M. MAEKAWA, T. RIKIISHI, T. MATSUURA and K. NODA

Research Institute for Bioresources, Okayama University, Kurashiki, 710-004.6 Japan

A variegated albino, coded 96-1998 al-v. was found in the progeny of a variegated virescent that appeared in the F2 population of a variegated virescent (Shiokari BC5F2) x H-126 (a linkage tester of Hokkaido University). This albino produced six selfed seeds, though one of them failed in germination. Among the five seedlings obtained, three were variegated albinos and two were albinos, and all of them died at seedling stage. However, crosses between the original variegated albino plant, 96-1998 al-v. and two linkage tester lines were successfully made to maintain the variegated albino. To investigate the inheritance of the variegated albino, the F2 population from the cross, T-65 lg x 96-1998 al-v, the F! plant of which was grown at 25°C, was used for genetic analysis. As shown in Table !, the frequencies of albinos and variegated albinos considerably varied among 12 F! panicle-row lines, and three of them contained no albinos. The variation of mutant phenotype frequencies among panicle-row lines was also observed in the F2 population from the cross between the variegated virescent and a normal plant. The frequency of albinos including variegated albinos was 2 1.5%, indicating that the albino character is governed by a recessive gene. The frequency of variegation also varied among Fl paniclerow lines, and 77.4% of the albino plants were variegated. Since the variegation was found in the progeny of a variegated virescent, it is likely that the variegated albino was induced through the same mechanism as the variegated virescent. The linkage analysis

Table 1. Segregation of ig (liguleless), a! (albino) and al-v (variegated albino) in the F2 population consisting of 12 panicle-row lines derived from one F! plant of the cross ‘T-65 ig x 96-1998

1); No. of al and al-v plants/total No. of F2 plants x 100.

2); No. of al-v plants/total No. of a! and al-v plants x 100.

Table 2. Linkage relationship between a! (albino and variegated albino) and ig (liguleless) in the P2 from the cross ‘T-65 ig x 96-1998 al-v’

**; Significant at 1% level. ns; Non-significant.

revealed that the albino gene was linked to ig (liguleless) with a recombination value of 28.3 ± 5.3 on chromosome 4 (Table 2). Two albino genes, a15 and a17 (t), linked to ig on chromosome 4 have been reported (Iwata and Omura 1978). The variegated albino character reported here might be caused by a mutation at either of the loci of a15 or a17(t). Even then, the variegated albino would be useful for analyzing the mechanism of variegation in rice.

References

Iwata, N. and T. Omura, 1978. Linkage studies in rice (Oryza sativa L.). Some albino genes and their linkage relation with marker genes. Sci Bull Fac Agr Kyusyu Univ 33: 11-18.