Genetic analysis and molecular mapping of Rp, a mutant gene encoding red pericarp in rice (Oryza sativa L.)

Abstract

Coloured rice has pigments deposited in the grain pericarp; red rice is the most common type of coloured rice. Red rice is rich in essential nutrients and has been grown and consumed in China for a long time. In this study, we report the genetic characterisation and preliminary molecular mapping of a mutant gene encoding red pericarp in rice (Oryza sativa L.). To analyse the genetic basis of the red pericarp mutant, a reciprocal cross between GER-3 (red pericarp, indica cv.) and 898 (white pericarp, indica cv.) was made. The genetic analysis results confirmed that there was only one dominant gene, temporarily designated Rp (Red pericarp) controlling the segregation of the red pericarp in the F<sub>2</sub> population. For the molecular mapping of Rp, an F<sub>2</sub> population derived from an inter-subspecific cross between Gene Engineering Rice-3 (GER-3) and C418 (japonica cv., white pericarp) was constructed. The genotype of the pericarp colour of the F<sub>2</sub> individuals in the mapping population was validated by progeny testing of the F<sub>2:3</sub> families. Simple sequence repeat (SSR) markers and the bulked segregation analysis (BSA) method were used; Rp was mapped to the short arm of chromosome 7 between the SSR markers RM21182 and RM21268, with a genetic distance of 3.5 and 12.0 cM, respectively. In this paper, the potential origin of the red pericarp mutant gene Rp was also discussed.

Genetic variability of mutant rice (Oryza sativa) genotype induced by gamma rays

“…Genetically, the black rice's pericarp traits were controlled by a dominant gene, and a recessive gene controlled the white rice's pericarp. Tong et al (2021) confirmed that only one dominant gene, temporarily designated Rp (Red pericarp), controlled the segregation of the red pericarp in the F2 population. Wang et al (2020) stated that the gene resources of red rice containing anthocyanin are of great value for developing nutritious, high-anthocyanin-content rice.…”

“…According to Tong et al (2021), the segregation ratio of the red pericarp individuals to the white pericarp individuals was 3:1. Single dominant gene is responsible for the red pericarp of GER-3, and the red pericarp expression of the mutant gene Rp is not affected by the cytoplasm.…”