Haus, p. 132

IV.3. Coordinator's report: Chromosome 4.

T. E. Haus. Department of Agronomy, Colorado State University, Fort Collins, Colorado 80521, U.S.A.

1. gl and gl2 have been found to be allelic in reciprocal crosses between these mutants (Haus and Tsuchiya. 1972. BGN. 2:78).

2. There are conflicting reports of lg genes on chromosome 4 in the supplement I and supplement II linkage summaries by Robertson, et al. lg2 reported by Immer and Henderson in supplement I, is a non-viable light green mutant and had close linkage with the k locus. In supplement II lg2 is missing from chromosome 4 and lg3, reported by Hanson and Kramer as a non-viable light green, is on the chromosome map. No mention is made in this supplement of changing gene designation of lg2 to lg3. We are in the process of using a chromosome 4 trisomic to associate our light green stocks with that chromosome. So far we have associated one light green stock designated in our laboratory as lg9 with chromosome 4. This is a viable light green mutant and is possibly the lg4 locus.

3. In attempting to determine the centromere location on chromosome 4 we are using a telotrisomic chromosome 4 stock in crosses with chromosome 4 mutants. So far, we have obtained trisomic ratios with f9 and disomic ratios with zbc (Tsuchiya, 1972, BGN, 2:92). In BGN, Vol. 1 (p.61-62) Tsuchiya reports that gl, gl2 =gl, br2 and yh all have disomic ratios in crosses with Telo 4A.

4. The chromosome map for chromosome 4 is as follows:

This arrangement seems to best fit all data for this chromosome. br2 and gl3 are two additions to the chromosome (Takahashi, 1971, BGN. 1:51-58) since last published in Barley Genetics II.

5. Three genes studied by Takahashi, yh, hs and sh and located on chromosome 4 by trisomic analysis have not shown linkage with other markers on chromosome 4. From available data, it would appear that these three genes are distal to bl.

Other associated genes are cer-j, reported by Søgaard. (BGN. 1:41-47); ms-r and ms-v reported by Hockett and Eslick (Barley Genetics II: 298-307); gs 1 reported by McProud and Eslick (BGN. 1:168-169); ert-i and int-c reported by Persson (Barley Genetics II:430-433).

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