Fundamental studies on rice breeding through hybridization between Japanese and foreign varieties. : XIII.On the C-gl linkage relation in the progeny of the cross, Surjamkhi×Norin No.1

Abstract

The authors reported already that duplication and deficiency of C-locus which bore the gene responsible for the production of chromogen in the rice plant occurred in F₂ of the cross, SurjamkhixNorin N0.1, and that it might be due to cryptic translo-cation or inversion (recombination value : ca. 50 per cent) of the gene locus (MIZUSHIMA and KONDO, 1959, '60). In the present paper reports the result of investigation of segregation in respect to C and gl genes in F₂ of the cross, F₅ (Surjamkhi x Norin No. 1) XHokkaimochi No. 1. The F₅ plants used consisted of five having nonglutinous endosperm and colored glurme apiculus, and showed the effects of the dominant C- and glgene. One of them, however, was confirmed previously to have doubled C-loci, of genotype C^BC^B₁APgl⁺ (KONDO and MIZUSHIMA, 1964 b). A is the gene which converts the chromogen into anthocyanin and P distributes anthocyanin to the site of apiculus in glume. Hokkaimochi No. I has glutinous endosperm and colorless apiculus whose genotype has been identified as C⁺A⁺pgl. In F₂ C^BC^B₁APgl⁺ X Hokkaimochi No. I a clear linkage relationship was observed between C- and gl-gene. However, it was difficult to determine which of the two C-genes, C^B and C^B₁, was linked to gl. In the other three crosses the C-gl linkage was also confirmed and the recombination value was almost the same as reported by other workers (CHAO, 1928 ; NAGAO, 1951 ; JODON, 1957). From the linkage between C and gl observed in the present experiment we consider that duplication and deficiency of C-locus in the hybrids reported is not due to its cryptic translocation. However, the possibility of change in position of C-locus from one side of gl-locus to the other by inversion, keeping a linkage relationship between the two, still remains. This was discussed briefly from the tetrasomic segregation of C-gene already observed in the hybrids one of whose parent was Surjamkhi (KONDO and MIZUSHIIMA, 1964a) we concluded that the cause of duplication and deficiency is more probably atributable to a peculiar modes of conjugation of chromosomes bearing C-locus than tonversion as already suggested previously (KONDO and MIZUSHIMA, 1964 b).