A genomics based approach to managing downy mildew of lima bean

Abstract

Lima bean is the cornerstone of the vegetable processing industry in the Mid-Atlantic region (MAR). An overall nationwide decline in lima bean production has allowed the MAR to occupy this niche market area and increase its production and revenue. However, Phytophthora phaseoli, the causal agent of downy mildew remains a scourge for lima bean producers, causing significant periodic losses. New races of P. phaseoli have worsened the situation for farmers, rendering resistant cultivars susceptible and increasing their chemical input costs as they attempt to limit yield losses. This dissertation seeks to address this issue through two main objectives: first, through the development of genetic resources that will enable more targeted breeding for crop resistance to P. phaseoli and second, by examining the phenotypes and the population structure of the pathogen in grower fields. The latter objective provides a better understanding of the pathogens resistance to mefenoxam and its clonal structure. The overall goal of this work is to provide a pathway to more efficient disease control strategies through a better understanding of the pathogen and the host, leading to improved lima bean production in the MAR.