ARS | Publication request: QTL may explain a tolerance response to Pea enation mosaic virus in pea

Submitted to: Food Legume Research International Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: February 10, 2010
Publication Date: April 10, 2010
Citation: Larsen, R.C., Porter, L., Mcphee, K. 2010. QTL may explain a tolerance response to Pea enation mosaic virus in pea. Proc. Int. Food Legume Res. Conf. 7:326.

Technical Abstract: Pea enation mosaic virus (PEMV) is a serious disease of fresh market and dry pea in the Pacific Northwest region of the U.S. The dominant En gene confers resistance to PEMV in pea, however, only a limited number of available cultivars contain the gene. While some cultivars have been reported with partial resistance to PEMV, no sources of true tolerance to the virus have been reported. The objective of our research was to identify potential sources of tolerance in pea germplasm and breeding lines that will be useful in development of commercial lines that do not possess the dominant En gene. A set of advanced pea breeding lines was screened for resistance to PEMV in naturally infected field trials in Corvalis, OR. Four advanced breeding lines that were symptomless in field trials exhibited typical foliar and pod symptoms caused by PEMV infection when evaluated under greenhouse screening conditions, but plant growth was not significantly different than the buffer-treated controls. The lines demonstrated tolerance to PEMV since pod-fill and seed size was not significantly different than the controls. RT-PCR primers specific to the coat protein gene of PEMV were used to assess symptomatic tissue from inoculated plants. Virus titer was not different from susceptible controls in lines PS08-39, PS08-68 and PS08-76 but was significantly less in most individuals from line PS08-41. Virus titer was consistently low in progeny of low-titer PS08-41individuals and consistently high from high-titer individuals. Quantitative trait loci may explain the tolerance response to PEMV in breeding lines PS08-39, PS08-41, PS08-68 and PS08-76.