Mitochondrial DNA RFLP and genetical studies of cytoplasmic male sterility in the sunflower (Helianthus annuus).

Fifteen sunflower (Helianthus annuus L.) cytoplasmic male-sterile, and a single male-fertile, cytotypes were studied by both mtDNA (mitochondrial DNA) restriction fragment length polymorphism (RFLP) and genetical analysis of male-fertility restoration patterns. It was found by multivariate analysis that the two methods of identification of cytoplasmic male sterility (CMS) should be of use in sunflower breeding programs. The RFLP study distinguished 13 groups based on differences in mtDNA organization. DNA molecular diversity occurs both within and between the Helianthus species from which the steriles originate. The mitochondrial genes analyzed present specific molecular configurations for each type of sterility studied. The analysis of male-fertility restoration separated the cytotypes into 12 groups. The associations of CMS and inbred restorer lines indicated the presence of specific nuclear genes involved in cytoplasmic male-sterility restoration.