Inheritance and Allelism of Mitomycin C- and Streptomycin-Induced Recessive Genes for Male Sterility in Cultivated Sunflower
Nuclear male sterility (NMS) conditioned by recessive genes provides a useful tool for sunflower (Helianthus annuus L.) breeding and genetics programs. The objectives of this study were to evaluate seven induced NMS mutants derived from inbred line HA 89 and two lines, B11A3 and P21, for their mode of inheritance, allelic relationships, and agronomic characteristics. Self-pollinated F2 progenies from heterozygous F1 male-fertile (MF) plants and BC1F1 progenies from crossing male-sterile (MS) with F1 heterozygous MF plants segregated in ratios of three MF to one MS and one MF to one MS, respectively, indicating single recessive gene control of male sterility. Half-diallel crosses of MS with heterozygous F, MF plants indicated that the seven NMS mutant lines represented mutations at four loci that differ from that of P21 or B11A3. Male-fertile segregates had normal pollen production, as that of HA 89, and MS segregates lacked anther extrusion and pollen production in both field and greenhouse evaluations. B11A3 had a few partially fertile florets at the center of the heads in summer greenhouse plantings, perhaps due to high temperature. The shorter plant height and associated female sterility in NMS 747 (ms8) make it less useful. B11A3 (mslO) and P21 (msll) are agronomically less desirable because of their taller height and lower self-compatibility. NMS 360 (ms9), 552 (ms7), and 872 (ms6), representing three of the four mutant genes, performed similarly to agronomically adapted HA 89, were completely male-sterile, and should be considered for use in future genetics and breeding programs as replacements for B11A3 and P21.
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