eChapters

To Estimate the DNA Using Diphenylamine

Introduction

DNA estimation is helpful to know about the total amount of DNA of prokaryotic as well as eukaryotic system. One method used for DNA estimation is Diphenylamine assay, is that of Burton who modified the original procedure of Dische. This procedure is based on treatment of nucleic acid with hot perchloric acid to hydrolyze DNA nucleotides. Diphenylamine reacts specifically with deoxyribose in DNA to form a blue-colored complex. Since diphenylamine does not react with ribose, one can assay for DNA in the presence of contaminating RNA.

Principle

The DPA method is based on the colorimetry measurement of products formed by the reaction of ù- hydroxylevulinaldehyde (from the deoxyribose released after depurination of DNA) with diphenylamine in 2.5 N perchloric acid.

When DNA is treated with diphenylamine under acidic condition (PCA) a blue complex is formed with a sharp absorption maximum at 595 nm (600 nm). In acid solution, the straight chain form of the deoxypentose is converted to highly reactive ω – hydroxylevulinaldehyde that reacts with diphenylamine to give blue complex. The reaction yields two mixture of product which together have absorbance maximum at 595 nm (600 nm). Interferences include proteins, lipids, saccharides and RNA. In DNA the only deoxyribose of the purine nucleotides reacts, so that the value obtained represents half of the total deoxyribose present.

Introduction

DNA denaturation, also called DNA melting, is the process by which double-stranded deoxyribonucleic acid unwinds and separates into single-stranded strands during the breaking of hydrogen bonding between the bases. Both terms are used to refer to the process as it occurs when a mixture is heated, although “denaturation” can also refer to the separation of DNA strands induced by chemicals like urea. For multiple copies of DNA molecules, the melting temperature (T_m) is defined as the temperature at which half of the DNA strands are in the double-helical state and half are in the “random-coil” states. The melting temperature depends on both the length of the molecule, and the specific nucleotide sequence composition of that molecule.

Applications of DNA Denaturation

The process of DNA denaturation can be used to analyze some aspects of DNA. Because cytosine / guanine base-pairing is generally stronger than adenosine / thymine base-pairing, the amount of cytosine and guanine in a genome (called the “GC content”) can be estimated by measuring the temperature at which the genomic DNA melts. Elevated temperatures are associated with high GC content. GC ratios within a genome are found to be markedly variable. These variations in GC ratio within a genome of higher organisms results in a mosaic like formation with islet regions called isochores. This results in the variations in staining intensity in the chromosomes. The isochores include in them essential protein coding genes, termed housekeeping genes and thus determination of ratio of these specific regions contributes in mapping these essential genesbacterial systematics has recommended use of GC ratios in higher level hierarchical classification. For example, the Actinobacteria are characterised as “high GC-content bacteria”. In Streptomyces coelicolor A3(2), GC content is 72%. The GC-content of Yeast (Saccharomyces cerevisiae) is 38%, and that of another common model organism Thale Cress is 36%. Because of the nature of the genetic code, it is virtually impossible for an organism to have a genome with a GC-content approaching either 0% or 100%. A species with an extremely low GC-content is Plasmodium falciparum (GC% = ~20%), and it is usually common to refer to such examples as being AT-rich instead of GC-poor.

Procedure

Place a portion of your RNA sample (approximately 40 mg, hydrated) into a heavy walled Pyrex test tube. Add 1.0 ml of 1 N HCl and seal the tube.

Heat the tube in a boiling water bath for 1 hour.

Cool the tube, open it and place the contents into a centrifuge tube. Centrifuge the contents at 2,000 RPM in a clinical centrifuge to remove any insoluble residue. The supernatant contains your hydrolyzed RNA.

Prepare Whatman filter paper No. 1 for standard one-dimensional chromatography.

Using a micropipette, spot 20 µl of your hydrolyzate onto the paper, being careful to keep the spots as small as possible (repeated small drops are better than one large drop). Allow the spots to completely dry before proceeding.

Place the paper chromatogram into your chromatography tank and add the solvent (acetic acid:butanol:water). Allow the system to function for an appropriate time (approximately 36 hours for a 20 cm descending strip of Whatman #1). Remove the paper and dry it in a circulating air oven at 40° C for about 2 hours.

Locate the spots of nucleotides by their fluorescence under an ultra-violet light source. Expose the paper chromatogram to a UV light source and outline the spots using a light pencil. The order of migration from the point of origin is guanine (light blue fluorescence), adenine, cytilic acid and finally, uridylic acid.

After cafefully marking the spots, cut them out with cutters and place the paper cut outs into separately labeled 15 ml conical centrifuge tubes. Add 5.0 ml of 0.1 N HCl to each tube and allow the tubes to sit for several hours to elute the nucleotides from the paper.

Introduction

Yeast contain a hard cell wall. Spheroplasts are yeast cells where the cell wall has been enzymatically degraded. These spheroplasts are very fragile so we must be careful with them. Once we have spheroplasts it will be very easy to lyse the yeast cells and quickly release the RNA and proteins in the cell into a controlled environment where we can temporarly keep the cellular RNases from degrading the RNA. We don’t want to lyse the cells before they are in this controlled environment.

Growth of Yeast Cultures

Cultures of wild-type and yeast containing various mutations will be grown up the day of the experiment. Each section will be given one wild type yeast culture and a culture containing one of the mutant varieties that we have discussed in class.

Yeast are grown very similarly to bacteria. Like bacteria, they have different stages of growth. Scientists divide these stages of growth into early-log phase, mid log-phase, late log-phase, and the stationary phase. These phases are based on the amount of yeast that are around in the broth and how quickly they are able to grow and divide based on nutrient use. Reading the absorbance of the sample at 600 nm is a way in which you can determine what phase of the yeast growth series you are in and how many cells you have.

Haploid yeast cells contain approximatley 1.2 pg of RNA per cell

Predict approximatly how much RNA you should isolate

1. Bacterial (Prokaryote) Genome

The chromosome of most bacteria is a single super coiled double stranded circular DNA molecule. A complex packaging mechanism is necessary in order to ensure that the entire DNA is folded within the bacterial cell in a manner, which will not inhibit transcription nor allow entanglement of the two daughter strands to occur during replication (Highly condensed >10 mg/ml in region less than l ìm in diameter). This is achieved by two main mechanisms.

• First the DNA is folded into between 40-100 loops
• Second each of the quasicircles is it self super coiled independently of the others each loop are abolished by Ribonuclease.

Deoxyribonucleic remove the super helical nature of the loops, though limited treatment with this enzyme will attack only a small number of the loops and therefore leads to removal of only some of the super coiling. The intact folded chromosome or nucleoid can be isolated in the presence of non ionic detergents and high molarities of salt in two possible forms free and membrane associated. The free form which sediments at 1600-1700s consists of about 60%DNA, 30%RNA and 10%protein the bulk of which is the enzyme RNA polymerase. The membrane bound form contains an additional 20% of membrane-attached protein. Bacterial genome size ranges from 580 to 9900kbp, & the average gene size is constant from 900 to 1100bp of which 87-94% are protein coding (Rickettisa’s 76% and Borelia Plasmid’s 41% are exceptions).

DNA Migration in Agarose and Polyacrylamide Gels

Recommended Gel Percentages for Separation of Linear DNA

Mole (mol)

1 mole of any substance contains 6.02 x 10²³ units. The number of moles in a given weight of substance can be calculated using following equation.

1. pH Meter

pH meter/electrode systems are the most common method of measuring pH in the biology laboratory. Although more expensive and more complicated to use than chemical indicators, pH meters provide greater accuracy, sensitivity, and flexibility. When used properly, pH meters can measure the pH of a solution to the nearest 0.1 pH unit or better, and they can be used with a variety of samples.

2. UV Spectrophotometer

Perhaps there is no other technique except UV-visible spectroscopy, which has been so extensively employed and has such a profound impact on progress in biochemical investigations. UV-visible spectroscopy has undoubtedly become an indispensable tool and is routinely used for identification and quantitative estimation of most of the biomolecules. Besides other applications, most of the enzyme assays and the screening of biomolecules recovered in different fractions by separation processes such as column chromatography, density gradient centrifugation etc, rely heavily on spectrophotometer or colorimetric technique.

Search for genetic material—nucleic acid or protein/DNA or RNA?

• Griffith’s Transformation Experiment
• Avery’s Transformation Experiment
• Hershey-Chase Bacteriophage Experiment
• Tobacco Mosaic Virus (TMV) Experiment

Timeline of Events

• 1890 Weismann - substance in the cell nuclei controls development.
• 1900 Chromosomes shown to contain hereditary information, later shown to be composed of protein & nucleic acids.
• 1928 Griffith’s Transformation Experiment
• 1944 Avery’s Transformation Experiment
• 1953 Hershey-Chase Bacteriophage Experiment
• 1953 Watson & Crick propose double-helix model of DNA
• 1956 Gierer & Schramm/Fraenkel-Conrat & Singer Demonstrate RNA is viral genetic material

BC

1750 The Sumerians brew beer.

500 The Chinese use moldy soybean curds as an antibiotic to treat boils.

250 The Greeks practice crop rotation to maximize soil fertility.

100 Powdered chrysanthemum is used in China as an insecticide.

AD: Before the 20^th Century

1590 The microscope is invented by Janssen.

1663 Cells are first described by Robert Hooke.

1675 Leeuwenhoek discovers protozoa and bacteria.

1745 Maupertuis proposes an adaptationist account of organic design

1797 Jenner inoculates a child with a viral vaccine to protect him from smallpox.

1802 The word “biology” first appears.

The Laboratory Worker is Surrounded by Many Dangers such as from..........

Handling of infectious materials.

Handling of broken glassware.

Accidental spill of corrosive reagents.

Swallowing of corrosive reagents such as concentrated Sulphuric acid,

Hydrochloric acid, sodium hydroxide, trichloroacetic acid etc.

Swallowing of infectious specimen.

Inhalation of poisonous fumes.

Infection in the conduct of necropsies.

Potential hazards in the form of inflammable chemicals and gas leakages.

Due to increase in population, rapid urbanization, industrialization and shrinking land holdings, there is tremendous pressure on availability of land resources for agriculture, which results in decreased arable land area year after year. The huge gap between present production and future requirements necessitates intensive vegetable production and availability at affordable prices. Vegetable production can be enhanced either by increasing productivity, use of improved cultivars and ago-techniques, bringing additional land under vegetable crops or by promotion of protected cultivation. By adopting protected cultivation, year round availability of quality produces both for domestic use and export can be assured.

Several biotic and abiotic stresses are the major factors responsible for low productivity and poor quality in large number of vegetable crops under open field cultivation more specifically during rainy and post rainy season. The increasing demand of off-season and high quality vegetables in various markets of the big cities had call the attention of the vegetable growers for diversification from traditional ways of vegetable cultivation to modern methods of vegetables cultivation in an agri-business entrepreneurial models. Under the new era of FDI (Foreign Direct Investment) in retail these kinds of models are having high potential for betterment of the farmers opting for quality and offseason vegetable cultivation through protected cultivation. Protected cultivation structures are useful for combating both biotic and abiotic stresses that limits the productivity and quality of vegetable crops. This requires careful planning, attention and details about timing of production and moreover, harvest time to coincide with high market prices, choice of varieties adopted to the off season environments, and able to produce economical yields of high quality produce etc.

Introduction

Organic farming per se is not a new concept rather is an age old practice of cultivation crops without synthetics. However, in modern usage it is a type of farming without synthetics but at the same time taking advantage of all the modern agriculture technologies like soil testing, nutrient management, ecofriendly pest management, etc. developing and developed world have different incentives for taking up organic farming. Growing health consciousness among the people of developed world is the prime motive behind interest in organic farming. However, conversion of “by default” organic agriculture into “certified organic” is perspective in the developing world so that farmers get price premium. Whatever the case may be, the area under organic farming as well as demand for organic food/product is increasing both in developing as well as in the developed world.

Organic production is a systems approach. Although many aspects of vegetable production remain the same in both “organic” and “non-organic” or “conventional” systems, there are differences. The major components of production which differ between these two systems include transplant production, soil fertility management, and insect, disease, and weed management. “Organic” usually refers to a crop management system that promotes biodiversity, biological cycles, and soil biological activity. Organic production concentrates on natural processes and how to manage them. Other materials and products are additions to, not replacements for, management. An organic system takes time to develop. It may be achieved in stages, for example by starting with organic soil amendments and other soil improving procedures. Then, try biological control of pests, some companion plants, etc. Eventually, the entire system will be changed. It will take years to convert to a healthy organic system.

A successful vegetable production industry is very dependent on a sustainable supply of seeds to the growers. At the present time, the seed industry plays an important role in both production and distribution of high quality vegetable seeds.

Successful seed production of a crop depends on a thorough knowledge of the reproductive process of a particular crop. The techniques of seed production must take into account several features of reproduction: whether it is sexual, asexual, or a combination of the both, the nature of floral structures, the amount of pollen transfer, the degree and means of self-incompatibility and the effect of inbreeding on vigour. For most purposes the important consideration to the seed producers is the extent of cross-pollination. It is, therefore, necessary that before engaging himself in seed production, a producer must acquaint himself with the following details of reproduction in the particular crop:

Methods of Reproduction

The method of reproduction in vegetable crop plants may be broadly grouped in to two categories, asexual/vegetative and sexual:

Improved Varieties of Tuber Vegetables

A. POTATO

Improved Varieties of Asparagus

(1) Perfection

Source : Developed at IARI, New Delhi

Maturity : Early

Spears : Large, green, succulent, heavy cropper and uniform in maturity

Production Technology of Asparagus

Climate

Asparagus is temperate season vegetable and bears excellent crop between a temperature range of 15-24ºC for most of the growing season. The ideal day temperature is 25-30^oC and night temperature 15-20^oC. It can tolerate frost up to some extent but continuous freezing is harmful for its growth. Spear initiation occurs at soil temperature of more than 10ºC. Spear elongation is faster at high air temperature. Root and shoot development is reduced below 13ºC and above 29ºC. Due to warm weather, spear tips open prematurely and quality of spears is reduced. Elevation of more than 1000m is good for high yield.

Improved Varieties of Leafy Vegetables

A. AMARANTHUS

Improved Varieties of Root Crops

A. RADISH

A. Asiatic/Tropical Varieties

Improved Varieties of Bulb Crops

A. ONION

Improved Varieties of Peas and Beans

A. VEGETABLE PEA

A. Early Varieties

Improved Varieties of Cucurbits

A. CUCUMBER, MELONS, PUMPKIN AND SQUASHES

Cucumber (Khira)

Improved Varieties of Cole Crops

A. CAULIFLOWER

Improved Varieties of OKRA (Bhindi)

Vegetable research in India is of very recent origin. Research on vegetable crops was started by ICAR with the sanctioning of a nucleus ‘Plant Introduction Scheme’ at IARI, New Delhi in 1947-48. Simultaneously, the ICAR also started such ad-hoc schemes in different states like Punjab, Uttar Pradesh, West Bengal, Maharashtra, Himachal Pradesh, Jammu & Kashmir and Tamil Nadu.

Prior to World War II, entire seeds of temperate vegetables were imported from European countries. When, during World War II, supply of vegetable seeds from Europe suffered a serious setback, the government of India felt the need for production of these seeds within the country. As a result of this, the government of India established a Vegetable Breeding Station at Katrain in Kullu Valley, Himachal Pradesh in 1949. This station was transferred to Indian Agriculture Research Institute in 1955 to undertake research on improvement of temperate vegetable crops, standardization of their seed production technology and to produce seeds of identified improved varieties of temperate vegetables. This research station is carrying out intensive research on all aspects of temperate vegetables including improvement, production technology and their seed production.

Further, a division of Horticulture was created at the Indian Agriculture Research Institute, New Delhi in 1956-57. However, vegetable research was organized on sound footing with the establishment of the Indian Institute of Horticulture Research (IIHR) at Bangalore with a full fledged Division of Vegetable Crops in 1968. The vegetable research in India received a further boost when a separate division of Vegetables Crops and Floriculture was started at IARI, New Delhi in 1970. The floriculture work was separated from the division of Vegetable Crop and Floriculture, IARI, New Delhi in 1982 and the division was then named as Division of Vegetable Crops, which was assigned the research work exclusively on different vegetable crops. In the Sixth Five-year Plan, IIHR, Bangalore started two Central Horticulture Experiment Stations, one each at Ranchi, (Bihar) and Godhra (Gujarat) to intensify research on horticultural crops in important tribal areas of the country where research on vegetable crops was also started to meet the specific requirements of these regions. Establishment of Agricultural Universities and All India Coordinated Vegetables Improvement Project gave further fillip to vegetable research in India.

Significant achievements have been made in the food availability throughout the world over the last few decades. The estimated number of people in developing regions suffering from chronic malnutrition has declined (from 946 million people in 1969-71 to 870 million people in 2010-12), as the proportion of malnourished people from 36 percent to 20 percent, even though the world population has increased. Global food supplies (if distributed according to individual requirements) are sufficient to fulfill the energy needs. An estimated 20 percent of the people in developing world are chronically under nourished, consuming too little food to meet even the minimal energy needs. Approximately 192 million children under the age of five years suffer from acute or chronic protein energy malnutrition. According to WHO, 6.9 million children under the age of five died in 2011, from direct or indirect result of hunger and malnutrition. Moreover, more than 2 billion people, mostly women and children are deficient in one or more micronutrients, babies continue to be born mentally retarded as a result of iodine deficiency, children go blind from vitamin-A deficiency and enormous number of women and children are adversely affected by iron deficiency.

The overall growth in food availability resulting from the green revolution over the last two decades has eliminated the threat of famine for India’s entire population. Country’s production of food grains has reached over 257.07 million tonnes. However, malnutrition is still a serious problem in this region. Evidences suggest that micronutrient deficiency is far more prevalent in the area than protein energy malnutrition. The International Food Policy Research Institute has reported a rising trend in micronutrient deficiencies, which is becoming more serious than malnutrition from lack of major nutrients. Thus, the emphasis is now shifting from supply of basic food (calories & protein) towards supply of balanced diet (calories, protein & micronutrients which includes vitamins and minerals).

Vegetables occupy an important place in diversification of agriculture and have played a pivotal role in the food and nutritional security of every growing population of our country. Vegetables are becoming important as cash crops for urban and export markets. Looking at the national scenario, vegetables have tremendous strength in terms of natural and genetic resources. A large number of wild taxa and indigenous germplasm are available in the country and many of them have not being fully capitalized. Though efforts have been made to tap the variability present among the vegetable crops in the country and many varieties have been released, it needs further attention so that the problems of biotic and abiotic stresses can also be minimized. The vast diversity of land, soil and agro climatic conditions prevalent in India also offers a unique competitiveness to grow wide range of vegetables. During the last four decades, India has made commendable progress in vegetable production (from 23.45 million tonnes in 1961-65 to 166.47 million tonnes in 2015-16), securing the position of second largest production of vegetables in world next only to China. The total world vegetable production is 1159.88 million tonnes from an area of 59.16 million hectares. In this, India contributes about 15.88 % with the production equal to 166.47 million tonnes from an area of 9.29 million hectares (NHB, 2015-16).

1. Potato

Scientific name: Solanum tuberosum L.

Family: Solanaceae

Origin: South America

Chromosome No.: 2n = 4x = 48

Introduction

Potato is one of the four major food crops of the world and is also a very popular vegetable crop. It is extensively cultivated in China, Russian Federation, Ukarine, Poland, Ireland, Great Britain, Germany, Netherlands, France, Spain, South America, India and USA. Potato was brought from Peru to Spain by the Spaniards in 1565 when it was widely grown in Spain and Italy. They were probably brought to England about 1586 by Sir Francis Drake. Potato was introduced in India in early 17^th century probably by the Portuguese. Now it is one of the principal cash crops of India.

Importance and use

• Potato is the fourth major food crops of the world after rice, wheat and maize.
• Being a major source of carbohydrate it is often used as a substitute for cereals.
• It is one of the major vegetable crops of the world and is grown in almost every country.
• In India, it is considered as a staple vegetable and used either alone or mixed with other vegetables.
• Potato is used as vegetable in various forms such as, boiled, mashed, baked, fried and cooked in sambar and different curries of vegetable, fish and meat.
• Potato is processed into different commercially used dehydrated, canned and fried products like, shredded potato, sliced potato, chips, flakes, French fries, finger chips, granules, disc, cubes, flour, etc.
• It is used for several industrial purposes such as production of starch, alcohol, dextrin, glucose, etc.
• Potato starch is a large grained starch and contains 25 % amylase and 73 % amylopectin and high phosphate content.

1. Seedling management in the nursery

Seedlings of many seed propagated vegetable crops like, tomato, brinjal, chillies, sweet pepper, cauliflower, cabbage, knolkhol, broccoli, Brussels sprout, kale, endive, chicory, celery, lettuce, parsley, onion, etc. are first raised in the nursery beds before transplanted in the main field although, many of these crops like, tomato, sweet pepper, onion, cabbage, cauliflower, broccoli, etc. are also direct seeded using precision seed drills in the USA, Japan, the Netherlands, Italy and other European countries. Many seed propagated vegetable crops viz., okra, peas, beans, radish, carrot, beet, turnip and all the cucurbits (e.g. bitter gourd, bottle gourd, pumpkin, cucumber, watermelon, muskmelon, snake gourd, sponge gourd, ridge gourd, etc.) are conventionally grown through direct seeding in the main field.

Transplant groups

1. Plants easy to transplant: They form new roots rapidly, put forth shoots rather slowly and absorb water readily e.g. beet, broccoli, Brussels sprouts, cabbage, cauliflower, Swiss chard, lettuce and tomato.

2. Plants transplanted with moderate ease: This group replace roots and grow shoots a bit slower than the previous group and do not absorb water very efficiently e.g. celery, brinjal, onion, pepper, leek and cauliflower.

Introduction

The book has been framed as a text book cum vegetable production manual for both under graduate and post graduate students of Agriculture/ Horticulture as well as commercial vegetable production professionals. This book has been oriented on different management practices of vegetable culture in open field condition viz., Classification of vegetable crops, Management of seedlings in the nursery, Water managent, Plant nutrient management, Pollination management, Integrated pest management, Biological management of diseases, Weed management and Production technology of different vegetable crops.

Classification of vegetable crops

Vegetables are defined as herbaceous plant origin material with generally low calorific value providing micronutrients, vitamins, antioxidants, fibre and induce alkaline reaction inside human body. Vegetable crops are not only botanically different but also their cultural and climatic adaptation shows wide variability. It is, therefore, necessary to classify the vegetable crops for their easy recognition. Vegetable crops can conveniently be classified “Botanically” for the purpose of vegetable breeding and according to “Method of culture” from the point of crop husbandry.

Botanical classification

The crops used for vegetable purpose in the world belong to 1200 species under 78 families and of them, more than 860 species under 59 families belong to dicotyledoneae and about 340 species under 19 families belong to monocotyledoneae. In the tropical and subtropical parts of the world, about 90 species of vegetable crops are cultivated, but hardly 20 of them are commercially important.

In the present botanical classification, over 140 different vegetable crops under 6 monocotyledoneae and 20 dicotyledoneae families have been included.

Maize (Zea mays L.) has tropical origin and is traditionally grown in monsoon. The crop is grown in diverse geographical and climate conditions around the world and in India maize is grown in kharif (rainy season), rabi (winter season) and spring seasons where more than 70 per cent of the production happen in kharif alone. Of late, the area under rabi maize has increased because of higher productivity and ever increasing demand.

Insect pests of maize

Compared to most cereals, maize faces fewer biotic and abiotic constraints in production. Among biotic stresses, insect pests are major constraints in the production and productivity of maize crop. The earlier literature cites over 160 insect and mite species which attack maize crop (Fletcher, 1914, 1917; Ayyar, 1940; Bhutani, 1961; Pant and Kalode, 1964) but later Mathur (1987) observed over 250 species of pests associated with maize in field and storage conditions. Dick and Guthrie (1988) identified 87 species that directly or indirectly exert severe stress on corn culture in tropical and temperate regions throughout the world. Excluding stored grain insects, Luckman (1978) lists 34 pests or pest groups for which chemical controls are recommended on corn in the United States. There have been more than 130 insect pests reported to cause damage to maize in India but only about a dozen cause economic losses (Sarup et al., 1987).

Shrinking land resources, vulnerable market of cash crops along with climatic aberrations have adversely affected the Indian agriculture and as a result, small farmers are increasingly alienating from this profession. To sustain their livelihood, farmers are increasingly adopting the alternative sources and dairy farming is one of the best-suited businesses, which can rightly fit at this stage. It is fast emerging as a potential business in rural India, particularly in the peri-urban belt. Among the major inputs required to set up a dairy unit, round the years availability of good quality fodder is the foremost requirement. Green forages are rich and cheapest source of carbohydrates, protein, vitamins and minerals for dairy animals. The importance of forages in our country is well recognized since feeding forages alone accounts for over 70% of the cost of milk production. Hence by providing sufficient quantities of green fodder instead of costly concentrates and feeds to the milch animals, the economics of dairy unit can easily be maintained. Milch animals need around 40 kg of green fodder daily for better milk production and for maintaining good health of the animal. There is a large number of fodder crops grown in our country, the majority being dominated by pearl millet, sorghum, maize and oats in the non-leguminous and berseem and lucerne in the leguminous category. Pearl millet and sorghum are extensively grown as cereals in the southern and dryer regions of the country and the stover remained is used as animal fodder. However, the nutritional quality of the stover is very poor due to higher content of indigestible lignin and low levels of cellulose, whereas, the cultivated green fodders are mostly confined to the North-Western plain zones of Punjab, Haryana and Western Uttar Pradesh. The availability of round the years quality green fodder, therefore, seems to be a tough task. At present, the country faces a net deficit of 61.1% green fodder, 21.9% dry crop residues and 64% feeds (IGFRI Vision, 2030).

Foodgrains are a fine example of diversity of nature with many varieties and varied features. They are storable food commodities and lend themselves to numerous processing manipulations. Nutritionally foodgrains are rich source of almost all known nutrients and several phyto-chemicals. The increasing incidence of metabolic diseases are attributed to unbalanced energy rich diets lacking in fiber and protective bioactive compounds such as micronutrients and phyto-chemicals (Prakash, 2013). Cereals along with pulse combinations constitute an important part of human diet in many parts of the world because of easy availability, low cost, long shelf life and nutritional balance. During recent past, India has made significant progress in improving the food security of its masses. The green revolution of 60’s helped the country in achieving the food security by improving the availability and access components (Kaul et al., 2016). However, surplus quantity of food produced is not uniformly distributed and the quality component is not addressed properly which has a direct impact on nutrition. In spite of surplus production of foodgrains still malnutrition persists. However, it can suitably be overcome by combining cereals with good quality pulses and other value addition techniques which will go long way in solving the problem of malnutrition. Even though country is producing large quantity of coarse grains particularly maize but its utilization for direct consumption is very low which is mainly due to poor quality of protein. Although maize contains higher proportion of protein (10-12 %), its quality is poor as compared to that of protein in rice due to presence of high concentration of alcohol soluble protein fraction ‘prolamine’ also known as ‘Zein’ in the endosperm. Zein is very low in some essential amino acids, mainly lysine and tryptophan which contribute to more than 50% of the total protein. On the other hand, very high amount of leucine and imbalanced proportion of isoleucine contribute to poor quality of protein in normal maize. To overcome such deficiencies, scientists developed Quality Protein Maize (QPM) where the quality of protein is not only higher than the common maize, but also significantly higher than that of other cereal grains. In the recent past QPM has got special distinction among the cereals due to presence of high amount of essential amino acids like lysine and tryptophan. QPM can be utilized for diversified purposes in food and nutritional security as infant food, health food, convenience food, specialty food and emergency ration. In India maize is consumed mainly in the form of boiled corn or roasted as pop corn. In order to increase the proportion of maize for direct consumption, several traditional food-processing and preparation methods can be used at household level to enhance the bioavailability of micronutrients in maize based diets. These methods include alkali cooking, thermal processing, mechanical processing, soaking, germination/ malting and fermentation. In countries like Central America and Africa, it is converted into food products by grinding, alkali processing, boiling, cooking and fermentation (Srilakshmi, 2008).

Maize or corn (Zea mays L.), which was first domesticated in Mexico, is the most widely grown cereal crop in the world. Maize is consumed as feed and food, and also has myriads industrial applications, including the production of bioethanol and starch. Due to its highest genetic potential, production and productivity among the cereal crops, maize is called as “Queen of the Cereals”. Noble Laureate Dr. Norman E. Borlaug, the Father of Green revolution stated 15 years ago that “The past two decades saw the revolution in rice and wheat, the next few decades will be known as maize era”. In India, maize is the third largest grain crop and its production and demand is increasing rapidly. In India, it is primarily a non-food cereal crop, with only 10% being consumed as direct human food, while the rest being used for feed, industrial and export purposes. The effective deployment of various frontier technologies viz. genetic engineering, doubled haploids, molecular markers, phenomics etc.has greatly helped in raising productivity of maize crop worldwide in the last decade.The present chapter provides an overview on role of frontier technologies in maize crop improvement.

Seed in agriculture recognized as one of the most vital and crucial input in agriculture ever since the human kind has started tilling the land to produce the food for his existences. Seed technologist defined seed as matured fertilized ovule consisting of an intact embryo, endosperm and or cotyledon with protective covering (seed coat). A quality hybrid maize seed production system ensures design of the production technology which enables to maintain the healthy embryo, endosperm and /or cotyledon with protective covering. In fact the search of quality seed had acted as a major force to evolve the science of plant breeding. Ever since the farmers understood the importance of seed, they started trading the quality seed within community and now between geographies. Self-pollinated crops possess the natural mechanisms to maintain the intactness of genetic constitution of a seed during multiplication as there is very minimal chance of natural crossings. On the contrary, cross pollinated crops like maize requires special techniques in seed multiplication to maintain the genetic constitution of a F₁ hybrid. Hybrid Maize seed production techniques are well defined and are used by public and private sectors to produce the required hybrid seed in India. In this chapter, I will be highlighting the process, potential agro-climatic zones, hybrid maize seed production capacity and its future perspective in India. In addition, it also reviews the current system and possible strategic move in order to support the maize seed production system and steps required to meet future demand.

Maize is a miracle crop and is popularly known as “Queen of Cereals” due to its very high yield potential. It’s a leading crop worldwide in terms of area, production and productivity and is suitable to diverse agro-climates. Its extent of adaptability is unmatched by any other crop. Due to this adaptability to diverse climates, maize had been grown by many generations in different parts of the world. Earlier, the primary utilisation of maize was focused towards human consumption and even today it is a staple food of many underprivileged societies especially in African countries and certain tribal pockets in India. It is playing an important role as a cheap source of carbohydrate in daily meals due to high productivity and wider adaptability. With the passage of time the productivity increased due to conscious selection towards high yield by farmers and researchers. This enhanced production and productivity opened new doors of utilisation of this wonderful crop. Maize found its place as a feed crop for economically important anima ls like chicken and swine. This shift towards feed industry got encouragement by change in the food habits of people. Looking at the recent consumption pattern of maize as a food crop displays declining trend. As per a NSSO survey (2014) maize consumption in rural areas in India has seen a decline of around 35% from 3.7 kg/year in 2004-05 to 2.4 kg per year in 2009-10, and further declined to 1.56 kg during the year 2011-12. Continued efforts towards yield enhancement and decline in human consumption made its way to utilise surplus maize in economically viable industrial products. Maize is a crop where every part of its plant can be utilised to produce food and non-food products. Oil, starch, glucose, dextrose and sorbitol are few important products produced by processing of maize grains. Apart from these, maize has been very widely used for production of ethanol which is used as a fuel in many developed countries. Direct utilisation of maize grains in poultry and other feed industries is on the rise with increasing demand of such foods. Maize oil is of high quality and is being widely used in developed countries. Maize is a major source of industrial starch which finds its way to diverse utilization such as food and beverage, pharmaceutical, textile, paper and other industries. Processing of maize is done by two ways- Dry Milling and Wet Milling. Wet milling produces starch, gluten and husk and Dry Milling produces corn meal, germ, grits and animal feed. Apart from these processed products, maize is also being developed to be utilised as a biopharmaceutical crop. Maize crop is being bioengineered to extract products of therapeutic and medicinal importance. Such a diverse utilisation of maize has generated a necessity to improve morpho-physiological traits which are important with respect to its industrial utilisation. In the present chapter, we will discuss various aspects of maize improvement for industrially important traits which will include oil, starch, methionine, biofuel and biopharmaceuticals.

The ever mounting population in 21^st century is a great challenge for the researchers to provide ample food and that has to be achieved within the context of existing challenges such as deteriorated arable land along with increasing adverse affects of changing climate. There is demand to increase food production to the tune of 70% by 2050 (Wani and Sah, 2014). Although major crops have achieved good progress, vulneRability to climatic variability emerged as a serious concern in crop improvement which could be attributed to higher sowing densities that in turn lead to more competition for water and nutrients. Abiotic stresses can be considered as major yield restraining factors among different crops. The projected estimations for changes in abiotic stresses such as drought, water logging and heat reveals far serious concerns for crop productivity (Qin et al., 2011; Bailey-Serres et al., 2012). Therefore, the concern of global food security in the era of climate change has compelled plant scientists in different crops to shift to breeding for climate resilient genotypes. Maize, being a hardy crop has an inherent potential to perform well under sub-optimal environments with minimum crop management (Kole et al., 2015). Abiotic stresses such as drought, heat and water logging affects maize yield adversely.

Although, conventional breeding approaches have exploited its fullest potential for production of elite maize hybrids but still little success attained for breeding climate resilient genotypes or varieties owing to the fact that stress tolerance is multi-genic or quantitative in nature. Therefore, the best option is to utilize the molecular breeding along with the conventional approaches for development of climate smart varieties.

Maize occupies an important position in the world economy, and serves as an important source of food and feed (Gupta et al., 2015a). Together with rice and wheat, it provides at least 30% of the food calories to more than 4.5 billion people in 94 developing countries (Shiferaw et al., 2011). In India, maize is an important cereal too, and is grown on an area of 9.2 million hectares with production of 24.2 million tonnes (www.indiastat.com). The demand for cereals will continue to increase as a consequence of the expanding human population. The world will have around 7.7 billion people by 2020, and it will reach up to 9.3 billion by 2050, and the demand for maize between now and 2050 will double in the developing world (Rosegrant et al., 2009). By 2025, India too would require to double the production (50 million tonnes) of maize grain to meet the domestic demand (Yadav et al., 2016).

Malnutrition caused by inadequate consumption of balanced diet has emerged as one of the alarming problems especially in the under-developed and developing world. Mostly the resource-poor suffer from ‘hidden hunger’, a term often used to describe malnutrition caused due to micronutrient deficiencies in staple food diet (Bouis and Welch, 2010).

An estimated two billion people suffer from micronutrient deficiency, while 795 million people are undernourished (IFPRI, 2016a). Of the 667 million children under the age of five worldwide, 159 million are stunted, while 50 million do not weigh enough for their height (IFPRI, 2016b). An estimated 45% of deaths of children under age five are linked to malnutrition (Black et al., 2013). Malnutrition contributes to global burden of disease, and loss in annual gross domestic product (GDP) in Asia and Africa to extent of 11%. South Asia is home to more than 35% of the world’s poor, and 21.9% of the population of India lives in poverty, and thus vulnerable to various health problems (IFPRI, 2016a). 15.2% of the people in India are undernourished, and more than one third of the world’s underweight malnourished children live in India, posing severe socio-economic loss to the country.

The ability to fast-track development and delivery of improved maize cultivars with capacity to provide climate-resilience (high and stable yields in stress-prone environments), coupled with improved nutritional quality, will be critical for sustainable intensification and diversification of maize-based cropping systems, and for providing enhanced income opportunities to the smallholders. This warrants coordinated multi-institutional efforts and implementation of innovative strategies to further increase genetic gains through breeding, and to translate these gains in the farmers’ fields. This article will focus only on the novel tools/ technologies/strategies that are being employed by CIMMYT for increasing genetic gains, especially for grain yield under stress-prone environments in the tropical/sub-tropical regions of sub-Saharan Africa, Latin America and Asia.

Novel tools/techniques/strategies for increasing genetic gains in the tropics

“Genetic gain” (also called as selection response) refers to the difference in the mean value of the selection criterion between original generation and next generation (formed from only the selected individuals), when they were compared in the same environment. The selection criterion is the trait(s) on which selection is based. While conventional breeding has been successful in improving maize yields over the decades, and especially in the last one decade in India through single-cross hybrids, the significantly rising demand for maize in the tropical regions of sub-Saharan Africa and Asia warrants sharp increases in genetic gains. Thus, the major challenge for the present generation of product development teams is to double the genetic gains for grain yield under stressed environments, i.e., from the present <1% to at least 1.5% within the next 5-6 years.

Maize (Zea mays L.) occupies an important place in world agriculture due to its high yield potential and greater demand. Because of its divergent character, maize is grown over a wide range of climatic conditions, ranging from near sea-level to several thousand meters above sea-level (2,700 msl). It can also be grown in all types of soils ranging from sandy to heavy clay. Among the factors adversely affecting productivity, incidence of diseases is prominent. In India Maize is prone to a number of biotic stresses like foliar diseases, downy mildews, banded leaf and sheath blight, stalk rots and ear rot caused by fungi and bacteria, incidence of which are variable in time, space, and genotype. Disease may be minimized by the reduction of the pathogen’s inoculum, inhibition of its virulence mechanisms, and promotion of genetic diversity in the crop (Richard et al., 2005). Conventional plant breeding for resistance has an important role to play that can now be facilitated by marker-assisted selection.

Chemical control measures for some of the diseases are helpful in reducing losses, however for stabilizing production it is necessary to build level of genetic resistance. Germplasm improvement programme undertaken in sixties and early seventies by All India Co-ordinated Maize Improvement Project provided an opportunity for combining resistance against important diseases with other desirable agronomic traits. Thus, breeding for resistance had been an important objective of the overall crop improvement programme and it had been a cooperative venture of the plant breeders and plant pathologists. Consequently, it was recognized that there should be an efficient technique for the mass multiplication of inoculums, artificial inoculation technique and scoring/rating of plant disease as a pre-requisite for the successful identification of resistant sources in such improvement programme. With these objectives in to consideration, a six days seminar on the “Techniques of scoring for resistance to diseases of maize in India” was held at Andhra Pradesh Agriculture University, Hyderabad during 15-20 March, 1982 (Payak and Sharma, 1983).

Maize (Zea mays L., 2n=20) is a cereal crop that is grown widely in more than 165 countries in a range of agro-ecological environments. Even in Asia, the rapid increase in maize acreage in the last decade is an indication that it is winning the battle as compared with rice. The Asian region will see itself as a major global player in the near term. In the past it was mainly confined to food in India and many other countries however, now it has become the industrial crop. Maize has several industrial applications and more than 1000 products are being developed from maize in India and around 3500 products in USA and other countries. It is a raw material for many of the important industries viz. pharma, textile, paper, film, tyre food, processing, packing and biofuel, etc. The growth rate of poultry, livestock, fish, wet and dry milling industries are very high therefore, maize demand will continue to increase in year to come.

Global Maize Scenario

Globally, maize is primarily used as feed livestock and has many industrial uses; however in many developing countries it is still used as a food crop. Small-scale farmers in both sub-Saharan Africa and Mesoamerica generally grow maize as a food crop for household consumption and for saline urban markets. Maize is particularly important in the diets of the rural and urban poor in sub-Saharan Africa and Latin America. Globally, maize is grown in 165 countries in a total of 185.1 million hectares area with 1018.1 million tones of production and 5.52 tonnes/ha productivity (Anonymous 2015-16). Almost 70% of the total maize production in the developing world is coming from low and lower middle income countries. In Asia, maize has recorded the fastest annual growth (around 4%), as compared to other cereals. Maximum maize production was in USA (353.7 million tonnes) followed by China (218.6 million tonnes) and Brazil (80.3 million tonnes) (Fig. 1), while the area under maize cultivation was in China (36.3 million hectare) followed by USA (35.5 million hectare) and Brazil (15.3 million hectare) (Fig. 2). The average world maize productivity is 5500 kg/ha, but the highest productivity of maize was achieved in USA (9970 kg/ha) followed by Canada (9591 kg/ha) and France (8137 kg/ha) (Fig. 3).

Maize (Zea mays L.), the “Queen of Cereals” is one of the most important highly evolved coarse cereal crop originated at Mexico. This is most widely distributed crop of the world cultivated predominantly in tropics and sub-tropics right from sea level to 4000 m altitude as irrigated or rainfed crop. The demand for maize as an animal feed will continue to grow faster than the demand for its use as a human food, particularly in Asia, where, doubling of production is expected from the present level of 165 m t to almost 400 mt.

Maize (Zea mays L.) is the third most important crop of country after rice and wheat and is cultivated round the year. Its grain is used as feed, food and industrial raw material. Enormous progress has been made during last six decades to enhance yield potential through genetic improvement and alleviate effects due to various biotic and abiotic-stresses. In India, it is an important crop not only in terms of acreage but also in context to its versatility for adoption under wide range of agro-climatic conditions. Of the different forms used for human consumption, 45% is consumed as staple food in various forms viz., bread, biscuits, cookies or transformed into corn flakes, soups, fresh-roasted sweets, boiled cobs and vegetables etc. Maize grain is main ration for poultry birds while forage maize is used as fresh or dry fodder for dairy industries. In Rajasthan maize occupies 0.89 m ha area with an annual production of 1.55 mt and productivity of 1.74 t/ha (Govt of Rajasthan, 2015). Being major Kharif crop in Rajasthan, the productivity levels of maize are still below the national average and farmers are not getting better economic returns. However, profitability can be accelerated further by growing recently popular speciality corns.

Maize ranks fourth after rice, wheat and bajara with respect to area and production, and grown on 4.23 lakh ha average with 6.72 lakh tones production and yield 1589 kg/ha in the Gujarat (2014-15). The state has 38.0% lower than national yield. It mainly grown in Panchmahal, Dahod, Mahisagar, Vadodara, Chhota Udepur, Kheda, Sabarkantha, Banaskantha and Aravali districts as rainfed Kharif and irrigated winter/Rabi crop for food, feed and industrial raw materials.

It is staple food and feed of tribal and grown as sole and intercrops with pigeon pea, black gram and soybean in Kharif season. The white and yellow flints to semi-flint maize are preferred to prepare bread and other food preparations

The state of Madhya Pradesh is one of the high profile maize growing state of the country cultivating maize in about 11.32 lakh hectare area which is ~12% of the total maize area of the country having 90-95% of total maize area having rainfed. Madhya Pradesh is situated in heart of India between 17°-26° N latitudes and 74°-84° E Longitude. The rainfall in maize growing belt varies from 800 to 1600 mm. Due to erratic and uneven rainfall in the state, the production and productivity of maize fluctuates every year. Maize cultivation in the area is associated with resource poor tribal farmers. As the demand for maize is growing globally due to its multiple uses for food, feed and industrial uses, we need to produce more from same or even less resources, which can be achieved through targeting technologies in potential regions.

Besides, monsoon crop due to mild winter conditions the climate allows the cultivation of maize during winter successfully under assured irrigation conditions. At present about 50 thousand ha area is under Rabi cultivation with high productivity levels as compared to monsoon crop. However, the major area increase was achieved during past few years mainly due to adoption of hybrids and shift in acreage under non-traditional areas, replacing soybean crop on farmers field. Uncertain climatic conditions and more disease and pest problem lead farmers to adopt maize in place of soybean.

The trends in area production and productivity of maize in Madhya Pradesh has shown a remarkable increase during four decades. During 1966-67 the maize acreage in the state was very less (5.59 lakh ha) that has grown up by 11.32 lakh ha in 2014-15. Moreover, the productivity also increased dramatically from mere 811 kg/ha during 1966-67 to 1513kg/ha in 2014-15.

Maize (Zea mays L.) is the third most important grain crop in India after rice and wheat with respect to area and production. It has wide ecological adaptability and is grown in almost all parts of the country extending from extreme semi-arid to sub-humid and humid regions. The crop is also popular in low and mid-hill areas of Western and North Eastern regions. It has the highest yield potential and used as human food, animal feed and as a source of large number of industrial by-products. Hence, it is called as “Queen of cereals”. In India, about 59% of the total production is used as feed, while the remaining is used as industrial raw material (17%), food (10%), exports (10%), and other purposes (4%).

Tamil Nadu has a total geographical area of 13 million hectares with a coastal line of 922 km and is endowed with 3 per cent of water resources of the country. Out of 13 million hectares of geographical area, the cultivable area in Tamil Nadu is around 7 million hectares and 55 per cent of which is dryland. The State has gross irrigated area of 33.94 lakh ha out of which 79% is under food crops and 21% is under non-food crops. In Tamil Nadu, maize was grown in an area of 0.14 lakh ha during 1970-71 with the annual production of 0.16 lakh tonnes, mainly concentrated in Tanjore, Pudukkottai and Trichy districts. Due to rapid increase in the demand of maize for poultry and animal feed, industrial uses and introduction of high yielding varieties and hybrids, the area under maize has gone up to 3.8 lakh ha with the production of 22.45 lakh tonnes during 2013-14. The major maize growing districts are Perambalur, Tuticorin, Dindigul, Erode, Karur, Ariyalur, Salem and Southern districts of Tamil Nadu. The demand and production of maize is increasing more rapidly as compared to other major commodities. It is estimated that the demand for maize will continue to increase in coming days (Yadav et al., 2016). Thus, in the next 10 years there is a necessity and opportunity for doubling India’s maize production from the current level of approximately 26 million MT.

Maize production in India has been dominated by erstwhile Andhra Pradesh and Karnataka which together contribute around 38 per cent of the total maize production of the country. Erstwhile Andhra Pradesh has achieved the highest mean yield of 4441 kg/ha in the country during the last decade (2001-02 to 2010-11) by surpassing Karnataka which had the highest productivity in the country, earlier. The main reason for achieving the highest productivity in the country was due to adoption of improved production technology along with 100% area grown under hybrids. In Telangana, maize is the third most important crop after rice and cotton. It is cultivated in 5.74 lakh hectares, predominantly in Kharif season (4.54 lakh ha), with a productivity of 3.69 t/ha (2015-16).

Trends in maize area, production and productivity in the state (1950 to 2016)

The erstwhile Andhra Pradesh (including Telangana) is the non-traditional maize growing state. But, the climate of the state is very favorable for the crop and hence maize can be grown in any season in the state. However, it is mainly grown as a rainfed crop during monsoon season, concentrated in Telangana. The trends in area, production and productivity of maize in erstwhile Andhra Pradesh have shown a remarkable increase during the past six decades. During 1955-56, the maize acreage in the state was very less (1.89 lakh ha), which has been up by 5.3 times to the present (2014-15) level of 9.95 lakh hectares. The production has also increased dramatically from merely 1.14 lakh tonnes during 1955-56 to 42.36 lakh tones during 2014-15, which is nearly 37 times higher. Similarly, the productivity of maize in the state was merely 601 kg/ha during 1955-56, which has been increased to 4257 kg/ha during 2014-15 (Fig. 1).

Karnataka is India’s eighth largest state in geographical area covering 1.92 lakh sq km and accounting for 6.3% of the geographical area of the country. As per the population Census 2011, agriculture supports 13.74 million workers, of which 23.61 per cent are cultivators and 25.67% agricultural workers. A total of 123,100 km² of land is cultivated in Karnataka constituting 64.6% of the total geographical area of the state (Table 1). Of the total cultivated area in the state, about 33.0% is covered by cereals, 42% by pulses and 19% by oilseeds and 6.0% by commercial crops (Savitha and Kunnal, 2015). Agriculture employs more than 60% of Karnataka’s workforce. The large portion of agricultural land in the state is exposed to the vagaries of monsoon with severe agro-climatic and resource constraints.

Maharashtra is the third largest state in terms of area in the country located in the north-centre of peninsular India. It links the southern part of the northern plains to the southern peninsula. Maharashtra occupies the western and central part of the country with total 3.08 lakh sq. km geographical area and has a long coastline stretching nearly 720 kilometers along the ARabian Sea. The prominent physical trait of the state is its Plateau character, which has up to 1350 meters high altitude. Physiographically this state may be divided into three natural divisions-the coastal strip (the Konkan), the Sahyadri or the Western Ghats and the Plateau. The Sahyadri mountain ranges provide a physical backbone to the state on the west, while the Satpuda hills along the north and Bhamragad-Chiroli-Gaikhuri ranges on the east serve as its natural borders. It has a geographical area of 307713 sq. km and is bounded by north latitude 15°40’ and 22°00’ and east longitudes 72°30’ and 80°30’.

NBSS & LUP has divided the state into 356 soil mapping units and published a map of the soils of Maharashtra. It has broadly categorized as soils of Konkan coast, soils of Western Ghats, soils of upper Maharashtra, soils of lower Maharashtra. The soil status of Maharashtra is residual, derived from the underlying basalts. In the semi-dry Plateau, the regur (black-cotton soil) is clayey, rich in iron and moisture-retentive, though poor in nitrogen and organic matter. The rainy Konkan and the Sahyadri Range, the same basalts give rise to the brick-red laterites, which are productive under a forest cover, but readily stripped into a sterile varkas when devoid of vegetative cover. The soil in the Deccan Plateau is made up of black basalt soil. This type of soil is rich in humus. The soil is commonly known as the black cotton soil because it is best suited for the cultivation of cotton. The volcanic action which had taken place in the Deccan region has given rise to the soil texture and composition. These igneous rocks break down into the black soil which is very fertile. The Wardha-Waliganga river valley has old crystalline rocks and saline soils which make the soil infertile. This type of soil has a natural resistance to wind and water erosion because it is rich in iron and granular in structure. A very important advantage of this type of soil is that it can retain moisture. This makes the soil very reactive to irrigation.

Maize is presently the crop with growing importance in the state. Earlier it was primarily grown for human consumption only. In view of rapidly increasing demand of poultry feeds and fodder in Assam presently it has more use in some small industries. It is the raw material for most of the feed industries. Presently the crop has state acreage of 27953 hectare and production of 93179 tonnes with a productivity of 3333 kg/ha (2014-15).

While most other states in India are gradually moving away from their traditional agriculture based economy toward industry or service oriented economy, Assam is still predominantely dependent on the agricultural sector. While the sociopolitical problems afflicting the state since the last few decades are partly to blame for a lack of conducive environment for economic development of the state, particularly in industry or service oriented areas, there are various economic reasons (e.g. fragmented land) responsible for the lagging agricultural sector in the state. Economy of Assam is fundamentally based on agriculture. Over 70% of the state’s population relies on agriculture as farmers, agricultural laborers, or both for their livelihood.

Assam produces both food and cash crops. The principal food crops produced in the state are rice (paddy), maize (corn), pulses, potato, wheat, etc., while the principal cash crops are tea, jute, oilseeds, sugarcane, cotton, and tobacco. Although rice is the most important and staple crop of Assam, its productivity over the years has not increased while other crops have seen a slight rise in both productivity and acreage.

Maize is the only cereal crop which is being used as human food, animal feed and as a source of large number of industrial products. In Odisha traditionally maize is a Kharif season crop and second most important crop next to paddy during Kharif season in terms of both area and production. The Rabi maize is cultivated under irrigated condition, and accounts only 7% of total area and production of the State. While only 24% of the Kharif maize area have irrigation facilities. Irrespective of the season, it is that is the fourth most important food grain crop with respect to area in the state which is next to rice, mungbean and urdbean. Even though maize is grown as a sole crop in the state but, some farmers are also adopting maize based inter-cropping and the major recommended/adopted inter-crops are arhar, cowpea, yam, runner bean, greengram and blackgram. The comparative analysis of compound annual growth rate (CAGR) of area, production and yield of the major crops is the state was done for the years 2004-05 to 2013-14. The CAGR study of major crops revealed that no other major crop including rice has the impressive growth rate a like maize in the state (Fig. 1).