IMPROVED KNOWLEDGE OF VIRULENCE FACTORS TO DEVELOP POSTHARVEST DECAY CONTROL STRATEGIES
Title: Identification of wild apple germplasm (Malus spp.) with resistance to the postharvest decay pathogens Penicillium expansum and Colletotrichum acutatum
Submitted to: Plant Breeding
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 21, 2010
Publication Date: August 1, 2011
Citation: Jurick Ii, W.M., Janisiewicz, W.J., Saftner, R.A., Vico, I., Gaskins, V.L., Park, E., Forsline, P.L., Fazio, G., Conway, W.S. 2011. Identification of wild apple germplasm (Malus spp.) with resistance to the postharvest decay pathogens Penicillium expansum and Colletotrichum acutatum. Plant Breeding. 130:481-486.
Interpretive Summary: Blue mold and bitter rot of apple fruit is caused by two different fungi. They are among the most economically important disease of apples, which cause significant losses in storage, and are mainly controlled by the use of fungicides. However, consumers desire alternatives to controlling this disease without using chemicals. No resistance occurs in apple fruit to either of these fungi. Therefore, we have screened wild apples for resistance to both bitter rot and blue mold. Our data show for the first time that resistance occurs in select wild apple trees against both pathogens and may be used as a source of resistance in commercial apple cultivars. Many different audiences will benefit from this information such as growers, packers, plant breeders, plant pathologists and consumers.
Penicillium expansum and Colletotrichum acutatum cause blue mold and bitter rot of apples during storage which results in significant economic losses. Resistance to these pathogens in commercial apple cultivars has not been documented in the literature. An apple germplasm collection, from the center of origin in Kazakhstan, is maintained in Geneva, New York. This collection represents a more diverse apple gene pool than commercial cultivars which was evaluated for resistance to blue mold and bitter rot. Resistance reactions were skewed toward susceptibility for both fungi and comprised the majority of accessions examined. However, resistance to P. expansum was confirmed in select accessions over multiple years. Maturation patterns and quality indices for soluble solids and acidity, which also may affect pathogenicity, were highly variable and represent the genetic diversity of the germplasm collection. Resistance in four accessions to C. acutatum and two accessions resistant to both P. expansum and C. acutatum, are reported here for the first time. Data from this study will serve as a foundation for conventional apple breeding programs and molecular genetics investigations to provide resistance against blue mold and bitter rot in commercial apple varieties.