Development of elite doubled haploid Rice line with resistance to bacterial Leaf blight using molecular markers

Abstract

Rice (Oryza sativa L.) is one of the most widely cultivated tropical cereal and is a major carbohydrate source for more than half of the world s population. India is the second largest producer of rice with an annual production of 165.70 million tonnes. About 49.78 million hectares of land is under rice cultivation in India. The first breakthrough in increasing rice yield was happened during 1980 s through the introduction of semi-dwarf varieties. Rice production must be increased to meet the demand of the growing population. Ever changing climate factors and emergence of virulent pests and diseases render the widely adopted new varieties unable to deliver their yield potential. Among the biotic stresses in rice, diseases cause severe crop yield losses. Bacterial leaf blight (BLB) disease is one of the most threatening disease affecting rice production in India and elsewhere. The yield losses may go up to 81 % under severe infection. Control of BLB using chemical measures are ineffective. Hence, utilization of host plant resistance mediated through the resistance genes is the most effective and environment friendly approach for the management of BLB pathogen. To obtain sustainable production, there is a immediate need of adopting newer technologies in crop improvement. Hybrid rice holds significant yield advantage over inbred lines, but its adoption rate is very slow in India. Even though rice hybrids can increase the yield by 15 to 20 % over inbred varieties, the grain quality traits tend to be inferior and this is the major reason for poor doption of hybrid rice technology in India. This is due to the male parent (R-line) used. Hence improvement of R-line is an essential requirement for exploiting the yield potential of hybrid rice with good grain quality. newline