MITOCHONDRIAL-DNA RFLP AND GENETIC-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 (mitochon drial DNA) restriction fragment length polymorphism (RFLP) and genetic al analysis of male-fertility restoration patterns. It was found by mu ltivariate analysis that the two methods of identification of cytoplas mic male sterility (CMS) should be of use in sunflower breeding progra ms. The RFLP study distinguished 13 groups based on differences in mtD NA organization. DNA molecular diversity occurs both within and betwee n the Helianthus species from which the steriles originate. The mitoch ondrial genes analyzed present specific molecular configurations for e ach type of sterility studied. The analysis of male-fertility restorat ion separated the cytotypes into 12 groups. The associations of CMS an d inbred restorer lines indicated the presence of specific nuclear gen es involved in cytoplasmic male-sterility restoration.