SELECTION IN ADVANCED GENERATION (F4) BASED ON AGRO-MORPHOLOGICAL TRAITS IN FINE RICE

Abstract

The experiment was conducted at Plant breeding Research Field during transplant Aman season (July-December) of 2016. The experimental materials comprised with 32 advanced generation (F4) derived from eight crosses involving six fine rice parental lines. A total of thirteen characteristics viz. plant height (cm), productive tillers/hill (maximum vegetative stage), panicle length (cm), fertile grains/panicle, sterile grains/panicle, panicle weight (g), sterility percentage (%), lodging percentage (%), 1000-grain weight (g), grain yield/hill (g), days to 50% flowering, days to maturity and harvest index were studied to assess genotypic and phenotypic correlations and genetic diversity pertained among the advanced lines. The analysis of variance showed significant difference among each of the selected traits in the advanced lines. The means of different traits were separated by DMRT test, the advanced line, PL6 derived from Kataribhog x Chinigura produced the highest grain yield/ hill (41.51g) but ranking of the advanced lines based on yield enhancing traits, PL5 derived from the same cross showed the best performance. Among the 13 characteristics, fertile grains per panicle, panicle weight and 1000-grain weight exhibited positive and significant correlation with grain yield both at genotypic and phenotypic levels, suggested inherent association of these traits to increment grain yield in the advanced lines. All the 32 advanced lines were incorporated in the genetic diversity analysis based on 13 traits. The lines were distributed into six clusters; cluster II comprised with eight lines and the cluster V only with two lines. The intra-cluster distance was maximum (1.232) in the cluster V, indicated two advanced lines included in the cluster were relatively more diversified from each other. The inter-cluster distance (16.594) was between the cluster I and V. Therefore, further genetic diversity might be extended through crossing or direct selection of promising parental lines. Since the main objective of breeding is to increase yield potential in advanced lines, cluster mean of the traits must be taken into deliberation. Accordingly, the cluster I might be deliberately selected to improve yield potential in the advanced lines. The simultaneous consideration character association both at genotypic and phenotypic levels and genetic and genetic diversity fertile grains per panicle, panicle weight and 1000-grain weight along with the advanced line, PL6 may be included in further breeding to evolve super quality fine rice varieties suitable for our country.