Grape Breeding for powdery mildew resistance

Abstract

Powdery mildew is one of the most common fungal diseases that cause severe damage to grapes. Grape growers spend lot of money for chemical control of this disease, which eventually increases the cost of cultivation. Use of grape varieties resistant to powdery mildew in grape cultivation is cost-effective as well as environmentally friendly. Hence breeding varieties for disease resistance is an important objective of any grape improvement programme. A wild species of grapes Vitis rotundifolia, being a good source of resistance to powdery mildew is a natural choice in grape breeding programs all over the world. In the present study, 136 hybrids were developed from a cross of V. rotundifolia cv James as a female parent with 6 commercial varieties (Beauty seedless, Gulabi, Sharad seedless, Kali Sahebi, Kishmish Beli and Tas-A-Ganesh) grown in India. They were screened for powdery mildew in epiphytotic conditions in 2014-15 and 2015-16. Out of these hybrids evaluated, eleven hybrids were selected on the basis of powdery mildew disease resistance as well as quality traits. Seven hybrids were rated as resistant and 5 hybrids as moderately resistant on the basis of the severity index. Of these three hybrids identified from a cross of James and Kishmish Beli (H-1301, H-1302, H-1308) showed resistance along with desirable fruit quality characters. These hybrids are being further tested for commercial use and can further be used as genetic resistance source for management of the disease in national grape improvement program.