Tests for a cytoplasm that restores genetic male sterile-1

Z. diploperennis cytoplasm does not restore ms1. Plants from diploperennis female x +/ms were selfed and also crossed on ms. Testcross progenies that segregated for male sterility came from plants whose self progeny also segregated for male sterility. This does not rule out the possibility that diploperennis cytoplasm might restore one of the other genetic male steriles.

Last year's report, made before plans for 1983 were completed, stated that the A188 and T6-9b "standard normal" lines did not have a restorer cytoplasm for ms1. That may not be correct. Additional self progenies from both lines crossed with +/ms had no male sterile progeny. Plants in those progenies were again selfed and testcrossed on ms1. For the A188 line, the fertile plants in two progenies from A188 x (ms/T2-6) were selfed and testcrossed on ms. The test crosses now growing in Hawaii that segregate for male sterility will identify plants whose self progeny will be tested here in 1984, completing the test for the cytoplasms of the two lines. Note: T2-6 is closely linked to ms. Hence fertile plants from crosses with them should be +/ms heterozygotes.

C. R. Burnham

Please Note: Notes submitted to the Maize Genetics Cooperation Newsletter may be cited only with consent of the authors.

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