Distribution of the genes causing F2 chlorosis in rice cultivars of the Indica and Japonica types

Abstract

Chlorotic plants were segregated in F2 populations in varietal crosses of common rice. The genetic basis and distribution of the genes causing F2 chlorosis in native cultivars were studied to examine the role of the F2 chlorosis in varietal differentiation of rice. It was proven that this F2 chlorosis was controlled by a set of duplicate genes, hca-1 and hca-2. The hca-2 gene was widely distributed in native cultivars of the Japonica type, while many Indica types carried its dominant allele hca-2+. Japanese cultivar J-147 carried hca-2. The hca-1 gene was frequently distributed in cultivars containing the Hwc-2 gene for F1 weakness. We concluded that F2 chlorosis does not cause or promote varietal differentiation in rice.