Genetic Analysis and Mapping of a Thermo-sensitive White Stripe-Leaf Mutant at Seedling Stage in Rice ( Oryza sativa)

Abstract

A thermo-sensitive white stripe-leaf mutant ( tws) was selected from the M 2 progeny of a japonica variety, Jiahua 1, treated by 60Co γ-radiation. In comparison with the wild type parent, the mutant displayed a phenotype of white stripe on the 3rd and 4th leaves, but began to turn normal green on the 5th leaf when grown at low temperatures (20°C and 24°C). Furthermore, the content of total chlorophyll showed an obvious decrease in the leaves with white stripe. These results suggest that the expression of the mutant trait was thermo-sensitive and correlated with the leaf age of seedlings. The genetic analysis indicated that the mutant trait was controlled by a single recessive nuclear gene, designated as tws. In addition, by using SSR markers and an F 2 segregating population derived from the cross between the tws mutant and 9311, tws was mapped between the markers MM3907 and MM3928 with a physical distance of 86 kb on rice chromosome 4.