Genetic Analyses of Male-Fertility Restoration in Wheat. I. Chromosomal Location of Rf Genes1
- S. S. Maan,
- K. A. Luchen and
- J. M. Bravo2
A monosomic set of Triticum aestivum L. ‘Chris’ was used to determine the chromosomal location of male-fertility restorer (Rf) genes in R113, a T. aestivum R-line with T. timopheevii Zhuk. cytoplasm. Cytologically identified monosomic F1s (Chris monosomic × RII3) were crossed as males to cytoplasmic malesterile Chris with T. timopheevii cytoplasm. The testcross F1 progenies were grown in the greenhouse in 1981 and 1982. Seed set data obtained from bagged spikes of plants within each of the 21 segregating populations w~ere used to identify progenies with Rf genes. Rl13 had Rf genes on chromosomes 1A and 6B. The gene on 6B had higher penetrance than the gene on 1A, and the gene on 1A had higher expressivity than the gene on 6B. Also, Rf genes of low penetrance or modifier genes were located on chromosomes 1B, 4B, and 4D, and inhibitors of male fertility were located on 5A, 6A, and 5B; their expression was influenced by environment. In gelaeral, the effect of Rf genes on 1A and 6B was not large enough to influence mean seed sets of fertile plants within their respective families relative to the mean seed sets of fertile plants within the non-critical families. Results from testcross F1-derived F2 progenies further indicated that genes on chromosomes 7B, 1D, 4D, 5D, and 7D apparently had a positive effect on fertility restoration when they were homozygous but not when they were heterozygous. Therefore, the high fertility restoration potential of hybrids involving Rl13 may result from the balanced, cumulative effects of the Rf genes and their modifiers located on several chromosomes of the A, B, and D-genomes of wheat.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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