|Miklas, Phillip - Phil|
Submitted to: Bean Improvement Cooperative Annual Report
Publication Type: Research Notes
Publication Acceptance Date: 2/1/2003
Publication Date: 5/1/2003
Citation: OSORNO, J.M., BEAVER, J.S., FERWERDA, F., MIKLAS, P.N. TWO GENES FROM PHASEOLUS COCCINEUS L. CONFER RESISTANCE TO BEAN GOLDEN YELLOW MOSAIC VIRUS. BEAN IMPROVEMENT COOPERATIVE ANNUAL REPORT, 46:147-148. 2003.
Interpretive Summary: Bean golden yellow mosaic is vectored by whiteflies and has been a devastating disease of dry and snap beans grown in the tropics of Latin America, Caribbean basin and Florida. The disease causes plant stunting, deformed pods, and significant yield loss. Genetic resistance has been the only effective control strategy, and is only partially effective. There is a need to identify additional sources of resistance for the development of bean cultivars with better resistance. Scientists from the USDA-ARS and the University of Puerto Rico (Mayaguez, PR) worked together for ten years to extract resistance to bean golden yellow mosaic from Scarlet Runner bean and introgress it into dry bean via interspecific hybridization techniques. Progeny from the crosses were subjected to intensive field selection under high levels of disease pressure for six successive generations to identify and obtain highly resistant lines. The developed line USPR-VCI-6 has a high level of resistance derived from Scarlet Runner bean, which will be useful for improving resistance in dry bean and snap bean cultivars grown throughout the tropics and subtropics. Genetic studies determined that two genes one dominant and the other recessive with different modes of action, reduced pod deformation and reduced chlorosis, respectively, conditioned the resistance response.
Technical Abstract: In Central America and Caribbean, Bean Golden Yellow Mosaic (BGYM) can cause significant reductions in the yield and quality of beans. Symptoms caused by this whitefly-transmitted geminivirus include mosaic with intense foliar yellowing (chlorosis), leaf curling, pod deformation and severe plant stunting. The scarlet runner bean (Phaseolus coccineus L.) accession G35172 was identified at CIAT as a novel source of resistance to BGYM in Central America and the Caribbean. The purpose of this research was to study the inheritance and nature of BGYM resistance derived from G35172. The advanced line USPR-VCI-6 derived from the cross `HP8437-95*2/G35172', was obtained by combined pedigree and bulk selection methods for field resistance to BGYMV for six generations. HP8437-95 is a BGYM susceptible small red line from the cross 15R-148/3M-81. An F2 population was developed from the cross `Arroyo Loro//USPR-VCI-6. Arroyo Loro is susceptible to BGYMV. Each F2 plant was evaluated for the absence or presence of leaf mosaic at 30 days and for pod deformation at 55 days after planting. Phenotypic ratios from the field and greenhouse experiments suggest that one recessive gene confers resistance to leaf mosaic, and a dominant gene controls resistance to pod deformation caused by BGYM. These genes will be useful in breeding cultivars with enhanced resistance to BGYMV.