2011 Annual Report
1a.Objectives (from AD-416)
Our objective is to develop landmark cultivars, advanced breeding lines and information for use by other breeders, scientists, producers and growers. This research will emphasize developing resistance to diseases, insects, and physiological defects, as well as the development of molecular markers for genetic analysis and marker assited selection.
1b.Approach (from AD-416)
Problems facing the lettuce industry will be addressed using genetic approaches in field, greenhouse, and laboratory experiments that are suited to coastal, desert, and interior valley locations, to the various types of lettuce, and to the demands of different production and marketing approaches.
This project is monitored through twice yearly written and oral reports. Our objectives are to incorporate resistance to several diseases, insects, and physiological defects into iceberg, romaine, and mixed lettuce cultivars and breeding lines adapted for coastal and low desert production. In the 2010-2011 period, major efforts targeted resistance to lettuce big vein disease, lettuce drop caused by Sclerotinia species, Verticillium wilt, Fusarium root rot, lettuce dieback/tombusviruses, bacterial leaf spot, corky root, downy mildew, leafminer, lettuce aphid, tipburn, shelf-life of salad-cut lettuce, and multiple disease resistance. Minor programs addressed resistance to yellow spot. In all programs, horticultural traits, adaptation, and resistance to tipburn are essential. We confirmed resistance in previously identified germplasm to Lettuce Drop, Verticillium wilt, Fusarium wilt, Yellow Spot, dieback, and lettuce aphid. Selections were taken from breeding populations and advanced breeding lines were evaluated as part of breeding for resistance to big vein disease, lettuce drop, Verticillium wilt, dieback, bacterial leaf spot, corky root, leafminer, tipburn, and pre-mature bolting. Genetic studies concurrent with breeding programs are being conducted to determine the inheritance of resistance to big vein disease, bacterial leaf spot, dieback, leafminers, downy mildew, lettuce aphid, corky root, shelf-life of salad-cut lettuce and Verticillium wilt.