DEVELOPMENT OF RICE GERMPLASM BASED ON GENETIC VARIABILITY IN F5 SEGREGATING POPULATIONS

Water scarcity is a global dilemma, and rice crop needs plenty of water for optimum growth and yield. In the current climate change scenario, developing a broad-based gene pool of rice to help the crop breeders develop high-yielding cultivars needs dire action. This study assessed the genetic variation among 10 diversified parents and their 15 F5 populations developed under limited water supply for various morphological traits. Parents and F5 populations showed significant differences at 5% and 1% for most of the studied maturity and yield traits. F5 population ‘Dokri-Basmati/DR-92’ exhibited earliest for days to heading (93) with the highest culm length (85.5 cm). Maximum flag leaf area (34.67 cm2) resulted for the F5 population ‘DR-83/NIAB-IRRI-8.’ On the other hand, the F5 population ‘DR-83/DR-92’ excelled in performance for the number of primary branches panicle-1 (11). F5 population ‘IR-8/NIAB-IRRI-9’ displayed the longest panicle (28.70 cm) with the highest number of secondary branches panicle-1 (38). Three of the F5 populations ‘DR-92/DR-83,’ ‘DR-83/NIAB-IRRI-8,’ and ‘NIAB-IRRI-9/IR-8,’ displayed maximum heritability for panicle length (0.82), the number of primary branches (0.80), and secondary branches panicle-1 (0.94), respectively, offering the prospects for development of potentially high-yielding variety. The highest genetic advance for panicle length (9.87%) emerged from the F5 population ‘DR-92/DR-83,’ which also had the highest heritability for this trait. F5 population ‘DR-83/DR-92’ manifested maximum genetic advance (3.32%) for primary branches panicle-1, while ‘NIAB-IRRI-9/IR-8’ revealed the highest genetic advance (6.26%) for secondary branches panicle-1. Both of these populations may be suitable for developing the spreading type of rice germplasm with the potential water stress. F5 populations displayed differential responses for the studied traits, with none of the segregating populations excelling for studied maturity and yield traits. However, the germplasm pool created can serve as a better collection for improving existing populations from a production traits perspective under water-stress conditions or developing new cultivars focusing these traits for the target water stress region(s).