|Pascual, Aida -|
|Campa, Ana -|
|Pérez-Vega, Elena -|
|Giraldez, Ramón -|
|Ferreira, Juan José -|
Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 13, 2010
Publication Date: July 1, 2010
Citation: Pascual, A., Campa, A., Pérez-Vega, E., Giraldez, R., Miklas, P.N., Ferreira, J. 2010. Screening common bean for resistance to four Sclerotinia sclerotiorum isolates collected in northern Spain. Plant Disease. 94: 885-890. Interpretive Summary: Common bean is the most important edible legume in the world representing 50% of all grain legume consumption. White mold is a serious disease of common bean which limits production in temperate climates worldwide. Sources of genetic resistance to this disease are rare so our goal was to find new sources of resistance. Eighteen new sources of resistance were found in a pool of 228 accessions primarily from Spain. These 18 new sources will be further characterized for resistance to white mold in the U.S. and elsewhere. Promising lines with high levels of resistance and agronomic adaptation will be used by breeders to develop dry bean cultivars with improved resistance to white mold. This disease alone results in ~$28 million lost revenue for bean growers in the U.S. on an annual basis.
Technical Abstract: White mold, caused by the fungus Sclerotinia sclerotiorum (Lib.) de Bary, is a serious disease in common bean (Phaseolus vulgaris L.) causing significant yield loss. Few cultivars with high levels of physiological resistance to white mold have been described in common bean. The objectives of this study were to: (i) determine variation in aggressiveness for the local S. sclerotiorum isolates, and (ii) identify sources of resistance against local isolates using the greenhouse straw test. The evaluated materials included 199 accessions of a core collection established from the main bean genebank in Spain and 29 known cultivars or lines, five of them described as resistant sources to white mold: G122, PC50, A195, Cornell 606 and, MO162. Significant differences for aggressiveness among the four S. sclerotiorum isolates were detected. Generally, isolates 1 and 3 were more aggressive than isolate 4. Eighteen new sources of putative resistance to white mold were found; 11 accessions from the core collection and 7 cultivars or lines from known materials. To confirm resistance, the 18 select genotypes were tested using a more severe straw test with reactions evaluated 21 days after inoculation. All 18 genotypes exhibited less disease than the resistant check G122. The logical next step will be to evaluate the 18 genotypes for field reaction to white mold and conduct inheritance studies.