Stability analysis for grain yield and quality traits in indica rice (Oryza sativa L.) lines
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Date
2018-08-29
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Department of Plant Breeding and Genetics, BAU, Sabour
Abstract
The present study was undertaken with the objective to determine the nature and magnitude of genetic variability, heritability and genetic advance, degree of association among yield and quality traits, direct and indirect effects, genetic diversity on the basis of morphological and molecular level, phenotypic stability among 36 advance indica rice lines including 3 checks for 21 yield and quality attributes. The trials were conducted in randomized complete block design (RCBD) with 3 replications and 4 environments (including control and reproductive stage drought stress conditions) during kharif 2014 and kharif 2015. The analysis of variance indicated highly significant differences for the majority of traits studied except few quality traits which indicated the significant differences among these rice lines. In congruence with the previous reports, phenotypic variance (VP) and phenotypic coefficient of variance (PCV) were higher than the genotypic variance (VG) and genotypic coefficient of variance (GCV) subsequently which indicated the influence of environment on the development of the characters. Moderate values (10-20) of GCV and PCV was observed for some traits hence; selection for these traits may be ambiguous if we adopted for its improvement. The higher magnitude of GCV was observed for number of spikelets per panicle, kernel elongation ratio and head rice recovery while maximum PCV was observed for number of spikelets per panicle, harvest index and number of tillers per plant. High heritability along with higher magnitude of genetic advance as percent of mean was observed for the traits namely; number of spikelets per panicle, head rice recovery and kernel elongation ratio which revealed the preponderance of additive gene action in the inheritance and these traits could be improved through direct selection as GCV is also comparatively high for such traits. Positive or negative significant association with higher positive or negative direct effect were observed for the traits viz; plant height, biological yield per plant and harvest index which indicated the effectiveness of these traits for utilization in future rice breeding programmes. Genetic divergence among rice lines showed sufficient amount of genetic diversity hence, crossing among the divergent lines grouped in different clusters would produce superior hybrids and valuable transgressive segregants with higher genetic advance. The molecular diversity also validated the morphological differences among these rice lines and higher PIC values of the markers indicated their utility in explaining the genetic diversity. In case of phenotypic stability on the basis of stability parameters for grain yield per plant, IR 92521-24-5-1-3 was found stable line across all the environments and had maximum grain yield per plant, earliest in days to 50% flowering, better maturity duration, maximum number of spikelets per panicle, good head rice recovery, moderate L/B ratio and it also performed better than all three checks therefore, such line can be recommend to farmers or variety release proposal. Rice line IR 92545-53-4-1-3 was identified for unfavourable or poor environment while IR 92546-17-6-4-3 and IR 92546-17-6-4-4 lines was identified for rich or favourable environment.