Advancements in utilizing molecular markers in lettuce breeding

Authors: Simko, Ivan

Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 10/26/2016
Publication Date: 3/7/2017
Citation: Simko, I. 2017. Advancements in utilizing molecular markers in lettuce breeding. 4th International Symposium on Molecular Markers in Horticulture, International Society for Horticultural Science. March 7-10, 2017, Napier, New Zealand.

Interpretive Summary:

Technical Abstract: Lettuce (Lactuca sativa L.) is globally the most popular commercially produced, leafy vegetable, farmed in moderate climates. Cultivated lettuce is a self-fertilizing, diploid (2n = 2x = 18) species from the family Compositae (Asteraceae). New cultivars of lettuce are developed by combining desirable alleles from the existing cultivars old, local, or primitive accessions, and by introgressing novel (usually resistance) genes from wild Lactuca species that are sexually compatible with cultivated lettuce. However, the development of elite lettuce cultivars is a slow and labor-intensive process that involves cross-pollination, several rounds of selections in field and/or greenhouse conditions, development of homozygous lines, and testing of breeding lines for their performance. Molecular markers that facilitate selecting desirable genotypes more efficiently thus shorten the time needed for the development of new breeding lines and cultivars. Here, I evaluate the progress in development and use of molecular markers for marker-assisted selection. At the present time, marker-assisted selection in lettuce is limited to simply inherited traits such as race specific resistance to downy mildew, corky root, lettuce mosaic, lettuce dieback, and Verticillium wilt. The new marker-assays are being developed through the collaboration with universities and private industry for the detection of alleles involved in post-harvest decay of fresh-cut lettuce, premature bolting, and improved markers for the resistance to race 1 of Verticillium wilt. Tests were performed to analyze utilization of molecular markers in genomic selection for the traits with polygenic mode of inheritance.