Genetic Inheritance of Anthocyanin Pigmentation in Rice (Oryza sativa L.)

Abstract

Rice is an important cereal crop that belongs to the grass family Poaceae. A unique feature of purple-coloured anthocyanin pigmentation is possessed by some of the rice varieties and the accumulation of anthocyanin in plants offers resistance to UV radiation and brings out responses to various biotic and abiotic stresses. Knowledge of the inheritance of pigmentation will aid breeders in developing appropriate selection strategies to improve the trait under consideration. In order to study the inheritance of anthocyanin pigmentation, an experiment involving the F1 and segregated F2 populations obtained by crossing the two Oryza sativa subsp. indica varieties, viz., BPT-5204 (non-pigmented) and HY-256 Purple (pigmented), was conducted during three consecutive growing seasons at AICRIP, ARS (Paddy), Sirsi. Hybridization between the female parent, BPT-5204 and male parent, HY-256 Purple, was done during summer 2021 and the seeds obtained from hybridization constituted the F1 generation and were sown during kharif 2021. The same were subjected to selfing to obtain seeds to generate the F2 population, which were evaluated along with the parents and F1 plants during summer 2022. Observations on the presence or absence of anthocyanin pigmentation for different morphological traits, viz., leaf blade, leaf tip, leaf margin, midrib, juncture and junctura back, were recorded in the parents, F1’s and F2 populations in such a way that the presence of pigmentation was recorded as purple, while its absence was recorded as non-pigmented or green. Purple-coloured anthocyanin pigmentation was absent in all the characters in the F1 plant. Similarly, varied segregation for pigmentation was observed and documented in 1276 plants that constituted the F2 generation. The data was analyzed for colour pigmentation to determine the fitness with diverse segregation ratios and to determine the mode of inheritance by chi-square test, which revealed the involvement of two to three genes with different gene interactions.