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Lentil( Medikus) is the oldest pulse crop with remains found alongside human habitation up to 13,000 years BC. Its domestication is equally old and was probably one of the earliest crops domesticated in the Old World. It is mainly grown in India, Bangladesh, Pakistan, Egypt, Greece, Italy, countries in the Mediterranean region and North America. It is also being cultivated in the Atlantic coast of Spain and Morocco. The crop has a high significance in cereal-based systems because of its nitrogen fixing ability, its high protein seeds for human diet and its straw for animal feed. It is widely used in a range of dishes and reputed to have many uses in traditional medicine. There are a range of wild lentils but is believed to be the progenitor of the cultivated lentil

The genus includes the cultivated . culinaris, and wild subspecies orientalis - the progenitor, , and , are in the primary genepool, while . ervoides, . nigricans and . lamottei are in the secondary – tertiary gene pool. The Middle East is the primary centre of diversity for the primary genepool, with distribution of . orientalis extending to central Asia, and of extending along the Mediterranean to Spain. The largest collection is held at ICARDA. reserves of diversity are in Turkey and Syria. Documentation and storage of germplasm is discussed.An evaluation database covering a number of genebanks has been developed for lentil germplasm. Core collections are discussed in the context of the generation Challenge program. Application of DNA characterisation is outlined, along with the potential forallele mining for variation in key traits, the study of relationships within and the use of mapping populations. Reference is made to the International treaty for Plant Genetic Resources for Food and Agriculture

Worldwide, the major abiotic restrictions on yield of lentil are drought (usually linked with high temperature) and low temperature. LENMOD, a lentil crop growth model, gives greater understanding of how different climatic factors, including water availability and temperature, interact to determine lentil crop growth and yield. This model has considerable potential in predicting where lentil may be grown successfully. Breeding programmes are underway with the objectives of increasing adaptation of lentil to stress environments. The strategy used to combat drought has been to match the crop’s development with the period of soil moisture availability. Genotypes with early seedling establishment, early and rapid biomass development and early flowering and maturity have been selected in sites of extremely low rainfall. Also, seed has been sown earlier in the spring or in the autumn. Success in the production of cold tolerant cultivars has been achieved by field screening of lentils in areas prone to extreme cold. High yielding varieties have been released for use in sites which experience over winter temperatures of -12 to -30° C

Lentils are one the earliest known crops to be cultivated and archaeological evidence goes back at least 7000 years. They have been in constant use in different societies since then and their consumption has been widespread in developed and developing countries alike. It is consumed for its flavour, its versatility and its high nutritive value and other health benefits which are briefly discussed here and elsewhere in this book. In most of the Asian countries and particularly in the Indian subcontinent the major use for lentil is for making for which the red lentils are preferred. The types of lentil soups prepared in different countries and regions throughout the world vary enormously depending on local tradition and palate from the spicy Indian to the more aromatic north African lentil soups to the meat based European dishes and several recipes are included here. alone describes a whole group of dishes which vary enormously from the different regions of India and the other countries of the subcontinent. They are also used uncooked; either soaked crushed and moulded to make cakes or sprouted as an ingredient in salads in some parts of India and as such provide better nutrient value

The importance of lentils as important dietary sources of macro and micronutrients essential for human welfare has been recognized since ancient times. Lentils provide sufficient amounts of most essential amino acids to meet the nutrient requirements, although they are deficient in sulfur-containing amino acids like most legumes. Lentils also contain fair amounts of other essential nutrients like minerals, vitamins and complex carbohydrates. In contrast, lentils exhibit a considerable amount of non-nutritional compounds like trypsin inhibitors, tannins or phytic acid that are able to interfere with the availability of several nutrients. Different processing conditions that range from the traditional soaking/cooking to germination, fermentation, or several thermal treatments, are usually employed to improve the organoleptic properties of lentil seed and its nutritional value through reducing the negative effect of the above mentioned non-nutritional components. In addition, technological treatments may significantly enhance the functional and beneficial health properties of the processed lentil food products, making consumption of this legume an appealing alternative for today’s world

Lentils are a major international pulse crop (4 million Ha harvested in 2005). However, they fall well behind the major cereal and oilseed crops in planted area as well as behind the other pulse crops of peas, chickpeas and beans. Yields tend to be low (global mean of approximately 0.8 t/ha over the last 16 years) with 95% of the crop raingrown. There are three major areas of production N America, the Indian sub continent and Turkey. There are other areas of production in Australia, Iran, Syria and China. Between them these areas account for over 90% of global production. There are two major groups red (70–80%) and green lentils with Canada being the largest global producer of green lentils. Lentil production in the developing world is relatively static while the population in South Asia, where most lentils are consumed, has been rapidly increasing. This has left countries such as India with a very low supply per head of population. This deficit has to be made up by increases in world trade. The major world player in lentil exports is Canada which in 2005 exported 576,000 t. Other major exporters in the same year were Turkey (118,000 t), Australia (108,000 t) the United States of America (160,000 t). Most importing countries import relatively small quantities from a number of countries. In 2004 the largest lentil importers were Bangladesh (110,000 t), Sri Lanka (93,000 t), Egypt (89,000 t) and Colombia (63,000 t). A recent nine month ban by India on lentil exports has lead to a sharp increase in their price on the world market. In the past some countries, such as Turkey, imported lentils from Canada, processed them, and then re-exported them

Lentil is a protein-rich winter season pulse crop. Its cultivation is concentrated mostly in semi-arid regions in the Indian sub-continent and dry areas of Middle East. It can be grown under conserved moisture conditions after monsoon rains. The sowing of lentil is popular as mono and sequential cropping, intercropping, mixed cropping, relay cropping and multistorey cropping in various countries. In India, Pakistan, Bangladesh and Nepal, rice-lentil system is more common but its cultivation is also done after maize, cotton, sorghum and pearlmillet. It can be intercropped successfully in wheat, barley, mustard and linseed. For mixed/intercropping optimum seeding and planting configuration is very important to achieve higher total productivity. In various experiments lentil+wheat (30%), lentil + mustard 5 : 1 row ratio and lentil+linseed 5 : 1 row ratio showed highest land equivalent ratio than sole lentil. In autumn sugarcane, lentil intercropping revealed higher cane equivalent yield than sole sugarcane. In eastern India, the broadcasting of lentil seed in standing rice about 15 days before the harvest gave significantly higher grain yield than lentil sown after the harvest of rice. The inclusion of lentil in various cropping systems improves physical properties of soil and increases the yield of succeeding cereal crop due to biological nitrogen fixation and other rotational effects. Proper agronomic management, use of bio-fertilizers and mechanical cultivation may not only improvebreak productivity but also help to bring large area under lentil in various cropping systems

Through fixing their own nitrogen, growing lentils offers a substantial saving in the need to use fossil fuels to generate fixed nitrogen for agricultural production. Much of the nitrogen fixed by the lentil crop may then be available for subsequent crops in the rotation as crop residues break down. Estimates for the contribution of N to soils by lentils are generally in the order of 20 kg N ha−1yr−1. However, the level of N fixed by lentils varies considerably, spatially and temporally in response to a host of environmental and ecological factors. Lentils require effective infection by in order to fix nitrogen. This infection process could fail due to a number of reasons including a lack of or inappropriate strains of rhizobia, failure of the plant to invest in the symbiosis, or through altered metabolism. While conditionsthat suit better growth of the lentil crop will normally enhance the nitrogen fixation of the crop there may also be specific situations in which the fixation process is more sensitive and fixation limits the growth of the crop

Lentils are often grown in difficult edaphic conditions on stored soil water. This usually results in low yields. While water stress is often responsible for these low yields, low levels of soil fertility can also be a contributing factor. Lentils can usually fix enough N for their own requirements, although if sown into soil with extremely low available N or into cold, wet soil they may require a small amount of starter N to ensure adequate early growth to support nodulation and N fixation. While responses to fertilisers are variable, there are many reports that P at 40–60 kg/ha can help provide increased yields. Also, application of K at around 20 kg/ha may be beneficial in sandy or eroded soils. Sulfur is unlikely to be deficient if fertilisers containing S impurities are applied to other crops in the rotation. Of the micronutrients Zn and B are the two most likely to be deficient.While breeding and management can reduce the effects of drought stress lentils will often respond to irrigation with substantial yield increases. However, their high sensitivity to water logging means that irrigation can be overdone and thus decrease yield. Irrigation requirements are best calculated by considering the limiting water use deficit of the crop and irrigating to control soil moisture deficit to a value suited to the variety and soil type

Lentils compete poorly with weeds and yield reductions in excess of 80% due to hcompetition have been recorded. In lentil, due to poor early vigour and short height it is critical to minimise weed populations throughout the whole lifecycle. To manage weeds a range of cultural, physical and chemical practices can been employed, both ‘in crop’ and throughout the farming system. Cultural practices include land preparation, seed preparation, sowing and crop establishment method, nutritional management, management of insects and disease and irrigation scheduling. While physical removal or killing of weeds generally occurs either manually or with the tools designed for inter-culturing. These methods integrated with chemicals applied pre-sowing, post-sowing pre emergence and post emergence, provide a sustainable and profitable long term strategy to minimise weeds and maximise grain yield, particularly when implemented with crop rotations throughout the farming system. This chapter provides an overview and discusses principles behind these strategies in lentils across different production regions