Evaluation of the segregation patterns of morphological characteristics of Bg 38 x At 311 cross for high yielding traits of rice

Abstract

In rice (Oryza sativa L.) breeding, evaluation of the segregation patterns of high yielding traits in segregating generations are important for future breeding programs. Bg 38 is a 5–6-month-old, high yielding, photoperiod sensitive, white rice variety with a short round shape grain. At 311 is a 3-month-old, photoperiod insensitive, and red rice variety with a long slender grain shape. The objective of the research was to evaluate the segregation patterns of selected morphological characteristics of the cross between Bg 38 and At 311 for high yielding traits. The research was conducted at Rice Research and Development Institute (RRDI), Bathalagoda during Yala season, 2023 based on selected morphological characters in F2 and F3 populations. Three Ghd7 linked molecular markers namely RM5346, RM5436, and Seq 7-8 were used for the molecular assessment of the segregation patterns. The chi square test (χ²) results indicated a significant (p<0.05) segregation distortion in plant height (7.938) and grain size (18.896) in F2 population. However, a significant deviation from the expected ratio was not observed in basal leaf sheath colour (0.053), apiculus end colour (0.077), and awning pattern (0.018). A significant (p<0.05) segregation distortion was observed in basal leaf sheath colour (4.810), apiculus end colour (6.453), grain shape (16.693) and grain size (19.080) in F3 population. However, plant height, number of tillers, awning, leaf angle, colour of pericarp, colour of lemma and palea did not show significant deviation from the expected ratios. The correlation analysis indicated that plant height showed significant (p<0.01) positive correlation with panicle length (0.449**) indicating plant height as a good morphological marker to predict the panicle length. The polymorphism was observed in RM5436, RM5346 markers and Seq 7-8 was monomorphic. The Dendrogram was constructed using the received banding patterns of two polymorphic and one monomorphic markers grouped the F3 population diversity into four main clusters. In breeder’s perspective segregation distortion is advantageous in selection since it leads to a higher population variation and new phenotypes. This will provide valuable insights into the inheritance of high-yielding traits and assist in advancing rice breeding strategies.