Study of seed germination and seedling growth of alfalfa genotypes (Medicago sativa L.) under drought tension conditions

In order to investigate the effect of drought tension on germination characteristics and seedling growth of 10 alfalfa genotypes, two separate experiments were carried out in vitro petri dish culture medium (seed testing) and potting (vegetative growth stage) as a factorial experiment in a completely randomized design with three replications in a specialized laboratory in Khuzestan University of Science and Research in 2014. The factors in both experiments consisted of five levels of drought tension including: zero, 0/4, -0/6, -0/9 and -1/1 MegaPascal and 10 genotypes of alfalfa include: KFA1, KFA3, KFA12, KFA15 (Nagorno origin alfalfa), KFA4, KFA5, KFA16 (Hamadani origin), KFA9 (Chaleshtar Shahrekord origin), KFA7 (Rehnani origin) and the tropical Yazdi. The seed testing results showed that drought tension significantly reduced germination factors, including germination percentage, germination rate, average daily germination, root length and dry weight. In vegetative growth stage, traits of root length and seedling length, seedling dry weight decreased with increasing drought tension. The highest Sensitivity Index (SSI) was assigned to KFA3 and KFA7 genotypes with mean values of 1/11 and 1/1, respectively.