Evaluation of lentil (Lens culinaris) genotypes for autumn sowing in cold temperate regions under field conditions

  In Iran, lentil cultivation areas are located mainly in the highlands with hard winters as for the susceptibility of cultivated, autumn sowing is impossible. Therefore, the cultivation is usually done in spring and rain fed. Sowing in low soil temperature in end of winter is one of the problems of spring cultivation in these areas. also, the stop of rainfall before the reproductive stage as well as the inappropriate distribution of rainfall causes moisture depletion of the soil and the most sensitive stages of growth faces with unfit environmental conditions. These factors decrease plant growth, the biomass yield and eventually grain yield. Grain yield can be increased by replacement lentil cultivation in autumn instead of spring cultivation with effectively using of environmental factors such as atmospheric precipitation. Autumn sowing lentil cold tolerant genotypes in Iran showed that this genotypes more effective than spring sowing (3). Cold and freezing are the most important factor limiting lentil cultivation in autumn crop. Identification lentil genotypes with cold tolerance potential is one of the suitable strategies for success in autumn lentil cultivation. Therefore, this experiment was designed to select cold tolerant genotypes of lentil in field conditions. In this study, the cold tolerance of 253 lentil genotypes were evaluated in 2015-2016 on Research Center for Plant Sciences, Ferdowsi University of Mashhad based on augmented designs. Planting was done in the early in November and the plants were exposed to the temperature below 0 °C for 40 days during the vegetative stage. The lowest temperature during this period was -5.9 °C. The cold tolerance of genotypes, was evaluated by a scaling method based on survival rate. The 253 lentil genotypes were classified into four groups of highly resistant to cold (100- 75%), cold resistant (74-50%), tolerant to cold (25-49%) and cold-sensitive (24-24%), respectively. During the growing season, the phonologic stages of the plants (days from sowing to flowering and flowering to maturity) and the survival percentage were recorded under winter cold. At the end of the growth season, in five randomly harvested plants, Morphological traits, yield and yield components were measured and recorded. Lentil genotypes showed the different cold tolerance and survival percentage (SU %) was between 0 to 100%. 23 genotypes (9 percent) Survived higher than 75% and were classified as highly resistant to cold. The highest survival percentage (100%) was observed in MLC8. The maximum grain yield (88 g.m-2) and biomass yield (535 g.m-2) were obtain from MLC415. The highest length in plant (41 cm) was observed in MLC291. The maximum number of filled pods (83 filled pods per plant) in MLC218 and the maximum hollow pods (72 hollow pods per plant) were observed in MLC72. Based on this results, 23 cold tolerant genotypes among 253 lentil genotypes were identified and selected for autumn sowing. It seems that by identifying cold resistant genotypes and improvement of vegetative and reproductive growth periods in autumn cultivation, it can be expected that crop yield will improve in autumn cultivation. However due to mild winter, further experiment is necessary for identification of cold hardy lentil genotypes.