GrainGenes

II. 23. Primary trisomic analysis of a mutant "gigas" in barley. (1)

J. W. Shim, (2) E. Furst and T. Tsuchiya, Department of Agronomy, Colorado State University, Fort Collins, Colorado 80523, U.S.A.

(1) Supported in part by USDA/SEA Competitive Research Grant No. 5901-04109-0334-0, USDA/SEA-CSU Cooperative Research Grant No. 58-9AHZ-2-265 to T. Tsuchiya and CSU Hatch Project.

(2) Visiting Professor, Leave of Absence from Seoul National University, Suewon, Korea.

"Gigas" mutant (KM72) was induced in a two-rowed barley variety, Tochigi Golden Melon, by radiation treatment (Tsuchiya, unpublished), and found to be allelic to sf (female sterile) of Harvey et al. (1968) (Tsuchiya, 1975).

The mutant is slightly taller than the control variety. Spikes are larger, slightly less compact than the control with heavily waxed florets, longer lemma and palea, shorter awns. Stigmas are less feathery (less branched stigmas) resulting in high sterility without artificial self pollination. Seeds are much smaller than control and semi-naked. After heading the mutant plants are readily identified from the normal plants.

The mutant was crossed with primary trisomic Pseudonormal (Triplo 5). F2 seeds were harvested from trisomic F1 hybrids. Chromosome numbers of F2 plants were studied and the segregation for "gigas" mutants was studied at heading time (Table 1).

Table 1. F2 segregation in Triplo 5 X "gigas" mutant.

The segregation for the total population (+:gigas = 110:48) fits well to a 3:1 ratio (X² 3.1 = 2.44). An appreciable number of recessive homozygotes (12 of a total of 48 trisomics) were found in the trisomic portion indicating that the gene for "gigas" mutant is not carried by chromosome 5.

References:

Harvey, B. L., E. Reinbergs and B. H. Somaroo. 1968. Inheritance of female sterility in barley. Can. J. Plant Sci. 48:417-418.

Tsuchiya, T. 1975. Allelic relationships of some morphological and chlorophyll mutants in barley. BGN 5:64-67.

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