| Discussion Most F5 plants had complete or nearly complete male sterility and had a ring-of-four or a chain-of-four at metaphase 1 of meiosis in some of the pollen mother cells. Of the 34 F5 plants, one had 2n=37 (15II1III4I) and another had 2n=42 (18II1V1I). These plants would produce complex aneuploids. If the genetic male sterile stocks reported by other workers have structural heterozygosity, then those male sterile stocks may show cytological instability. WANINGE and ZEVEN reported PUGSLEY'S genetic malesterile had aneuploids. Our male-sterile wheat plants had chromosome-structural heterozygosity and some of these produced aneuploids or plants with one or two multivalents of three, four, five or six chromosomes. Apparently, selection for male sterility resulted in selection for chromosomal interchanges. Because frequency of a multivalent between plants was different, all male-sterile plants may not have an identical chromosome interchange. Literature cited 1. ATHWAL, D. S., P. S. PHUL and J. L. MINOCHA 1967. Genetic male sterility in wheat. Euphytica 16: 354-360. 2. BRIGGLE, L. W. 1968. Genetic male sterility in hexaploid wheat. Proc. 11th Hard Red Winter and Hard Red Spring Wheat Workers Conference. Feb. 6-8, 1968, p. 100-101. 3. GILL, B. S. and S. C. ANAND 1970. Genetic male sterility for hybrid seed production in wheat. Crop Science 10: 385-386. 4. PUGSLEY, A. T. and R. N. ORAM 1959. Genetic male sterility in wheat. Australian Plant Breeding and Genetics Newsletter 14. 5. WANINGE, J. and A. C. ZEVEN 1968. Chromosome numbers in Pugsley's male sterile wheat. Euphytica 17: 378-380. (Received October 30, 1970) |
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