Author
Submitted to: Extension Reports
Publication Type: Other Publication Acceptance Date: 6/5/2017 Publication Date: 7/27/2017 Citation: Simko, I., Mou, B., McCreight, J.D. 2017. Lettuce breeding. California Leafy Greens Research Board. Available: http://calgreens.org/wp-content/uploads/2016/06/Lettuce-Breeding-USDA-ARS-Simko-Mou-and-McCreight.pdf. Interpretive Summary: In the 2016-2017 period, major efforts targeted resistance to lettuce drop caused by Sclerotinia species, Verticillium wilt, Fusarium wilt, bacterial leaf spot, corky root, downy mildew, drought tolerance, lettuce aphid, tipburn, shelf-life of salad-cut lettuce, and multiple disease resistance. Resistance to tipburn is essential for most production areas. Selections from breeding populations and advanced breeding lines were evaluated for resistance to big vein disease, downy mildew, lettuce drop, Verticillium wilt, dieback, bacterial leaf spot, corky root, leafminer, tipburn, and pre-mature bolting. Fusarium wilt and lettuce aphid-resistant selections were advanced through selfing and backcrossing. A Fusarium wilt-resistant selection was crossed with an advanced Verticullium wilt-resistant selection as the initial step to combine resistances to these two destructive soilborne diseases. Genetic studies concurrent with breeding programs are being conducted to determine the inheritance of resistance to bacterial leaf spot, downy mildew, shelf-life of salad-cut lettuce, and Verticillium wilt. Publications during 2015-2017 included reports of original research on downy mildew, Verticillium wilt, bacterial leaf spot, shelf-life, thermotolerance, nutritional quality, marker-assisted selection, and development of molecular markers. Technical Abstract: In the 2016-2017 period, major efforts targeted resistance to lettuce drop caused by Sclerotinia species, Verticillium wilt, Fusarium wilt, bacterial leaf spot, corky root, downy mildew, drought tolerance, lettuce aphid, tipburn, shelf-life of salad-cut lettuce, and multiple disease resistance. Resistance to tipburn is essential for most production areas. Selections from breeding populations and advanced breeding lines were evaluated for resistance to big vein disease, downy mildew, lettuce drop, Verticillium wilt, dieback, bacterial leaf spot, corky root, leafminer, tipburn, and pre-mature bolting. Fusarium wilt and lettuce aphid-resistant selections were advanced through selfing and backcrossing. A Fusarium wilt-resistant selection was crossed with an advanced Verticullium wilt-resistant selection as the initial step to combine resistances to these two destructive soilborne diseases. Genetic studies concurrent with breeding programs are being conducted to determine the inheritance of resistance to bacterial leaf spot, downy mildew, shelf-life of salad-cut lettuce, and Verticillium wilt. Publications during 2015-2017 included reports of original research on downy mildew, Verticillium wilt, bacterial leaf spot, shelf-life, thermotolerance, nutritional quality, marker-assisted selection, and development of molecular markers. |