Location: Crop Protection and Management ResearchTitle: Advances in Arachis genomics for peanut improvement Author
Submitted to: Biotechnology Advances
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/1/2011
Publication Date: 5/25/2012
Citation: Pandey, M.K., Monyo, E., Ozias-Akins, P., Liang, X., Guimaraes, P., Nigam, S.N., Upadhyaya, H.D., Janila, P., Zhang, X., Guo, B., Cook, D.R., Bertioli, D.J., Michelmore, R., Varshney, R.K. 2012. Advances in Arachis genomics for peanut improvement. Biotechnology Advances. 30:639-651. Interpretive Summary: Peanut or groundnut is the fourth largest oilseed crop in the world and is cultivated in more than 100 countries with the annual production of 35.5 million tones. Peanut seeds contain 40-60% oil, 20-40% protein and 10-20% carbohydrate. Peanut has high nutritional value possessing vitamin E, niacin, folic acid, calcium, phosphorus, magnesium, zinc, iron, riboflavin, thiamine and potassium. The cultivated species, with a large and tetraploid genome was derived from a unique cross between the wild diploid species A. duranensis (A-genome) and A. ipaënsis (B-genome). In terms of genetic improvement, narrow genetic base of cultivated peanut gene pool, tetraploid, and complex nature of genome are some of the serious bottlenecks. Only limited genetic diversification has been achieved in the past through interspecific hybridization between cultivated peanut and other species of section Arachis. Some attempts have also been made for diversification through development of synthetic tetraploids. Molecular breeding has significant advantages over conventional breeding in less time and with more accuracy. However, to apply the molecular breeding approaches, availability of genetic variation in germplasm, critical mass of molecular markers, genetic maps, and appropriate phenotyping platforms are required. Nevertheless, as a result of concerted efforts of the international peanut community, the last five years have witnessed significant progress in the area of Arachis genomics and some efforts have been initiated towards QTL mapping and molecular breeding for resistance/tolerance for peanut improvement. Molecular breeding have been initiated for several traits for development of superior genotypes. Genome sequence is expected to be available in near future that will further accelerate use of biotechnological approaches for peanut improvement
Technical Abstract: Peanut genomics is very challenging due to its inherent problem of genetic architecture. Blockage of gene flow from diploid wild relatives to tetraploid cultivated peanut, recent polyploidization combined with self pollination and narrow genetic base of primary gene pool resulted in low genetic diversity that has remained a major bottleneck for genetic improvement of peanut. Harnessing the rich source of wild relatives has been negligible due to difference in ploidy level and fear of genetic drag. Lack of appropriate genomic resources has severely hampered molecular breeding activity and this crop remained among less studied crops. Last five years, however, have witnessed accelerated development of genomic resources such as development of molecular markers, genetic and physical maps, generation of expressed sequenced tags (ESTs), development of mutant resources and functional genomics platform that have facilitated identification of QTLs and discovery of genes associated with tolerance/resistance to abiotic and biotic stresses and agronomic traits. Molecular breeding have been initiated for several traits for development of superior genotypes. Genome sequence or at least gene space is expected to be available in near future that will further accelerate use of biotechnological approaches for peanut improvement.