Soybean is the most important grain legume in the world in terms of production and international trade. It is economically important leguminous crop for oil, feed and soy food products and has occupied a coveted place among the oilseed crop being cultivated in India. In India it is cultivated over an estimated area of 9.95 million ha and production is around 12.57 million tons which is well below world average. One of the major limitations for increasing the productivity of soybean is non availability of resistant varieties for disease and pest. Soybean rust is a fungal disease caused by Phakopsora pachyrhizi, commonly known as Asian soybean rust. This disease causes yield losses up to 80 percent. Early symptoms include yellow mosaic discoloration on upper surface of older foliage and in later stage it causes lesions on the leaves of soybean plants. The infected plants undergo defoliation and early maturation in relation to non-infected plants, which causes reduction in weight and quality of the grains. Due to the limited availability of resistant varieties, the fungicide application is the only management tool available for farmers, which significantly raises the production cost and the risk of environmental and human contamination. Thus, development of soybean rust resistant varieties will help to increase the yield.
Soybean rust has been controlled through the deployment of single resistance genes called Rps (resistance to ………..). However, such resistance is not durable and is easily overcome by the changing pathogen population. Therefore, it is of paramount importance to search for and identify new rust resistance genes in new soybean cultivars.
DNA molecular markers are powerful tools in selecting for traits of interest in breeding programs. They are especially important in breeding for complex traits such as resistance to disease such as soybean rust. Therefore, we propose to employ molecular marker and genomics technologies to manage Phakopsora pachyrhizi disease in soybean. Successful execution of this study should provide disease resistance DNA markers for rapid screening and identification of high-yielding soybean lines with high levels of disease resistance. Soybean rust, incited by Phakopsora pachyrhizi, is the most serious soybean disease ofeconomic importance in the Orient.