|BODAH, ELIANE - WASHINGTON STATE UNIVERSITY|
|CHAVES-CORDOBA, BERNARDO - WASHINGTON STATE UNIVERSITY|
|DHINGRA, AMIT - WASHINGTON STATE UNIVERSITY|
Submitted to: Euphytica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/21/2015
Publication Date: 1/27/2016
Citation: Bodah, E., Porter, L., Chaves-Cordoba, B., Dhingra, A. 2016. Evaluation of pea accessions and commercial cultivars for Fusarium Root Rot resistance. Euphytica. 208:63-72. doi: 10.1007/s10681-015-1545-6.
Interpretive Summary: Fusarium root rot caused by Fusarium solani f. sp. pisi (Fsp) can cause major yield losses in pea. Currently, fungicides are not effective in managing this disease, and the expense of applying fungicides is often cost-prohibitive in dryland growing regions, even if fungicides were available. The most efficient, cost-effective and environmentally friendly approach to managing Fsp is through genetic host resistance to the pathogen. Genetic resistance to Fsp of current US commercial cultivars of different pea market classes has never been determined, making it difficult for growers to select cultivars to grow in problem areas. In addition, breeders need to know which commercial pea cultivars of different market classes have the best resistance to Fsp to incorporate this resistance into future breeding efforts. Lastly, breeders need to determine how variable levels of susceptibility (0 to 6 scale, with 6 being the most susceptible) to Fsp impacts the growth (height, root weight, shoot weight) of pea lines. The present research identified that the most Fsp-resistant Austrian winter, green fresh, green dry, yellow dry, green winter and yellow winter pea were: PI 125673, 00-5003, ‘Banner’, ‘Carneval’, PS 05300234, and ‘Whistler’, respectively. These pea lines, within these market classes, can be used by growers in regions where Fsp is problematic and used by breeders as parents to improve genetic resistance to Fsp within these market classes, while preserving valuable horticultural characteristics. It was determined that a pea line demonstrating a root disease severity value of 3.05 or less tended to have normal height, root and shoot growth compared to non-infected plants of the same line. Disease severity values of 3.05 or less should be targeted by breeders selecting for Fsp resistance to minimize the impact of Fsp on future pea production.
Technical Abstract: Fusarium root rot caused by Fusarium solani f. sp. pisi (Fsp) can result in major yield losses in pea (Pisum sativum L.). Currently no fungicides effectively manage this disease. Previous studies evaluated the Pisum germplasm collection for resistance to Fsp, however, evaluations of commercial market classes of pea cultivars grown in the US, and elsewhere, have not been reported. This study evaluated pea accessions and commercial cultivars for Fsp resistance under greenhouse conditions. Based on root disease severity (RDS) values, the most Fsp-resistant Austrian winter, green fresh, green dry, yellow dry, green winter and yellow winter pea were: PI 125673, 5003, ‘Banner’, ‘Carneval’, PS 05300234, and ‘Whistler’, respectively. Genotypes with a RDS value of 3.05, on a 0 to 6 scale with 6 being severe, or less had no significant (P = 0.05) reductions in plant height, shoot dry weight, and root dry weight, compared to non-inoculated controls, establishing an important disease threshold value for pea breeders. Plant height, more than shoot dry weight or root dry weight, was the most highly negatively correlated growth parameter related to RDS in repeated tests based on Pearson’s Correlation coefficients. However, root dry weight was the most sensitive parameter affected by Fsp since 14 of 33 genotypes had significant (P = 0.05) reductions in root dry weight compared to non-inoculated controls, while only 5 of 33 genotypes had significant reductions in plant height or shoot dry weight in one or more tests.