Marker assisted backcross breeding to develop the drought tolerant version of IR58025B, a popular maintainer line of hybrid rice

Abstract

Drought stress has become more important abiotic factor affecting rice yield under present changing climate conditions. IR58025B is a maintainer line of widely used WA CMS line IR58025A and widely used in commercial rice hybrids production in India. Most of the rice hybrids are released for the irrigated ecosystem consequently, these derived hybrids suffer drastic yield decline under moisture stress conditions. To facilitate the efficient use of complex polygenic traits in hybrid rice molecular breeding research, we undertook development of introgression lines in background of IR58025B with tolerance to moisture stress by introgression of major QTL qDTY3.1 controlling grain yield under moisture stress. The present study reports the development and evaluation of 230 introgression lines (BC2F2) lines in IR58025B background for improvement of grain yield under moisture stress condition. Among 230 ILs, 24 introgression lines were found positive for qDTY3.1 and negative for fertility restoration (rf4 & rf3).Promising BILs exhibited earliness of 7 days under moisture stress with grain yield advantage of 8.54g to 10.78g in comparison to the recurrent parent. This suggested that the efficacy of introgressed drought tolerant QTL qDTY3.1 in enhancing grain yield under moisture stress conditions. Further, breeding lines of IR58025B possessing qDTY3.1 could also serve as good donors for development of drought tolerant rice hybrids for unfavorable ecologies.