Identification and Molecular mapping of novel Bacterial leaf blight resistance genes in rice

Abstract

Rice (Oryza sativa L.) is the most important crop of India and is grown all over the country in diverse ecosystems. It is agronomically and nutritionally, most important food crop of the world serving as the staple food for nearly 2.4 billion people. It plays a pivotal role in Indian economy being staple food for two thirds of the population. With 44.62 million hectares planted to rice, India ranks first in area and second in production (96 , million tons). 21% of the total calorie requirement in the Indian diet is being supplied by k~~ \P~rice. It is a member of the Gramineae family, has a genome size of 0.45 XI09 bp '~ tArumunagathan and Earle, 1991), which is one tenth the size of the human genome and I,tY> '® i, • modo! 'y,tom fo< ",,,I .,nom' 'Mly,i,. Oiff",nt .,notyp" of ,i" .re .d.pl,d to • ~ l ~ ~ ~ ~ wide range of environmental conditions from tropical flooding to temperate dry land, making it an excellent example for real-life, adaptive responses. The production of rice in India has shown an increasing trend from 83 million tonnes to 93 million tonnes during 1997-98 to 2001-02 (http://www.fao.orgirice2004/eni pdf/nigam.pdf), and is presently around 96 million tonnes. But future projections indicate that the current levels of production may not be sufficient to feed the ever increasing population in our country. In order to meet the food demands for the future, concerted efforts are required to increase the rice productivity and minimize production losses due to pests and diseases. Even though the introduction of high yielding varieties (HYVs), development and adoption of modern rice production technologies have led to progressive growth in rice production, it also inadvertently increased the genetic