|Ruso, Juan - CSIC, CORDOBA, SPAIN|
Submitted to: National Sunflower Research Forum 2001 Proceedings
Publication Type: Proceedings
Publication Acceptance Date: March 18, 2002
Publication Date: N/A
Interpretive Summary: Adverse cytoplasmic-nuclear interactions were reported when perennial Helianthus species cytoplasms are combined with nuclear genes from cultivated inbred line HA89. Normal plants would require vigor restoration nuclear genes to counteract the vigor-reducing perennial species cytoplasm. Sufficient vigor restoration genes exist in cultivated lines which provide opportunity toward the utilization of perennial species cytoplasm for sunflower breeding. This study reports the existence of nuclear vigor restoration genes in cultivated lines, and their relationship. A high frequency of vigor restoration genes was found among14 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: A half diallel cross combination was made among HA271, HA234, VNIIMK, Armavir, Issanka, and HA821, all homozygous for a vigor restoration gene. Testcrosses were made by pollinating the 15 F1s onto the vigor-reduced cmsRIGX plants in HA89 background. In the second test, the 11 cultivated lines homogenous or with high frequency of vigor restoration genes in our previous report were emasculated and pollinated with HA89 (vv) pollen. The all normal F1s were grown in the greenhouse, and the F2 progenies were evaluated for segregation of normal and reduced-vigor plants. The F1 and the testcross progenies of the half-diallel crosses among the six cultivated lines indicated that all the six lines possess the same VV gene which was likely derived from H. tuberosus by early sunflower breeders in the former Soviet Union. Progenies of the 11 lines, HA271, HA234, VNIIMK, Armavir, Issanka, HA821, RHA296, Peredovik, Smena, P21-VR1, Issanka, and Hopi Dye crossed with HA89 were all normal, suggesting the absence of perennial species cytoplasms in those lines. The high frequency of VV gene in lines without obvious selective advantage was unclear. It is likely that the VV gene is tightly linked with genes controlling desirable agronomical traits and was simultaneously selected and maintained in those lines. In addition, because of the abundance of VV genes in cultivated germplasm lines, utilization of perennial species cytoplasms in sunflower breeding should not be especially difficult.