Inheritance of resistance to early blight disease in a diploid potato population

Abstract

AbstractEarly blight disease, caused by Alternaria solani Sorauer, is a serious disease of potato foliage and tubers that occurs in most potato‐growing regions world‐wide. Developing new potato cultivars with resistance to early blight may reduce losses in the field and in storage, and lessen the need for fungicide applications. A total of 280 clones, derived from 72 maternal half‐sib families from a diploid random‐mated hybrid population of Solarium phureja×Solarium stenotomum were examined for resistance to early blight. The clones that were evaluated in a replicated field trial for 2 years in Pennsylvania, USA, had similar early blight intensity both years. Significant differences were found among families, within families and for the interaction of years × within families. Broad‐sense heritability for resistance, measured as area under the disease progress curve (AUDPC), was estimated as 0.73, with a 95% confidence interval of 0.65‐0.78, and narrow‐sense heritability was estimated as 0.61 ± 0.29 (P = 0.05). The correlation of AUDPC for early blight between years was 0.57 (P < 0.0001). These results suggest that this diploid population is worthy of use in breeding for early blight resistance.