Genetic variability and crossing among blast resistant and susceptible fine aromatic rice (Oryza sativa) land races

摘要

Blast is a serious threat in rice production worldwide. For this, a field research was conducted to study the variability of blast disease and yield parameters and to generate a blast resistant fine aromatic rice from June to December 2016 using blast susceptible genotype BRRI dhan 34 and blast resistant genotypes Zotakatari and Kalijira. The data were assessed on eight yield and yield contributing characters and four blast disease parameters. The results indicated that BRRI dhan 34 had the highest number of tillers per plant (29.20), length of leaf blade (60.80 cm), number of spots per plant (94.47), number of death leaf per plant (6.20), number of effective tillers per plant (23.93), panicle length (25.20 cm), number of spikelets per panicle (153.3),1000-grain weight (27.52 g), number of spots per plant and yield per plant (3.251 g). The mean squares of the three cultivars exhibited strong and significant differences for most of the characters studied. The phenotypic variance (Vp) and phenotypic coefficient of variation (PCV) were higher than genotypic variance (V) and genotypic coefficient of variation (GCV), respectively. The higher heritability (h2b) was exhibited for all traits. Very high phenotypic and genotypic coefficients of variation werefound in number of spots per plant. The strongest significant and positive correlation was exhibited between plant height and length of leaf sheath (0.84***) followed by yield per plant with spikelet per plant (0.71). Among the disease parameters per cent leaf blast severity showed higher positive direct effect (0.369) on yield and highest indirect effect on yield via number of spots per plant (0.251). In crossing, number of successful pollinated panicle was low (5%). Therefore, the seeds of successfulcrossed plants would be used for backcrossing of transfer blast resistant gene in blast susceptible genotypes.