Impact of Environmental Variables on Reaction of Canola Germplasm to Inoculation with Sclerotinia sclerotiorum
Luis del Rio, North Dakota State University - $4,491

Sclerotinia stem rot of canola (SSR) caused by the fungus Sclerotinia sclerotiorum, is a yield-limiting disease considered to be endemic in North Dakota. Currently, this disease is managed mainly though fungicide applications and crop rotation practices. Genetic resistance to this pathogen is polygenic. Screening methodologies developed to discriminate between susceptible and resistant materials under greenhouse conditions have, in many instances, produced results that are not consistent with field inoculations.

This lack of consistency has been attributed to a number of factors, among them environmental conditions like temperature and light. Temperature and light quality in greenhouse rooms can vary with daily conditions and with the season. Heat is a detriment during the summer and early fall, and the number of daylight hours and the quality of light can vary significantly between early fall and winter.

As a result, screening procedures not only may produce inconsistent results, but in order to retain as much consistency as possible, they can only be conducted in a short period of time every year. In order to make the screening efforts more effective, and to be able to evaluate larger number of accessions in shorter periods of time, screening activities need to be conducted under more controlled conditions.

The National Genetic Resources Program (NGPR) keeps more than 1,000 accessions of two canola species (B. napus and B. rapa), at its repository center in Ames, IA. These collections are an untapped potential source for sources of resistance to S. sclerotiorum. The screening of these species could be sped up greatly and the efficiency of selection enhanced significantly if the screening is conducted under growth chamber conditions.

Objective:
1. Study the impact of temperature and light quality on the response of canola germplasm to inoculation with Sclerotinia sclerotiorum.