Genetic variability assessment for yield and yield attributing traits in F2 generation of short duration rice (Oryza sativa L.)

Abstract

To overcome challenges imposed unforeseen climate change in rice production, introduction of short duration rice varieties is considered as an effective strategy. In any breeding program for crops, genetic variability is an essential requirement for developing superior cultivar. The objective of this study was to estimate the genetic variability, find out the correlation among the different quantitative traits of F2 generation twelve crosses to identify promising lines that can be used for developing high-yielding short-duration varieties, which are better suited for the Low Country Wet Zone (LCWZ) of Sri Lanka. The experiment was laid as a randomized population method and fifty plants were selected randomly for data collection in each population at the Rice Research Station, Labuduwa, Sri Lanka. The data were recorded on eighteen different agro-morphological traits. The F2 crosses showed a varying response for days to heading, flowering and maturity. The majority of F2 crosses reaches 50% flowering less than 65 days, of which Ld 253/Bg 252, Bg 308/Bg 252, At 311/Bg 252, At 309/At 311 and At 311/At 309 F2 crosses reached this stage within 60 days. Therefore, these crosses pose the ability to complete their crop cycle relatively within a short duration. When considering the yield performance, At 311/Bg 252 and At 311/At 309 F2 crosses showed higher number of effective tillers (10 and 12), thousand grain weight (17.38g and 18.9g) and yield per plant (16.82g and 21.8g), Genetic variability assessment indicated that above mentioned important yield attributing characteristics also showed a higher phenotypic coefficient variance and genotypic coefficient variance for all F2 crosses. High heritability coupled with high genetic advance were also observed for above traits. Correlation analysis revealed that seed per panicles(0.203*),thousand grain weight(0.331**) and panicle length( 0.129*) had the significantly positive contribution to grain yield. Overall, results indicated that among the F2 crosses evaluated At 311/Bg 252 and At 311 / At 309 crosses can be considered as promising lines to develop short duration high yielding varieties adaptable for LCWZ of Sri Lanka. However, comprehensive physiological studies need to be conducted to investigate the adaptability of these crosses to the variable climatic conditions of LCWZ.