemicals, autoclave for sterilizing media, solutions, water culture and instruments, supply of distilled or deionized water and various essential instruments and appliances.

The microscopic features reveals that wood is composed of minute units called cells. The fundamental differences between different kinds of woods are founded on the types, sizes, proportions, pits and arrangements of different cells that compose the wood. Softwoods have a simpler basic structure than do hardwoods due to the presence of only two cell types, and relatively little variation in structure within these cell types. Hardwoods have greater structural complexity because they have both a greater number of basic cell types and a far greater degree of variability within the cell types. In each case, however, there are fine details of structure that could affect the use of a wood.

The structure of a typical softwood is relatively simple. The axial or vertical system is composed mostly of axial tracheids, the radial or horizontal system and the rays, are composed mostly of ray parenchyma cells. According to estimates, 1 cubic metre (about 35 cubic feet) of Spruce wood contains 350 billion to 500 billion cells. The basic cell types are called tracheids, vessel members, fibres, and parenchyma

The structure of a typical hardwood is much more complicated than that of a softwood. The axial or vertical system is composed of fibrous elements of various kinds of vessel elements in various sizes and arrangements, and axial parenchyma cells in various patterns and abundance. Like softwoods, the radial or horizontal system are the rays, which are composed of ray parenchyma cells, but unlike softwoods, hardwood rays are much more diverse in size and shape.

Year         Milestones

1951       :    First amino acid was sequenced by F. Sanger and H. Tuppy.

1953    :    J.D. Watson and F.H.C. Crick proposed that DNA is a double helix.

1958    :    Discovery of DNA polymerase by Kornberg’s group and DNA replication studies began.

1959    :    Isolation of RNA polymerase.

1970    :    Discovery of reverse transcriptase showed that RNA can act as the template for the transcription of DNA and opened the way for cloning using cDNA libraries.

1970    :    General method was developed by M. Mandel and A. Higa for introducing DNA into cells by calcium dependent method.

1970    :    G.H. Khorana synthesized an artificial gene from DNA nucleotides.

1971    :    Restriction endonucleases for mapping DNA was first used by K. Danna and D. Nathans.

1972    :    The recombinant DNA Era begins. J. Mertz and R.W. Davis used T4 ligase to join DNA molecules.

Horticulture includes fruits, vegetables, floriculture, spices, tubers, plantation crops, medicinal and aromatic plants and mushrooms. The sector has established its importance in improving land use, promoting crop diversification, generating employment and above all providing nutritional security to the people. Even though India is the second largest producer of horticulture produces in the world, our per capita consumption of fruits and vegetables are very low.

Cultivated plants in general including the spice crops observed today have been evolved through selections from their weedy and wild types. Apart from this, there had been another force which could bring the wild forms into cultivated forms named human intervention which is actually the process of domestication. Natural mutations and genetic recombination after selfing and crossing also played a significant role in the entire process. Whereas, natural forces take a long time to come into act, the techniques of plant breeding was devised and fine tuned throughout passing of times, essentially to accelerate the speed of evolution using these natural phenomenons. It was, therefore, mandatory for us to know the modes of reproduction and pollination to create variability in natural population and make all thise happen to what we see today in organised cultivated forms. Moreover, knowledge on reproduction of different plant species helps the breeder to choose the right breeding procedure to be used for crop improvement. Modes of reproduction help to evaluate the genetic constitution of crop plants by determining the extent of homozygosity or heterozygosity which, in turn, are unanimously applicable to any plant. To comprehend modes of reproduction in spice crops effectively, understanding about the floral biology is absolutely necessary. Plant reproduction, a process by which one species gives birth to its offsprings, may be of two types

MOLECULAR BREEDING

Molecular breeding is the application of molecular biology tools, often in plant breeding.

Genetic markers

Genetic marker is defined as a gene whose phenotypic expression is usually easily discerned, used to identify an individual or a cell that carries it, or as a probe to mark a nucleus, chromosomes or locus (King and Stansfield, 1990). Three broad classes of genetic markers are morphological markers, biochemical markers and DNA or molecular markers.

(1) Morphological markers

Morphological markers are based on the visually assessable traits viz., morphological and agronomic traits. However, they are limited in number.

Features of morphological markers

i.They are easy to identify, there is no need of any complex analysis. Trait of interest can be identified visually.

ii.Morphological markers are inherited qualitatively or quantitatively.

iii.Frequency of availability of morphological markers is less in number i.e., morphological markers may not be available for all the traits of interest.

iv.They are influenced by environment.

v.Since they are influenced by environment, they are unstable in inheritance.

vi.They are stage specific i.e., a particular marker will be useful to identify in a particular stage of plant and not any stage of the plant.

vii.They are influenced by genotype and developmental stages of the plant.

Besides drawbacks, the morphological markers are useful to the plant breeders for the selection purpose in certain situation.