Inheritance of Restoration of Helianthus petiolaris sp. fallax (PEF1) Cytoplasmic Male Sterility
Worldwide production of cultivated hybrid sunflower (Helianthus animus L.) presently utilizes only the PET1 source of cytoplasmic male sterility. The use of one sterile cytoplasm creates a high degree of genetic vulnerability. The objective of this study was to investigate the stability of a new cytoplasmic male sterile source, PEF1, derived from Helianthus petiolaris sp. fallax Heiser and to determine the inheritance of restoration of this cytoplasm. Crosses were made between the PEF1 cytoplasmic male sterile source and several restorer lines known to restore the PET1 cytoplasm. None of the PET1 restorer lines had effective restoration genes for the PEF1 cytoplasm. Two genotypes, ‘Zaria’ (PI 371935) and HA 60 (Ames 4035), restored male fertility to the PEF1 cytoplasm. Fully fertile F5 plants obtained from these crosses were used to pollinate the PEF1 cytoplasm. The fertile F1 plants were self-pollinated and backcrossed to the PEF1 source to obtain F2 and BC1F1 seeds, respectively. These generations were planted in the field nursery at Fargo, ND, in 1994. Data were recorded for pollen restoration. The restoration of the PEF1 cytoplasmic male sterile was determined to be controlled by two complementary dominant genes with cumulative gene action. The stability and effective restoration of the PEF1 cytoplasm indicated that this source could be utilized to decrease the genetic vulnerability in hybrid sunflower.
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