16. Gene shr-2 located on chromosome 12

Takumi Matsuo, Masahiro Yano, Hikaru Satoh, Nobuo Iwata and Takeshi Omura Plant Breeding Lab., Faculty of Agriculture, Kyushu University, Hakozaki, Fukuoka, 812 Japan


The endosperm mutants, sugary and shrunken, which had been induced by chemical mutagens, were considered to be each controlled by a single recessive gene (Satoh and Omura 1981; Yano et al. 1984). But Yano et al. (1984) identified three genes, su, shr-1 and shr-2, for these mutants. They also demonstrated that su was located on chromosome 12 and shr-1 on chromosome 3.

The location of shr-2 was examined by using the trisomic series of Nipponbare. The mutant line with shr-2 (EM 34) showed a trisomic F\2\ ratio when crossed with the D-type trisomic (trisomy for Nishimura's chromosome 12). The F\3\ seed populations derived from F\2\ disomic plants fitted the 1 (segreg. for shr- 2):1(non-segreg.) ratio as expected (Table 1 Segregation pattern for shrunken-2 in F\2\ and F\3\ seeds of cross with trisomic type D). These experimental results suggest that gene shr-2 is located on chromosome 12.


Table 1. Segregation pattern for shrunken-2 in F\2\ and F\3\ seeds of cross with trisomic type D




References

Satoh, H. and T. Omura, 1981. New endosperm mutations induced by chemical mutagenes in rice, Oryza sativa L.. Jpn. J. Breed. 31: 316-326.

Yano, M., Y. Isono, H. Satoh and T. Omura, 1984. Gene analysis of sugary and shrunken mutants of rice, Oryza sativa L.. Jpn. J. Breed. 34: 43-49.