Most farmers in Asia and Africa depend on the rains to grow their crops. However, rainfall is not uniform. In 2006, 112 of the 533 meteorological districts in India, received excess rain, while the situation was normal in 193 districts. Also, India has vast stretches of land that are drought-prone, so the legumes grown here have very low productivity. Crop breeders have been working tirelessly to develop drought tolerant varieties for decades with some success. However, it takes a long time to breed such varieties with conventional breeding. Recent advances in crop biotechnology, in the form of genomics and genetic engineering, can provide speedier results.
We need groundnut varieties that can overcome
the harsh conditions of the semi-arid tropics. The use of genomics in breeding is internationally accepted. For many temperate cereal crops, genomics approaches have facilitated the development of superior varieties. However, this has not been the case for legume crops due to the non-availability of appropriate tools (molecular markers, genetic maps in semi arid tropic legumes like groundnut). Once these genomic tools are available and genes are identified for drought tolerance, they can greatly facilitate the breeding for this trait. Such varieties, developed eventually by a combination of conventional and molecular breeding, can produce seeds that can be grown even in drought-prone areas, which should produce higher yields.
Together with colleagues from the Catholic University of Brazil, the Brazilian Agricultural Research Corporation (EMBRAPA), the University of Georgia and Tuskegee University of USA, the genomics team at ICRISAT is actively engaged in developing genomic tools for groundnut. Research carried out by an interdisciplinary team of scientists over the last three years has resulted in developing the first genetic map for cultivated groundnut. This is an important step toward identifying genes that will help in conferring tolerance/resistance to drought and other diseases.
While analyzing this genetic map together with physiological data on the mapping population, a few genomic regions (called QTLs) associated with components of drought tolerance have been identified. However, right now these QTLs are not the candidates for use in breeding programs. But this is the first step towards molecular breeding for drought tolerance in groundnut. Molecular markers and the genetic map developed by ICRISAT scientists are being shared and used by NARS partners such as National Research Centre for Groundnut, Junagadh and University of Agricultural Sciences, Dharwad in India and EMBRAPA in Brazil. Part of these results have been published in Open Access journal (BMC Plant Biology 2008, 8:72) and some results are under communication to other journals.
The Generation Challenge Program of the CGIAR and the National Fund of Indian Council of Agricultural Research (Government of India) are the main sponsors of the research being undertaken on groundnut by ICRISAT's genomics team.
For more information contact: r.k.varshney@cgiar.org