II. 21. Genetic analysis with acrotrisomic 1L^1S.

T. Tsuchiya and J. Fujigaki (1), Department of Agronomy, Colorado State University, Fort Collins, Colorado 80523, U.S.A.

(1) Supported by USDA/SEA Competitive Research Grant 5901-0410-9-0334-0 to T. Tsuchiya.
(2) Visiting Associate Professor, Leave of absence from Tokyo University of Agriculture, Tokyo, Japan.

Acrotrisomic 1L^1S (Tsuchiya, 1979) was crossed with a triple genetic marker stock f8 lk2 n, to study the nature of the deficiency in the long arm of the acrocentric chromosome. Although the exact length of the deficiency in the long arm has not been measured, it is obvious that a deficiency exists. The order of three genes in 1L is f8 (108 unit) - n(l21) - lk2(130) with f8 closer to the centromere which is somewhere at 100 unit (Takahashi and Fukuyama, 1977). The genetic segregation data are shown in Table 1.

Table 1. Segregation ratios in F2 populations in crosses of acrotrisomic 1L^1S X a triple recessive stock, f8 lk2 n.

It is obvious from the data (Table 1) that f8 and lk2 are on the missing segment of the long arm. The data for n seem to show trisomic segregating ratios with lack of recessive homozygotes in the trisomic portion although several trisomic plants were not available for the study of n gene because of complete sterility.

More data are needed to determine the nature of the deficiency.

References:

Takahashi, R. and T. Fukuyama. 1977. Linkage maps and gene list in barley. pp. 391-416. In Plant Genetics, IV. Morphogenesis and Mutation, Chapter 4, Gene List and Linkage Maps. (ed. H. Yamaguchi), 517 pp. Shokabo Publ. Co., Tokyo, Japan (Japanese).

Tsuchiya, T. 1979. Acrocentric chromosome 1L in barley. Barley Genetics Newsletter 9:101-102.

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