A yellow streak mutant, derived from sodium azide treatment, was selected in an M2 population of 'Glenn' barley (Faue, 1987). Leaves of plants with this trait were yellow-green with pronounced vertical streaks, similar to yst2 plants. Maturity of the plants was delayed by one to two weeks. For this report, the mutant gene is identified as yst,,d. This yellow streak mutant was tested for allelism with the three known yellow streak stocks yst (BGS 104), yst2 (BGS 109), and yst3 (Lion) reported to be inherited independently (Singh and Tsuchiya, 1973). The yst,,d parents used in the crosses to yst and yst2 were F3 selections from R.I. Wolfe's Multiple Dominant (MD)/Hector//yst,,d. The yst2 parent was an F2 selection from the cross OUM5 (lzd)/BGS 109. An F3 selection from Bowman/3/MD/Hector//yst,,d was crossed to the yst3 stock. Individual plants used for crossing expressed the appropriate yellow streak trait.
F1 plants from all three crosses were green, F2 progeny rows were evaluated from the crosses with yst and yst2. Heterogeneity chi-square values were not significant and progeny rows within a cross were combined. F2 segregations and values for fit to 9 green : 7 yellow streak ratio are presented in Table 1. Expression of yst,,d was poor in the F2 progeny from the yst3 cross. The data indicate that the yst,,d gene is nonallelic to mutant genes at the three known yellow streak loci. Thus, the allele symbol yst4d is suggested for the yst,,d gene and yst4 for the locus.
Plants selected from the cross Bowman*3/3/MD/Hector//st,,d have received three doses of Bowman, a two-rowed cultivar, as recurrent parent. Yet, most yellow streak segregates had the six-rowed trait of the Glenn parent. This suggests that yst4d is linked with the v allele found on chromosome 2.
Faue, A.C. 1987. Chemical mutagenesis as a breeding tool for barley. M.S. Thesis, North Dakota State University, Fargo, ND.
Singh, R.J., and T. Tsuchiya. 1973. Allelism testing among three yellow streak mutants. BGN 3:54-55.