Application of molecular markers to improve drought tolerance and yield enhancement in upland rice

Abstract

Upto now, a lot of drought related genes were cloned and individual gene showed positive effects under controlled stress experiments, but were not effective in the field. However, the progresses by conventional breeding approaches were achievable as some drought varieties have been released to the farmers in the recent years. Although, this is not adequate to cope up with the future demand of high yield for rice, as drought seems to spread to more regions and seasons across the country. Therefore, marker assisted selection came into lime light for accelerating and giving pace to plant breeding. The identification of QTLs with a major effect on grain yield raises a new hope of improving grain yield under drought through marker assisted breeding. The availability of the major effect QTL for drought tolerance, a theoretical frame-work for marker assisted selection and the existence of intolerant varieties that are widely accepted by farmers provides an opportunity to develop cultivars that would be suitable for larger areas of drought prone rice. In case of (Sarjoo - 52 × Birsa Gora) × Sarjoo - 52, two drought tolerant genes were incorporated. Only those plants were therefore selected which showed polymorphism for the genes MQTL_1.1 and qDTY_3.2. Thus, plant number SA – D – 1, SA – D – 7, SA- D – 8, SA – D – 9, SA – D – 13, SA – D - 27 and SA – D – 56 were selected. These lines have been subjected to further breeding and trial tests. Agronomic performances and physiological behavior of these lines are also under track. The results showed that the variety Sarjoo – 52 could be efficiently converted to a drought tolerant variety in a backcross generation followed by selfing and selection, involving a time of two to three years. Polymorphic markers for foreground and background selection were identified for the high yielding variety to develop a wider range of drought tolerant variety to meet the needs of farmers in the drought-prone regions. This approach demonstrates the effective use of marker assisted selection for a major QTL in a molecular breeding program.