Investigation on Allelopathic Effects of Shoot Aqueous Extracts in Bromus (Bromus japonicus. L.) Germination Characteristics and Seedling Growth Characteristics of Four Common Cultivars of Wheat (Treaticum aestivum L.) in Sistan Province

A study was carried out to investigate the allelopahtic effects of shoot aqueous extract of Bromus (Bromus japonicus L.) on germination characteristics and seedling growth of four common cultivars of Sistan wheat (Treaticum aestivum L.). The layout was conducted as factorial in a completely randomized design with four replications in Biotechnology Research Center (Bio-center), University of Zabol in 2014. The treatments were in four levels (25, 50, 75 and 100%) of shoot aqueous extracts of Bromus plus distilled water as control. The results showed when concentration of shoot aqueous extracts increased, germination percentage, germination rate, root length, stem length, root fresh weight, stem fresh weight, root/stem fresh weight ratio, root/stem length ratio, seedling length, root dry weight, stem dry weight, and seedling vigor index decreased significantly. The functional three-parameter logistic model provided a successful estimation of the relationship between aqueous extract level and germination response of cultivars of wheat. The fitted model showed that by increasing concentrations of shoot aqueous extract of bromus, maximum germination percentage of wheat cultivars was decreased. Hamun wheat cultivar was more tolerant to different concentrations of shoot aqueos extract of bromus than other cultivars. It showed 50% reduction in maximum germination percentage when extract concentration was about 148.2 %. However, in Bulani wheat cultivar 50% reduction was about in 61.93% extract concentration. As conclusion, Bulani wheat cultivar was more susceptible to different concentrations of extract of bromus than other cultivars.