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Guava is native to tropical America, commonly known as ‘Apple of Tropics’ and it has got much greater health benefits than apple, therefore, it is also known as ‘Poor man’s Apple’. It is widely grown in the tropics, enriching the diet of million of people in the world. Guava has spread widely throughout the world because it thrives in a variety of soils, propagated easily and bears fruit relatively quickly in comparison with other fruits. At the beginning of the 16th century the Portuguese introduced it throughout the Pacific as far as the Philippines and the Spanish took it to India. 

Hazelnut is also known as a cob nut or filbert nut according to species. The hazelnut was native to the Black Sea coast long before our era, where it was found growing wild. Turkey is one of the few countries in the world having a favourable climate for hazelnut production. Hazelnuts are extensively used in confectionery to make praline and also used in combination with chocolate for chocolate truffles and products such as Nutella. Hazelnut oil recovered from hazelnuts is strongly flavoured and used as cooking oil. Hazelnuts are a good source of energy with 60.5 per cent fat content. Hazelnuts have been ranked as one of the most nutritious nuts because they supply significant amounts of protein and fiber, vitamin E and B, minerals like iron, zinc, calcium, magnesium and potassium. 

Jackfruit is believed to be indigenous to the rain forests of the Western Ghats of India and the name “Jack fruit” is derived from the Portuguese word Jaca, which in turn, is derived from the Malayalam language term, Chakka. The jackfruit has played a significant role in Indian agriculture for centuries. Archeological findings in India have revealed that jackfruit was cultivated in India 3000 to 6000 years ago. During the season, each tree bears as many as 250 large fruits, supposed to be the largest tree-borne fruit in the world. The fruit varies widely in size, weigh from 3 to 30 kg and has oblong or round shape measuring 10 cm to 60 cm in length and above 25 to 75 cm in diameter. 

Jamun is tall evergreen tree indigenous to India.  According to Hindu tradition, Rama subsisted on the fruit in the forest for 14 years during his exile from Ajodhya, because of this, many Hindus regard jamun as a ‘Fruit of the Gods’. It is known by different names in different regions of India: these names are java plum, black plum, jambul and Indian blackberry. Though the fruits of jamun are liked by all and sell at a good price, but it has still not grown as an orchard tree and is generally known as an avenue tree or as a wind break. Jamun is a hardy fruit plant which can be grown under adverse soil and climatic conditions. It is one of the hardiest fruit tree and best suited for wastelands. It is drought tolerant and at the same time can tolerate water stagnation as well as marshy wetlands. 

Kiwifruit or Chinese gooseberry (Actinidia deliciosa) is known as ‘China’s miracle fruit, and ‘the horticultural wonder of New Zealand’. From China it spread to New Zealand where it was recognized as a potential fruit and became a popular backyard vine. The name “Kiwifruit” comes from the Kiwi, a brown flightless bird and New Zealand’s national symbol. It has a fibrous, dull brown-green skin and bright green or golden flesh with rows of tiny, black, edible seeds. The fruit has a soft texture and a unique flavour and today it is a commercial crop in countries like Italy, China, and New Zealand. It is native to Southern China, where it was known as Yang Tao (sunny peach). It is known as “Chinese Gooseberry”, because of its visual resemblance to gooseberry.

Litchi (Litchi chinensis Sonn.) a native of China, is grown in India since 18th century. It is member of the genus Litchi in the soapberry family, Sapindaceae. The name of the fruit is derived from the Chinese word lee chee which means “one who gives the pleasures of life”. Litchi is also known as the “fruit of romance” in China. The most important use of litchi is as table fruit in ripe form although it is also used in processed forms such as squash. The fresh fruit has a “delicate, whitish pulp” with a “perfume” flavour. Eating litchi can benefit those suffering from colds, fever and sore throats. Great source of Vitamin C and potassium, it also contains phosphorous, calcium, magnesium and protein. According to a Chinese book, the nature of the flesh of the litchi is warm and it can helps improveing the blood circulation. The Chinese also use litchi for medicinal purposes and for making wine. 

The Loquat is a fruit of south eastern Chinese origin and it is comparable with its distant relative, the apple, in many aspects such as high sugar, acid and pectin contents. It is mostly eaten as a fresh fruit and it mixes well with other fruits in fresh fruit salads. Pies or tarts are made from firm, slightly immature fruits. A major part of total produce is used for fresh consumption, however, it can also be used for making value added products like jelly, jam, preserves, juice and squash.  Loquat syrup is used in Chinese medicine for soothing the throat like a cough drop. The flowers are regarded as having expectorant properties. It is good source of vitamin A, potassium, fiber, carbohydrates and is low in cholesterol. 

Mango is the national fruit of India which has been cultivated in India from time immemorial. It is indigenous to India and dates back to around 4000 BC. The wild mango is said to have been originated in the foothills of Himalayas in India and Burma. The mango was cultivated as early as 2000 BC. Gradually, the wild mango developed into an exotic, richly flavoured succulent fruit that is enjoyed even today. In the early stages of domestication, fruits were probably very small and fibrous without much flesh. The Mughals and Portuguese selected and grew mango plants for generations. Centuries of development have produced varieties of mangoes free from both fibre and unpleasant flavour. This eventually led to larger fruits with thick flesh that we are familiar with today. The Chinese traveler Huien T’sang, who visited Hindustan between 632 and 645 A.D., was the first person, so far as known, to bring the mango to the notice of the outside world.

Mangosteen named after the French priest and explorer Laurentiers Garcin is thought to have originated in Southeast Asia. It was said to be Queen Victoria’s favourite fruit. The correlation of Queen Victoria with the mangosteen is probably related to the fact that numerous people have referred to it as the “Queen of Fruits”. It is one of the most praised tropical fruits and certainly the most esteemed fruit. Most people enjoy mangosteen and the fruit now categorized as a “super fruit” has a ready market in western countries where it is considered a tropical delicacy. Mangosteen is primarily consumed as a fresh fruit.

The olive is native to the Mediterranean region, tropical and central Asia and various parts of Africa. Historically, olive tree was symbol of ‘Peace and Goodwill’. Olive oil has long been considered sacred; it was used to anoint kings and athletes in ancient Greece. It was burnt in the sacred lamps of temples as well as being the “eternal flame” of the original Olympic Games. Olive oil produces many health benefits when used in cooking or when poured over salads. The use of olive oil can improve digestion and can benefit heart metabolism through its low content of cholesterol. Experts claim that olive oil consumption can cause a person to grow shiny hair, prevent dandruff, wrinkles, dry skin and acne, strengthen nails, stop muscle aching, lower blood pressure and cancel out the effects of alcohol. The nutritional value of olives also includes the high vitamin E content. Olives also have high amounts of polyphenols and flavonoids which also act as antioxidants. Apart from this olives are good source of iron, copper, and dietary fiber. 

The papaya, papaw or pawpaw is the fruit of the plant Carica papaya, commonly known as ‘melon tree’ in the genus Carica. It is native to the tropics of the America. This highly loved tropical fruit was reputably called “The Fruit of the Angels” by Christopher Columbus. Papaya is considered powerhouse of nutrients as it is rich in anti-oxidants, vitamins viz. A, B, C, minerals like potassium and magnesium and fiber. Together, these nutrients needed for function of a healthy immune system, promote the health of the cardiovascular system and also provide protection against colon cancer. In addition, papaya contains the digestive enzyme, papain, which helps in digestion and is widely used in industry for various purposes. 

The purple passion fruit (Passiflora edulis) is a native of the rainforest margins in the Amazon region of Brazil. Passion fruit acquired its name from Spanish missionaries who thought that parts of the plant’s flower resembled different religious symbols such as the crown of thorns. Passion fruit grows on a vine in tropical regions. It has a tough, smooth, waxy rind that can be either yellow or purple. The flavour is like a cross between melon and guava. Passion fruits get sweeter as they shrivel. The fruit will quickly turn from green to deep purple (or yellow) when ripe and then fall to the ground within a few days. They can either be picked when they change colour or gathered from the ground each day.

The word persica, along with the “peach” itself and its cognates in many European languages, derives from an early European belief that peaches were native to Persia. Alexander the Great and his armies found the peaches in Persia and brought them to Greece. Most of the peaches grown in commercial orchards today are fruits that are harvested while too firm with a seed that clings to the pulp called a “clingstone” peach. The best flavoured peaches ripen soft and the seed easily separates from the edible portion, and these are called “freestone” peaches.

Chinese pear (Pyrus pyrifolia) is a pear tree species native to China, Japan and Korea. The tree’s edible fruit is known by many names, including Asian pear, nashi or nashi pear, Korean pear, Japanese pear, Taiwan pear, sand pear or apple pear. In South Asia, the fruit is known as Nashpati. The tree is a popular symbol of spring in East Asia and is a common sight in gardens and the countryside. The European pear (Pyrus communis) is a species of pear native to Central and Eastern Europe and Southwest Asia. The European pear is one of the most important fruit of temperate regions.

The English term pecan comes from the Algonquian Indian word paccan or pakan, meaning a nut so hard that it had to be cracked with a stone or a nut requiring a stone to crack. Pecan nut is native to North America and United States produces about eighty per cent of the world’s pecans. The Spaniards called it a “type of walnut”. Subsequently, the French turned it into “La Pacaniere”. Eventually, the name pecan nut was created. The nuts of the pecan are edible, with a rich buttery flavour. They can be eaten fresh or used in cooking, particularly in sweet desserts.

Japanese persimmons were introduced into the United States from Japan by Admiral Perry who discovered the fruit growing on the coast of Southern Japan in 1851. It is regarded as the national fruit of Japan and several improved cultivars have been developed there. It is the one of the easiest tree fruits to grow in the home landscape and also the most beautiful especially in fall when the foliage turns to brilliant colours and huge orange fruits hang from the tree like ornaments.

Pineapple is the second most popular tropical fruit next to bananas. It is also known as Piña, Nanas and Ananas. Native to South America, it was named for its resemblance to a pine cone but it is neither a pine nor an apple. When Christopher Columbus made his second voyage to the Caribbean’s in 1493, he and his crew ate the unusual fruit they found there. They thought the fruit looked like a pine cone, so they dubbed it the “Pine of the Indies.” When they introduced it to the English later on, they added the word “apple” because they thought it should be associated with another delicious fruit that people enjoyed. Thus, the name “pineapple” came into existence. In their natural form, every variety of pineapple has a rough, diamond-pattern skin. Their tastes vary slightly, though they all basically have the same juicy, tart taste. 

A plum or gage is a stone fruit tree in the genus Prunus. The European plum is thought to have been discovered around two thousand years ago, originating in the area near the Caspian Sea, while Japanese plums actually originated in China. However, they derived their name from the country where much of their cultivation and development have occurred. Mature plum fruit may have a dusty-white coating that gives them a glaucous appearance and is easily rubbed off. This is an epicuticular wax coating and is known as “wax bloom”. Plum fruit tastes sweet and/or tart; the skin may be particularly tart. It is juicy and can be eaten fresh or used in jam-making or other recipes. Plum juice can be fermented into plum wine; when distilled, this produces a brandy known as Slivovitz or Rakia in Eastern Europe. Dried plums (or prunes) are also sweet and juicy and contain several antioxidants. 

Pomegranate commonly known as ‘anar’ is an ancient favourite table fruit of tropical and sub-tropical regions of the world.  The pomegranate tree is native from Iran to the Himalayas in northern India and has been cultivated since ancient times throughout the Mediterranean region of Asia, Africa and Europe. The word pomegranate comes from the Latin “Pomum granatum” which means “apple of many seeds.” The Romans called it the Punic apple. Ancient Romans not only enjoyed the succulent flesh of this fruit but due to the high amount of tannic acid in the skins, they also used the skins in the process of tanning leather. Perhaps due to the fruit’s princely blossom crown, it has gained distinction as a royal fruit. “Pomum granatum” or seeded apple was the name which was known in the middle ages. The French named their hand-tossed explosive a grenade after the seed-scattering properties of the pomegranate fruit.

Raspberries are grown for the fresh fruit market and for commercial processing. There are many species of raspberry but the name originally referred with the red fruit to the European species Rubus idaeus. The English name comes from an old English term “raspis”, which refers to the slightly hairy or “rasping” surface of the fruit. The raspberry can be of any colour from orange, pink, red, purple to black. Rubus albescens also known as Mysore raspberry is native to India. It is also called Snowpeaks, Ceylon or Hill raspberry. 

Sapota or sapodilla popularly known as Chiku is native to tropical America where it is mainly grown for its chickle, “the gutta parcha” extracted from its latex from stems. It is used as a base material in chewing gum and in some other industrial uses. However, in India it is cultivated for its delicious sweet fruits. The fruit is fleshy berry, variable in shape, size and weight. The skin is thin, rusty brown somewhat scurfy looking like Irish potato, and the pulp soft, melting, crumbling with a sandy or granular texture with 1–5 hard black seeds. The fruit has an exceptionally sweet malty flavour. 

Strawberries one of the best fruits of the world are native to North America. Strawberry fruits are aggregates made up of several small fruits, each with one seed called an achene. The flesh of the strawberry is actually an enlarged receptacle, non-reproductive material. The word strawberry comes from the old English streawberige, most likely because the plant sends out runners which could be linked to pieces of straw. The name Strawberry was also derived from the berries that are “strewn” about on the plants, and “strewn berry” eventually became “Strawberry”. Strawberry is a delicious fruit taken fresh in several ways. It also makes excellent ice cream and jam on account of its rich aroma. 

The English walnut (Juglans regia) is a native of Western and Central Asia. The nut was the food of the royalty and was introduced by the Greeks in Rome, where it became Juglans, a name derived from Jovis and glans, meaning Jupiter’s Acorn or the ‘Nut of the Gods’. The English walnut tree, also known as the Common, Persian or Royal walnut tree, is an ancient tree with many uses, most notably for its use as timber and for the walnut fruit. The common walnut tree has been used as a food, beauty aid, medicine and natural health supplement. In China the tree is used horticulturally in classical garden design.

Food security of a country can be achieved through advanced agricultural research, followed by efficient and effective transfer of technologies. Unlike laboratory experiments, agronomic experiments are being conducted at open environment which leads to lot of variations in outcome/results due to influences of unpredictable weather condition and heterogenic soil characters even though proper adoption of local control. Results of an experiment can be expressed in different ways to make the clients to understand easily recordable output data viz., growth attributes, yield parameters and yield, laboratory analyses data like soil and crop nutrient status and quality parameters of the produce. Nutrient management studies should focus the efficiency of particular fertilizer nutrient over others, methods of fertilizer application, contribution of nutrients to crops from soil and fertilizer etc. Similarly, water management experiments would explain the water conveyance, application and storage efficiencies, suitability of method of irrigation, water saving techniques and water use efficiency of different crops as well as agronomic practices etc. In weed management experiments, the efficiency of particular herbicide in terms of controlling weeds, and increasing crop yields have to be expressed by various efficiency indices. Weed suppression ability of an intercrop can be explained by smothering efficiency.

2.1. Rainfall

Rainfall is one of the prime natural resource that decide the economy of a country. Inadequate and improper distribution of rainfall during cropping period will have serious threat to crop production resulted in food insecurity of growing population. So each and every action must be focused to conserve every drop of rainfall in an effective way and the conserved rainfall should be utilized in an efficient manner for crop production.

3.1. Growth Analysis

Growth and development analysis of plants provides information related to influence of various factors either negative or positive on plant growth. The basic idea of this analysis is the estimation of crop growth at various stages and finally towards the yield. It will help us to understand the performance of a genotype as well as impact of agronomic practices on the crop at any stage of growth and also on final yield. This would also identify the factors responsible for high yield and thereby provide the basis to tailor agronomic practices. The most common parameters used in growth analysis are leaf area index, crop growth rate, relative growth rate, net assimilation rate and leaf area duration.

Importance of nutrient management in crop production can be very well explained by conducting various field trails by different fertilizer nutrient, methods of application and sources of fertilizer. Experiments on nutrient management are being carried out to study the impact of nutrient application, new techniques of fertilizer application, sources and doses of fertilizers on plant growth, yield and soil fertility and their efficiency over existing one was elucidated through various efficiency indices. The following efficiencies are normally being used in nutrient management studies.

Agricultural water consumes about 85% of the available water. The future hopes to solve world’s food problem lies in irrigation development. Considering the need of efficient management of water, which is crucial at this point understanding of different efficiencies of the irrigation related experiments or projects, is necessary. Irrigation efficiency is used to evaluate how effectively the available water is used in crop production. Water is conveyed through canal system, watercourses and channels to crop fields. Irrigation is applied to store water in the effective root zone of soil for use of crops. A considerable loss occurs after its diversion from sources to its actual use by crops. The extent of water loss in the process decides the irrigation efficiency. Irrigation efficiency declines as the water loss increases. A high efficiency of an irrigation project is always desirable. The efficiency may be estimated for various operations beginning from diversion of water to its actual use by crops, uniformity in its distribution in the root zone, its use for crop productivity, economics and so on.

Weed management practices are evaluated for its efficiency in terms of effective control of weeds and economics of control measures through various indices under sole crop situation as well as intercrop situation.

6.1. Indices for Sole Crop Situation

The absolute effect of particular method or a chemical in reducing the weed competitions and increasing the crop productivity are measured effectively by various indices. The comparisons of weed control methods are usually based on the yield, weed population and weed dry matter from the control as well as treated plots.

Comparison of different cropping systems with reference to land use and yield advantages is possible through various efficiency indices. The various cropping and farming systems practiced in an area have to be properly evaluated to decide their suitability and relative advantages. The comparisons can be made with reference to many factors viz., yield, monetary, water use efficiency, nutrient use efficiency, total dry matter production, intensity of land use etc., The cropping as well as farming systems research are being perused at national level with major focus for identification of location specific efficient systems since 1990. However, on perusal of research publications we find that the data of cropping systems are interpreted in different ways with major focus only on production and net return on hectare basis. In fact, these two aspects are not the indicator of the efficiency of a particular system. Many advances have been made in recent years to identify the efficient system for a particular location. Some of the methodologies, which are of concern to crop scientists in general and agronomists in particular, are highlighted here for ready reference to the researchers, agronomists and crop planners. Different indicators of system efficiency are as follows (Gangwar et al., 2003).

The thrust of Indian Agriculture in the post green revolution period was an enhancing agricultural productivity through sustainable practices. In order to achieve its, the government of India implemented a national level programme for the development of rainfed areas through the watershed approach. A watershed is a community-based programmes that is organized in a specifically earmarked area with a defined time frame and focuses on a wide range of issues and activities for integrated development of the village. The main focus is laid on water, food and fodder security and employment generation

The watershed approach aimed at augmentation and stabilization of production and productivity, minimizing ecological degradation, reduction in regional disparity, opening up of greater opportunities for employment of rural poor in the rainfed areas. A similar approach has been adopted for developing the more resource poor areas — drought prone, desert and wastelands — and to provide sustainable means of livelihoods to the rural poor in these areas. Promotion on the economic development of the village community, optimum utilization of the watershed’s natural resources like land, water, vegetation, employment generation and development of the human and other economic resources of the village and encourage restoration of ecological balance in the village are the main objectives of watershed development programmes.

Cost of Cultivation

The expenditure incurred from sowing to harvest including the field preparation can be worked out and expressed in Rs. ha^-1.

Gross Return

Total income obtained from multiplication of unit cost of main product as well as byproducts and its total yield and expressed in Rs. ha^-1.

Net Return

Net return is obtained by subtracting cost of cultivation from gross return and expressed in Rs. ha^-1.

Net return = Gross return – total cost of cultivation

Agronomic Research

Statistical tools are used in all branch of agriculture. It is mainly used for efficient planning of experiments and for interpreting experimental data. A good researcher should be aware of statistical techniques, which helps not only summarization of data but also interpretation of data.

10.1. Parameters Used in Statistics

Population

The aggregate or totality of all possible objects possessing the specified characteristic is called a population. Thus, a population may consist of all plants in a plot or field.

Sample

A portion of the population is known as sample. For statistical inferences about a population from a sample, it is essential that the samples are representative of the population.

Biotechnology plays a very important role in agriculture as a result of its ability to modify microorganisms, plants, animals, and agricultural processes. The umbrella of microbial technology in agriculture covers numerous scientific activities, ranging from production of biofertilizers to that of microbial pesticides; from biological nitrogen fixation to lignocellulose degradation; from production of biomass and biofuels to transgenic plants. Terrestrial ecosystem contains an important dynamic living matrix termed soil, which is critical for agricultural production and food security. Soil forms the medium for growth and maintenance of a variety of plant species. Soil is considered a store house of microbial activity, though the space occupied by living microorganisms is estimated to be less than 5% of total space.

The term soil refers to the outer, loose material of the earth’s surface, a layer distinctly different from the underlying parent rock. A number of features characterize this region of the earth’s crust. It is the natural medium, which supports plant growth. It provides the physical support needed for the root system and also supplies nutrients needed for plant growth. It is a perennial source of organic matter. It supports a vast population of microorganisms.

Nitrogen is the most important element on which depends growth and productivity of plants. It is also the most abundant molecule in the atmosphere (80%), yet it cannot be utilized by plants. The plant utilizable form of nitrogen is either, its most oxidized form, the nitrates or the most reduced state, the ammonia.  The indiscriminate use of nitrogenous fertilizers amounts to depletion of non-renewable fossil fuels used in fertilizer production. Sustainable agriculture depends largely on renewable resources and on-farm nitrogen contributions are achieved largely through biological nitrogen fixation (BNF), which helps in maintaining and/or improving soil fertility by using atmospheric nitrogen. Annually BNF is estimated to be around 175 million tonnes of which close to 79% is accounted for by terrestrial fixation.

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 rhizosphere is the narrow zone of soil surrounding the root that is under the immediate influence of the root system. This zone is rich in nutrients when compared with the bulk soil, due to the accumulation of a variety of organic compounds released from roots by exudation, secretion and deposition. Organic compounds released by plant roots include amino acids, fatty acids, nucleotides, organic acids, phenolics, plant growth regulators, putrescine, sterols, sugars and vitamins. Because these organic compounds can be used as carbon and energy source by microorganisms, microbial growth and activity is particularly intense in the rhizosphere.

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.

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.

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

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.

1. Damping-off
Pathogen
Pythium aphanidermatum (Edson.) Fitz.
P. debaryanum                  
Rhizoctonia solani Kuhn.
Fusarium spp.
Sclerotium spp.
Symptoms
Damping-off of onion seedlings occurs in two stages:
    (i)    Pre emergence
(ii)    Post emergence
In pre emergence stage, plumules are killed before they reach the soil surface. They may be infected, killed even before the hypocotyls have broken the seed coat.

Vegetables
Peas
1. Rust
Pathogen
Uromyces fabae (Pers.) de Bary
Symptoms 
The fungus produces characteristics rust pustules on the host. Pustules are mostly found on the leaf blade, though often they may be found on the petiole and stem of pea plants. The sori are small, roundish, open, and powdery as well as brown coloured. In severe infections, the leaf may wither, resulting in considerable damage to the crop. As the plants near maturity, the fungus produces the telial stage on the host.

Tomato
1. Damping off
Pathogen
Pythium aphanidermatum
Fusarium spp.
Sclerotium spp.
Symptoms
Damping off is the most important disease of tomato. Several seed and soil borne fungi can kill before the tender redical and plumule establish in the nursery bed. The pre emergence damping off and seed rotting is the usual cause of poor seedling stand. This type of damping off causes hidden loss but the post emergence damping off is more serious problem. Seedlings get infected near the soil line (collar region) after emergence and give wire stem symptoms. The tissue become soft, water soaked and weak causing the seedlings fall over and later on they die. The entire action is so fast that leaves remain green but they are unable to stand further.

Cauliflower, Cabbage and Knol khol
1. Leaf spot
Pathogen
Alternaria brassicae (Berk.) Sacc.
Symptoms
Alternaria leaf spot usually appear in early stage in cauliflower while at later stage symptoms in cabbage appear as circular light brown spot in leaves. Concentric rings are clearly visible on the spots. In older plants on leaves, petioles and stem, brown to black circular to slightly elongated spots appear.

1. Damping off
Pathogen
Pythium spp
Phytophthora spp
Fusarium spp
Sclerotium spp
Symptoms
It is a term used to describe the damage caused by various fungi to the seed and emerging seedling in the reduced plant stand and sometimes it is so serious that  resowing becomes inevitable. Major symptoms are the failure of the seedlings decay or sudden death of the emerged seedlings roots and lower stems of emerged seedlings become soft and watery and may be reddish brown in colour.

Okra/Ladies finger/Bhindi
1. Leaf blight/Spot
Pathogen
Cercospora abelmoschi Ell. & Ev.
Symptoms
The fungus grows as shooty to dark olivaceous, ectoparasite covering entire leaf lamina. Pathogen initiates as small isolated fungal growth on lower side of leaf but very soon it spreads on both sides. Pathogen reduces severely the photosynthesis area. Infected leaves fall down very quickly after dropping and rolling. It causes severe loss in seed production crop as well as in the late sown crops.

Abstract

Knowledge of  seed biology is crucial for proper management of  seed sources as well as the handling of seeds. In broadest sense seed technology includes the development of superior crop plant varieties, their evaluation and release, seed production, seed processing, seed storage, seed testing, seed certification, seed quality  control, seed marketing and distribution and research on various aspects. Vegetative propagation has also become popular for the propagation of some tree species, but seed propagation remains the principal mode of propagation in both the temperate and the tropical region. Forest plantations are a powerful tool in the continuing efforts of foresters to increase productivity per unit area apart from mitigating the climate change and global warming issues. Hence to improve the existing stock in terms of yield, quality, disease resistant and desired traits, seed technology can play a major role in providing quality genetic material.