Screening of potato genotypes against Phytophthora infestans causing late blight of potato under subtropical plains of India

Abstract

The late blight disease caused by Phytophthora infestans, is a serious concern to potato cultivation in the world. The varietal resistance is cheapest and environment- friendly option to manage this disease. A total of twenty eight (11 exotic and 17 indigenous) advanced potato hybrids along with nine control varieties namely Kufri Bahar, Kufri Badshah, Kufri Girdhari, Kufri Jyoti, Kufri Pukhraj (white skin) Kufri Arun, Kufri Lalima, Kufri Lalit, Kufri Sindhuri (red skin) were evaluated during two consecutive crop seasons (2015-16 & 2016-17) for resistance against late blight disease. Based on field evaluation (AUDPC values) exotic advanced hybrids CP4401 (11.62), CP4386 (32.49) and CP4403 (55.84) were graded highly resistant. Two indigenous advanced hybrids i.e. MCIP/12-185 and MS/12-935 were resistant and six advanced hybrids were moderately resistant, while remaining 17 advanced hybrids (AUDPC>375) were susceptible against cv. Kufri Bahar (AUDPC-1002.26). The mean rAUDPC values of evaluated advanced stage hybrids, ranged from 0.01 to 0.35 as against highly susceptible cv. Kufri Bahar (0.48). In laboratory detached leaf test, advanced hybrid CP4386 was highly resistant, whereas two advanced hybrids i.e. CP4403 & MCIP/12-185 were resistant and eight were moderately resistant remaining 17 were susceptible for foliar blight while fifteen advanced hybrids were moderately resistant and remaining were susceptible as ascertained through tuber slice method. Foliage resistance, tested under laboratory condition using detached leaf test and field condition did not establish close relationship. The expression of late blight in foliage and tuber were not closely related.