Identification of Transgressive Segregation for Yield and Resistance to Yellow Stem Borer (Scirpophaga incertulas Walker) in F2 Segregating Generation of Six Rice Crosses (Oryza sativa L.)

The research investigation on the occurrence of transgressive segregation in F2 populations derived from six rice crosses namely: ADT 43 X TKM 6, ADT 43 X ASD 12, ADT 45 X TKM 6, ADT 45 X ASD 12, ASD 16 X TKM 6 and ASD 16 X ASD 12 with the aim of identifying superior genotypes for yield and resistance to the yellow stem borer (Scirpophaga incertulas). This research was conducted through series of field observations for transgressive segregants at Plant Breeding Farm, Department of Genetics and Plant Breeding, Faculty of Agriculture, Annamalai University during Kharif season of 2022. The crosses involved high-yielding but susceptible female parents (ADT 43, ADT 45, ASD 16) and YSB resistant but low yielding male parents (TKM 6, ASD 12). In the F2 generation, a wide range of phenotypes was observed for yield-related traits and YSB resistance. Twelve superior transgressive segregants were identified in each cross, exhibiting increased grain yield per plant, number of productive tillers, and number of grains per panicle, coupled with high levels of resistance to YSB. The results suggest that the parents carried different alleles and genes governing yield and its component traits, allowing the accumulation of favorable alleles in the F2 progeny through recombination. The identification of these high-performing transgressive segregants provides opportunities for further evaluation and potential use in rice breeding programs to develop improved cultivars with enhanced yield and biotic stress resistance.