القاء موتان ساقه كوتاهي در واريته برنج دمسياه

Induction of short culm mutant in Domsiah rice (Oryza sativa L.) Variety

Domsiah which has a high quality characteristics is a local rice variety in Iran but it is tall and sensitive to lodging. This study was conducted to induce short culm character in Domsiah rice from 1995 to 1998. Seeds were irradiated with gamma rays at 100, 200 and 300 Gray; and DMA at 0.1%, 0.2% and 0.3%, (for 24 hrs, in room temperature), seperately. The irradiated seeds were seeded in nursery and then transplanted in main land. At the end of the first season, main panicle of some randomly selected plants were harvested and planted in M2 generation as a panicle-to-row. Results showed no significant variation among the DMS treatments, hence these treatments were removed from the experiment. A short culm mutant line was obtained from 300 Gray gamma rays in M2 generation. This mutant line showed no segregation in M3 generation. In order to study some morphological characters in M3 generation, the mutant line and control were planted. Then, 15 plants were collected from the short culm line seperately and were planted in M4 generation in 15 distinct rows. There was no significant difference in panicle length among short culm mutant lines and control. However, there were significant differences among culm mutant lines for plant height, tiller no., length and width of flag leaf. Meanwhile, the intra-variation in short culm mutant lines were negligible. The height of short culm mutant lines were about 60 cm shorter than the control (165 cm) but tiller number was significantly more than the control. The reduction of internode 2 through 5 caused the height reduction in short culm mutant lines.