Document Type : Full Paper
Former Ph.D. Student, University College of Agriculture & Natural Resources, University of Tehran, Karaj, Iran
Instructor, Vegetable Research Center, Horticultural Research Institute, Agricultural Research, Education and Extention Organization, Karaj, Iran
Associate Professor, University College of Agriculture & Natural Resources, University of Tehran, Karaj, Iran
Professor, University College of Agriculture & Natural Resources, University of Tehran, Karaj, Iran
Professor, Seed and Plant Improvement Institute, Karaj, Iran
One of the effects of climate change and global warming, on leafy vegetables production, is bolting. The four parental lines derived from Iranian lettuce landrace of Shirazi, Zeareei and Siah with difference in flowering time crosses between each pair and F1, F2, BC1p1 and BC1p2 generations were obtained. Transplants were planted in two separate experiments in a randomized complete block design with three replications and flowering time, head weight, number of leaves and leaf length of biggest outer leaf were recorded. Generation mean analysis showed that in all traits additive dominant model was inadequate and other factors such as epistasis is effective in controlling interested traits. The effect of additive is significant but the effect of dominance is much greater than it. The additive × additive effects and dominance× dominance effects on traits have been effective. To determine the number of effect factors at the flowering time of the F2 segregation and two genes involved in controlling flowering time were confirmed. Results showed that late flowering lines of the Siah and Zeareei landrace produced better quality and quantity head than early flowering lines of Shirazi landrace. Thus flowering time, leaf number and head weight had positive correlation. It is expected that selected genotypes with late flowering time had good potential for this important traits and should be used in breeding programs.