In order to evaluate phenological characteristics, yield and yield components of 18 cold tolerant lentil genotypes in fall planting under supplementary irrigation, an experiment was carried out based on randomized complete block design in 2006-2007 at Research farm of college of agriculture, Ferdowsi university of Mashhad. Irrigation was performed three times: immediately after sowing, 20 days after that and at flowering stage. Based on results, the differences among genotypes for all traits were significant (p≤0.05). The range of vegetative period (emergence to flowering) among genotypes varied from 102 to 150 days. Numbers of branches per plant were different from 5 to 24. In addition, seed yield was observed to change from 76 g.m-2 in MLC13 to 379 g.m-2 in MLC20. Correlation between seed yield and vegetative growth period (r=0.79**), reproductive growth period (r=0.83**), plant height (r=0.62**), number of branches per plant (r=0.68**), length of branches per plant (r=0.56**) and numbers of pod per plant (r=0.80**) were positive and significant. Regarding to four times increase in seed yield in this experiment compared to average lentil seed yield in Iran, we predict an outstanding increase in producing of lentil in fall planting of cold tolerant lentil genotypes under supplementary irrigation.

Key words: Branch, Cold tolerant, Phenology, Vegetative, Yield