2019 ASHS Annual Conference

Pomegranate, an emerging crop in the Southeast U.S., is plagued by anthracnose leaf spot disease caused by Colletotrichum species. Identifying pomegranate varieties with resistance to anthracnose leaf spot is needed for integrated management of this disease. This study was conducted to define proper conditions for detached leaf assays and identify anthracnose leaf spot-resistant pomegranate varieties. Results indicated that pomegranate leaf age at the 4^thpair, inoculum at 10⁶conidia/mL, incubation temperature at 25°C, and 0-6 hours of light during incubation were favorable for disease development on detached leaves. Out of 17 pomegranate varieties screened using the detached leaf assay and a whole plant inoculation assay, ‘Bhagwa’ was consistently highly susceptible to the disease whereas ‘Parfyanka’ showed a moderate level of resistance. ConidiaofColletotrichum gloeosporioides inoculated onto‘Bhagwa’ and ‘Parfyanka’ leavesdid not showsignificant differences in germination and appressorium formation; however, theconidiainoculatedon‘Bhagwa’ leaves had a lower percentage of infection peg formation and produced more new conidia than on ‘Parfyanka’ leaves. These results indicate that pomegranate varieties differ in susceptibility to anthracnose leaf spot. The identified resistant variety may be useful as a tool for managing anthracnose leaf spot disease and as a breeding parent for developing new resistant pomegranate varieties.