Processors and Growers Research Organisation

Pea Downy Mildew diversity in the UK

Project summary:

The project aims to provide growers with information about Downy Mildew race structure, geographic spread in the UK and varietal tolerance to races. Pea DM is a major disease of both vining and combining peas in the UK and current conventional control options are limited to a seed treatment, rotational management and varietal tolerance. Varietal tolerance, however, may vary in different regions as race structure of DM changes. Little is known about race structure and the investigation will identify races in the UK and map their distribution to allow growers to utilise varietal information to greater benefit. Information from the project will be fed back into the breeding industry to develop improved resistance in pea varieties.

Benefits to industry:

Currently DM in peas is controlled through crop rotation (one year in five) and use of disease tolerant varieties in areas of high disease pressure. However there are reports that some varieties do not perform well in all pea growing areas due to the presence of different races of DM. The project aims to investigate pea DM population diversity in the UK and produce a map to illustrate relative occurrence of races and to support the later genetic studies. Current commercial varieties will be tested for susceptibility to the races of the disease to inform growers of varietal tolerance in specific areas. The information will be provided to growers via the PGRO website, PGRO Growers Guide and at open days and events to aid regional varietal selections. Improved knowledge of varietal selection will help to reduce the reliance on seed treatments.

Findings will also be passed on to pea breeders to aid in their selection and breeding programmes. The long-term benefit of the study will become available to growers in the development of varieties with improved disease tolerance.

Sector: Horticulture
Project code: FV 436
Date: 01 April 2014 - 31 March 2018
Funders: AHDB Horticulture
AHDB sector cost: £196,432
Project leader: DR KERRY MAGUIRE, PGRO










About this project
Aims and objectives:

To investigate the race diversity of Pea Downy Mildew (DM) in the UK and the impact this has on plant susceptibility.
To produce a map with race distribution across the main pea growing areas

Project objective(s):
a. To carry out a desk study to review current literature on genetic stock and downy mildew race interactions
b. To collect pea material infected with downy mildew from pea production areas in the UK.
c. To type the isolates into races using the differentials defined by JIC
d. To assess varietal and exotic germplasm susceptibility to the different isolates
e. To understand the utility of genetic markers for resistance in breeding programmes
f. To generate a map illustrating the location of the races across the main pea growing areas of the UK
g. To identify the location of the different races and to compare the changes over the four years
h. To disseminate findings to growers and breeders