|Ruso, J - INST AG SOSTENIBLE, SPAIN|
Submitted to: Proceedings Sunflower Research Workshop
Publication Type: Proceedings
Publication Acceptance Date: February 29, 2000
Publication Date: N/A
Interpretive Summary: Adverse interactions when perennial Helianthus species cytoplasms are combined with nuclear genes from cultivated inbred line HA89 were reported. Normal plants would require vigor restoration nuclear genes to counteract the vigor-reducing perennial species cytoplasm. A lack of vigor restoration genes in cultivated lines could potentially limit the utilization of perennial species cytoplasm for sunflower breeding. This study reports the existence of nuclear vigor restoration genes in cultivated lines, and their mode of inheritance. A high frequency of vigor restoration genes was found among 14 cultivated lines after crossing them with reduced-vigor HA89 plants in perennial species cytoplasms, and the vigor restoration was under the control of single dominant genes. This discovery allows the breeders to focus on breeding effort other than looking for vigor restoration genes when utilizing perennial species cytoplasms.
Technical Abstract: Reduced-vigor plants of (H. mollis x HA89-8, vv) in 1998 were pollinated with 14 cultivated sunflower lines. Crosses with HA821, HA234, and RHA271 produced only normal progenies suggesting homozygous vigor restoration genes. Crosses with HA89, RHA801, and Seneca produced only reduced vigor progenies, indicating an absence of restoration genes in those lines. Progeny from crosses with the remaining eight lines had a high frequency of normal plants. Vigor-restored normal F1 plants were self-pollinated and F2 progeny evaluated in the greenhouse in 1999. The F2 segregation ratios of 3 normal (N) to 1 reduced-vigor (RV) in 9 of the 10 crosses confirmed the single dominant gene hypothesis for control of vigor restoration. Due to the widespread usage of H. tuberosus in breeding programs in the former USSR, and their utilization in breeding programs worldwide, it is likely that the VV genes identified in many lines originated from H. tuberosus, and therefore may be the same gene. To test this hypothesis, F2's from a half -diallel cross combination among RHA271, HA234, VNIIMK, Armavir, Issanka, and HA821 was made, and the F1's test- crossed onto RV and cytoplasmic male-sterile (cms) plants of (H. rigidus x HA895). Using the cms and RV H. rigidus x HA89-5 plants as female parents eliminated accidental selfing during emasculation and increase the accuracy our experiment.