Vol. 11, Special Issue 6 (2022)

Author(s):
Kavitha G, Reddi Sekhar M, Mohan Reddy D, Reddy VLN, Kalyani MB, Sudhakar P and Senguttuvel P

Abstract:
Low phosphorus stress has become more important abiotic factor affecting rice yield under present changing climate conditions. KMR-3R is one of the popular restorer line used in commercial rice hybrids production in India. Most of the rice hybrids released for the diverse ecosystem conditions using three-line system for normal phosphorus conditions. Consequently, these derived hybrids suffer drastic yield decline under low phosphorus 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 KMR-3R with tolerance to low phosphorus stress by introgression of major QTL Pup1 controlling grain yield under low phosphorus stress. The present study reports the development and evaluation of 250 introgression lines (BC₂F₂) lines in KMR-3R background for improvement of grain yield under low phosphorus stress condition. Among 250 ILs, 26 introgression lines were found positive both for Pup1 and Rf4. Promising BILs exhibited earliness of 15 days under low phosphorus stress in comparison to the recurrent parent. Grain yield advantage of 7.72 g to 10.05 g was recorded among selected BILs compared to KMR-3R under low phosphorus stress condition. This suggested that the efficacy of introgressed low phosphorus stress tolerant QTL Pup1 in enhancing grain yield under low phosphorus stress conditions. Further, breeding lines of KMR-3R possessing Pup1 could also serve as good donors for development of tolerant rice hybrids under low phosphorus stress.