Advances in Food Legumes Research at ICRISAT

The mandate grain legumes of ICRISAT include chickpea, pigeonpea and groundnut which are important crops of Asia and Africa. The grain legumes improvement program of ICRISAT has access to the largest collection of germplasm of these crops (20,602 accessions of chickpea, 13,771 accessions of pigeonpea, and 15,446 accessions of groundnut) available in ICRISAT genebank, state-of-the art genomics lab, Platform for Translational Research on Transgenic Crops (PTTC), precision phenotyping facilities for abiotic and biotic stresses, controlled environment facilities and a global network of research partners. The major objectives of grain legumes improvement include high yield, early maturity, resistance/tolerance to key abiotic and biotic stresses, and market preferred grain traits (size, shape and color). The crop-specific breeding objectives include suitability to machine harvesting and herbicide tolerance in chickpea, development of hybrids in pigeonpea, and enhanced oil yield and quality (high oleic content) and tolerance to aflatoxin contamination in groundnut. The crop breeding programs have been making extensive use of the germplasm, including wild species. The advances in genomics include availability of draft genome sequences, large number of molecular markers, high density genetic maps, transcriptomic resources, physical maps and molecular markers linked to genes/quantitative trait loci for key traits. There are successful examples of introgression of traits through marker-assisted backcrossing in chickpea and groundnut. Transgenics events are available for pod borer resistance in chickpea and pigeonpea and drought tolerance in groundnut. Advances have also been made in use of secondary metabolites for promotion of plant growth, control of insect pests and plant pathogens, and biofortification. The breeding materials and germplasm supplied by ICRISAT have led to release of 160 varieties of chickpea in 26 countries, 91 varieties/hybrids of pigeonpea in 19 countries and 190 varieties of groundnut in 38 countries. Many of these varieties have been adopted widely by farmers and benefitted them in sustainably improving their livilihoods

Genetic Enhancement Perspectives and Prospects for Grain Nutrients Density

Diet-induced micronutrient malnutrition continues to be a major challenge globally, especially in the developing world. With the ever-increasing population, it becomes a daunting task to feed millions of mouths with nutritious food. It is time to reorient agricultural systems to produce quality food to supply the calorie and nutrient requirements needed by the human body. Biofortification is the process of improving micronutrients density by genetic means. It is cheaper and sustainable and complements well with the nutrient supplementation and fortification— the short-term strategies that are currently deployed to address the micronutrient malnutrition. Sorghum is one of the important food crops globally, adapted to semi-arid tropics, and there is increased awareness on its nutritional importance. Further, there is great opportunity to improve sorghum for nutritional quality. This chapter deals about the genetic enhancement perspectives and prospects for improving the nutritional quality with main emphasis on grain micronutrient density in sorghum

Integrated striga management (ISM) in East Africa

The parasitic weed Striga (Striga spp.) is an important constraint to crop production in Africa. Crop losses due to Striga have been severe and significant. Past research into the control of Striga has resulted in promising technologies including adapted Striga resistant crop cultivars, improved tillage and cultural practices, as well as the potential use of chemical inputs. Each of these control measures may provide significant relief to subsistence farmers confronted by severe Striga infestation. However, a more enhanced control of Striga can be achieved by combining two or more of these individual approaches synergistically. Yet, there have been limited research undertaken to evaluate the benefits of integrating multiple control options against Striga. Recently, we have established on–farm experiments in Eastern Africa to demonstrate the impact of integrated Striga management (ISM) using Striga resistant sorghum cultivars, nitrogen fertilizers, and tied-ridges as a water conservation measure. This Pilot Project started in Ethiopia and has now been extended to Eritrea and Tanzania. The program is focused on increasing the agronomic benefit of the ISM package, in promoting a functional seed production program through farmer organizations, and to enhancing the profitability of farmer’s investments in the ISM technology. In Ethiopia during the last two crop seasons, nearly 3000 one-half hectare demonstration plots have been planted to the ISM package with excellent results. Collaborators from national and regional research programs, regional Bureaus of Agriculture, and farm organizations were actively involved. Training was provided to participants promoting better understanding of Striga biology, control measures, and improved crop management practices including ISM Data collected over the two years showed drastic reduction in Striga infestation and often a ten-fold increase in sorghum yield when the ISM technology was applied. In the most severe cases, only the Striga resistant sorghum cultivar combined with improved agronomic practice gave measurable grain yield while local practices applied on to susceptible landraces often resulted in total crop failure. Encouraged by the results of these experiences, the government of Ethiopia recently proclaimed the nation-wide use of ISM in all Striga endemic areas of the country. Of 195 farmers who have taken up seed production through the pilot project, 31% successfully produced seed which met the quality standards and was sold back to the Pilot Project and to NGOs for wide distribution. A more organized and sponsored effort is needed to promote sustainability of the program nationally and to enhance profitability of the ISM package to participating farmers.

Genetic erosion and changes in distribution of sorghum (Sorghum bicolor L.(Moench)) landraces in north-eastern Ethiopia

Ethiopia is believed to be the centre of origin and domestication for sorghum, where sorghum remains one of the main staple crops. Loss of biodiversity is occurring at an alarming rate in Ethiopia and crops, including sorghum, have long been recognized as vulnerable to genetic erosion. A major collection of sorghum germplasm was made in 1973 by Gebrekidan and Ejeta from north-eastern Ethiopia. A new collection of landraces was made in 2003, and these were field evaluated at Sirinka in 2004 along with representative samples from the 1973 collection. Farmer surveys and soil and climate surveys were also performed. Preliminary analysis demonstrated that some important landraces have disappeared either locally or regionally in the past 30 years and many other landraces have become marginalized. Landraces which are less preferred in terms of agronomic value and end use, and introductions, have become increasingly important. Late maturing landraces were found to be particularly vulnerable, with a number disappearing altogether. Farmers have become more risk averse, and factors such as declining soil fertility, more frequent drought and unreliable rainfall, and increased pest infestation have contributed to a change in farmer landrace selection. Data are presented on the variability and unique characters of some of the Ethiopian landraces, and implications for conservation are discussed © NIAB 200

Genetic structures of the CIMMYT international yield trial targeted to irrigation environments

International yield trials are assembled by CIMMYT to disseminate promising wheat breeding materials worldwide. To assess the genomic structure and linkage disequilibrium (LD) within this germplasm, wheat lines disseminated during 25 years of the Elite Spring Wheat Yield Trial (ESWYT) targeted for irrigated environments of the world were genotyped with the high-throughput Diversity Arrays Technology (DArT) marker system. Analyses of population structure assigned the ESWYT germplasm into five major sub-populations that are shaped by prominent CIMMYT wheat lines and their descendants. Based on genetic distance, we concluded that a constant level of genetic diversity was maintained over the years of ESWYT dissemination. Genetic distance between the individual ESWYT lines significantly increased when the ESWYT were grouped according to the differences in years of ESWYT dissemination, suggesting a systematic change in allele frequencies over time,most probably due to breeding and directional selection. By means of multiple regression analyses, 78 markers displaying a significant change in allele frequency across years were identified and interpreted as an indicator for constant selection. The markers identified were partly associated with grain yield, leaf, stem, and yellow rust and point to key genomic regions for further investigation. Large numbers of adjacent DArT marker pairs showed significant LD across the ESWYT population and within each of the five subpopulations identified. Sub-population differentiation measured by the fixation index and average genetic distance were highly correlated with LD levels, suggesting that the sub-populations themselves explain much of the LD