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Title: Usefulness of Molecular Markers to Screen for PVY Resistance (Ryadg gene) in Potatoes

item HANE, D
item Brown, Charles - Chuck
item YILMA, S
item MOSLEY, A
item VALES, M

Submitted to: American Journal of Potato Research
Publication Type: Abstract Only
Publication Acceptance Date: 3/15/2006
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Potato yield, quality and tuber seed production are seriously limited by Potato virus Y (PVY Potyvirus). Artificial inoculation under controlled conditions followed by DAS-ELISA is commonly used to screen for PVY resistance, but this method is very tedious and time consuming prohibiting the screening of large segregating populations. Efforts have been made to identify and genetically map resistance to PVY. The gene Ryadg from S. tuberosum ssp. andigena provides extreme resistance to PVY. This gene was mapped to chromosome XI and user-friendly PCR-based DNA markers linked to the gene have been developed. The objective of this work is to assess the usefulness of molecular markers for determining the allelic configuration at the Ryadg gene and as an early selection tool for predicting PVY resistance. To achieve this, an F1 population segregating for Ryadg was screened with molecular markers and also inoculated artificially with PVY and tested by DAS-ELISA. Ninety-six percent of the segregating lines showed coincidence between the molecular markers and DAS-ELISA results. Discrepancy in the remaining 4% could be due to escapes from inoculation, errors in ELISA or PCR assays or recombination between the markers and the Ryadg gene. Results of ELISA screening fit a 1:1 (resistant:susceptible) segregation ratio indicating the presence of Ryadg as a simplex. The same segregation ratio was confirmed by using molecular markers. Our results indicate that molecular markers can be used as a fast and convenient tool to determine the allelic composition of resistant parental lines at the Ryadg locus. This information could be used to determine the number of field selections necessary to maintain PVY resistance. Clones selected at early generations (mainly based on tuber type and shape) can be quickly screened with molecular markers to predict resistance to PVY. Resistance predictions can subsequently be confirmed by other methods.