Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 1, 2001
Publication Date: N/A
Interpretive Summary: Lettuce is a food plant; the leaves are consumed. Early flowering is useful for educational purposes because of the short life cycle, as a tool for speeding up the plant breeding cycle, and for studying growth and development processes.
Technical Abstract: Genes for early flowering have been reported in several plant species, including pea, turnip rape, wheat, rice, soybean, and common bean. In lettuce, two genes for flowering time have been reported previously. Both genes are partially dominant, encompassing a total range of 100 days of flowering time. The double dominant genotype, Ef-1Ef-1Ef-2Ef-2, is the earliest flowering combination of the two genes. In summer in the greenhouse, the two genes reduce flowering time to about 45 days, as compared to 140 days for a normally flowering crisphead lettuce. A population of the genetic line 87-41M, which combines a gene for endive-like leaf with the early flowering trait, produced plants with an earlier flowering time than expected. One plant was crossed with another early flowering line, D-3-22M. Investigation of the F2 and of F3 families showed that a third dominant gene was segregating, which reduced flowering time by 9 days from that of the double dominant genotype of the original material. Also, the height of the seed stalk was reduced by about ten centimeters. The usefullness of early flowering genes as an educational tool and as a means of accelerating the breeding cycle will be discussed.