|SANDOYA, GERMAN - University Of Florida|
|TRUCO, MARIA-JOSE - University Of California|
|SUBBARAO, KRISHNA - University Of California|
|MICHELMORE, RICHARD - University Of California|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 6/30/2017
Publication Date: 8/10/2017
Citation: Sandoya, G.V., Truco, M.J., Subbarao, K.V., Martin, F.N., Michelmore, R.M., Hayes, R.J., Simko, I. 2017. Breeding and genetics of lettuce for resistance against race 2 Verticillium wilt. National Association of Plant Breeders Annual Meeting, August 7-10, 2017, Davis, California.
Technical Abstract: Verticillium wilt, caused by Verticillium dahliae Kleb., is an economically important disease of lettuce in central coastal California. Most isolates of the pathogen detected in the Salinas Valley belong to race 1 for which complete resistance exists. However, adequate level of resistance is not available against race 2 that is present in low frequency but may potentially spread throughout the main production areas. We screened over 1,200 Lactuca sativa and L. serriola accessions from the U.S. National Germplasm System for their reaction to race 2 of V. dahliae. Partial resistance to race 2 was identified in L. sativa accessions PI 171674, PI 204707, and L. serriola 11G99. Analyses of three bi-parental mapping populations developed by mating these accessions with partial resistance revealed quantitative trait loci (QTL) for resistance on several linkage groups (LG). A common QTL was detected on LG6. Spectral analysis of accessions with resistance to race 1 (e.g., cv. La Brillante) and the susceptible check cv. Salinas were performed to quantitafy wilting following infection with race 2. No significant differences were observed between the inoculated plants and controls, with only a minor difference at wavelengths related to chlorophyll absorption. Limited differences between infected and healthy plants were detected using the chlorophyll fluorescence approach in preliminary investigations. Accessions with the highest partial resistance to race 2 were incorporated into our breeding program for introgression of resistance into breeding lines.