Improving Adaptability of IR-64 to Aerobic Condition through Introgressing Root and Water Use Efficiency (WUE) by Marker Assisted Backcross Breeding (MABC)

Introgression of roots (water mining) and water use efficiency (WUE) traits on to a single elite genetic background is needed whiledeveloping aerobic worthy rice cultivars. Considering the complexity of inheritance of these traits, a focused molecular breeding is a promising approach. An effort was carried out to introgress these complex traits into an elite mega variety IR-64. A set of 540 DBC₃F₂ lines were evaluated for days to flowering, panicle sterility, total dry matter accumulation yield and HI under aerobic condition. Early flowering in introgressed lines had advantage over late flowering which can support biomass accumulation and partitioning of photosynthates and there by reduction in panicle sterility. The results indicated that the trait introgressed lines had 20percent higher total dry matter and 35 percent higher yield than the recurrent parent IR-64, indicating introgressing the suitable drought adaptive traits can improve the productivity of rice under semi-irrigated condition without concomitant reduction in productivity.