| dc.description.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. | en_US |
