DEVELOPMENT OF BLAST RESISTANT SUPERIOR FRAGRANT RICE LINE THROUGH HYBRIDIZATION PROGRAM

Abstract

Two pieces of research works were conducted for generating blast resistant fine aromatic rice through crossing technique using landraces viz., BRRI dhan34 as susceptible, Kataribhog and Radhunipagol as resistant sources during June to December, 2017 in Dinajpur. A field research work was conducted in Randomized Complete Block Design with three replications for assessing data on per plant of different disease parameters and yield contributing characters at different days after transplanting (DAT), and yield. A crossing experiment was driven in pot in-vitro condition. In field study, BRRI dhan34 exhibited the highest number of spots (68.40), percent leaf blast severity (11.73), number of death leaf (6.33), neck blast (2.20), node blast (6.20), collar blast (4.33), death panicle (2.07), number of tillers (32.67), number of effective tillers (29.73), spikelet per panicle (287.13), 1000-grain weight (27.52) and yield per plant (68.64). The mean squares of the three cultivars exhibited strong and significant variations for all of the selected characters except number of death leaf. The genotypic variance (Vg), phenotypic variance (Vp), genotypic coefficient of variation (GCV), phenotypic coefficient of variation (PCV), heritability (h2 ), genetic advance (GA) and percent genetic advance (GA%) were estimated where the PCV values were higher than corresponding GCV values for all of the selected characters. In comparison, the highest heritability value (h2 =99.83%) was estimated for plant height whereas the lowest heritability value (h2 =40.08%) was estimated for number of death leaf. The highest genetic progress was 81251.23% for collar blast and 79664.90% for number of spots. Number of effective tillers per plant exhibited significant and positive correlation with number of tillers, number of spots, percent leaf blast severity, neck blast, node blast, collar blast, number of death panicle, spikelet per panicle and yield. Number of spots, percent leaf blast severity and neck blast asserted significant and positive correlation with, node blast, collar blast, number of death panicle, spikelet per panicle and yield. The direct and indirect effects were partitioned among different phenotypic characters as well as disease parameters. Among the phenotypic characters, the highest positive direct effect was revealed in panicle length (0.190) followed by spikelet per panicle (0.176) on yield. Among the disease parameters node blast per plant showed positive direct effect (0.227) on yield. Number of spots revealed highest indirect effect on yield via node blast (0.164). Number of spot (- 0.014), death leaf (-0.162) and death panicle (-0.015) exhibited negative direct effect on yield. In crossing, F1 generations (7) were developed from the cross between BRRI dhan34 and Kataribhog, and BRRI dhan34 and Radhunipagol. The outcome of the study suggesting the best “black box” approach in breeding program for developing disease resistant fine aromatic rice where the number of spots and percent leaf blast severity responded highly genetical transmissible character resulting highly positive significant correlation in yield contributing characters.