Study the Autoallelopathic potential of seed hull of ten Iranian rice cultivars (Oriza sativa L.) on germination and rice seedling growth

In order to study the effects of four concentrations (check, 5, 10 and 15%) of hull extracts on growth of 10 iranian rice cultivars, two experiments were conducted in completely randomized block design with factorial arrangement and three replications at two sites, laboratory and greenhouse. Laboratory study showed that same rice hull extracts had stimulat effects and the others had inhibitory effects on seedling growth of the same cultivar. Behnam Chalos cultivar showed the highest stimulation on germination percentage, root length and total dry weight of seedlings. The rice hull extract of nemat and tabesh exhibited the most stimulation on shoot length and germination rate of the same seedlings, respectively (P≤0.01). The result of greenhouse research suggested that rice hull extract of nemat cultivar had the greatest stimulatory on shoot length and root dry weight of the same seedling. Root length in tabesh cultivar, germination rate and total dry weight in gerdeh cultivar and shoot dry weight in zarak cultivar were more stimulated than other cultivars (P≤0.01). The results suggest that various allelopathic effects (inhibition and stimulation) exist in rice hull extract of different cultivars. Rice hull extract from breeding cultivar contrary to native cultivars had the greatest stimulatory on seedling growth. Enhanc of aqueous extract concentration increased stimulation effects on seedling traits in breeding cultivars. Length and dry weight of seedling root was decreased in rice native cultivars under rice hull extract (P≤0.01).