reaction of pheno-morphological characteristics of lentil (lens culinaris medik.) cultivars to supplementary irrigation in mashhad conditions

supplementary irrigation is a key factor in dryland production of lentil (lens culinaris medik.). in order to study the effects of supplementary irrigation on phenological and morphological characters of three lentil (lens culinaris medik.) cultivars, a trial carried out as split block based on randomized complete block design with three replications at research field of agricultural college, ferdowsi university of mashhad. six treatments of supplementary irrigation (irrigation in all of phenological stages; once irrigation in each stage of branching; flowering; podding; seed setting, and also without irrigation in all growing season) as main plot (strip plot), and three lentil cultivars (robat; kalpoosh, and gachsaran) as sub plot were adjusted. results showed that one irrigation in flowering, podding, and seed setting stages increased significantly (p≤0.01) reproductive growth stage relative to irrigation in branching stage. the complete irrigation treatment increased growth stages of plant approximately 12% (based on degree day) relative to without irrigation treatment. the interaction of irrigation×cultivar on the vegetative growth and overall plant growth was significant (p≤ 0.01). in robat cultivar, delay in irrigation till seed setting stage compared to complete irrigation, decreased 9.5% the vegetative growth period (based on degree day), while irrigation in podding stage on kalpoosh cultivar compared to without irrigation, increased the number of growing degree day by about 9%. supplementary irrigation at the flowering stage increased number of branches per plant by 14% compared to the irrigation at the seed setting stage. while, supplementary irrigation during flowering stage increased the branch dry weight about 33% compared to the non-irrigation treatment. also, the supplementary irrigation at flowering stage compared to without irrigation increased the branch dry weight of robat, gachsaran, and kalpoosh cultivars about 17, 31 and 59%, respectively. the interaction of irrigation×cultivar was significant (p≤ 0.01) on branch length, and dry weight, also grain yield of lentil. the non-irrigation compared to the completed irrigation, reduced the branch length of gachsaran, and kalpoosh cultivars about 30 and 21%, respectively. supplementary irrigation during the flowering stage in comparison with seed setting stage, also was increased the branch length of robat, gachsaran, and kalpoosh cultivars 18, 23 and 27%, respectively. positive and significantly correlation were observed between vegetative and reproductive growth duration with stem length (r=0.26* and r=0.34**) and reproductive growth with branches length (r=0.34**), stem and branches dry weight (r=0.37** and r=0.41**) and yield (r=0.34**), respectively. also correlation between yield and stem length (r=0.32*), number of branches and branches length (r=0.44** and r=0.53**) and stem and branches dry weight (r=0.42** and r=0.36**) was positive and significant. based on above conclusions, one supplementary irrigation in flowering stage was more effective to improving growth characters and lentil yield.