II. 16. Spring habit mutants in barley.

Yasuo Ukai, Institute of Radiation Breeding NIAS, Ohmiya, Naka, Ibaraki 319-22, Japan.

From a hulled winter cultivar Chikurin Ibaraki 1, 87 early maturing mutants have so far been obtained with different mutagenic treatments. Vernalization tests of the mutants showed that 14 among them have complete or incomplete spring habit (Table 1). When Ea 4, 6, 7a, 14b and 23b were crossed with each other, and the segregation of F2 plants with spring habit as judged by flag leaf emergence under 24-hr photo period was investigated, all of the mutants were found to have a single recessive gene in common. The gene of incomplete spring habit involved in Ea 7b was also allelic to the gene of Ea 4. To identify the mutated gene, Ea 4 and Ea 7a were crossed with the tester of two dominant genes for complete spring habit, Sh₂^I and Sh₃. Segregation of spring vs. winter habit in F2 is shown in Table 2. The number of spring habit plants showed a good fit to that expected from 13:3 ratio in crosses between the mutants and Sh₂^I. But it was larger than expected in crosses involving Sh₃. The segregation of plants with winter habit in F2 suggests that the mutated gene is not allelic to Sh₂^I or Sh₃. A cross of the mutants with a tester of another gene for spring habit sh is now being made.

Table 1. Spring habit mutants of barley induced from a winter cultivar Chikurin Ibaraki 1.

Table 2. Segregation of spring vs. winter habit plants in F1 and F2 of crosses between two mutants and Sh₂^I and Sh₃ testers.

References:
Yasuo Ukai and Atsushi Yamashita. 1981. Early maturing mutants induced by ionizing radiations and chemical in barley. Barley Genetics IV: 846-854.

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