مطالعه القاى پلى پلوئيدي و سيتوميكسيس با كلشيسين در سه رقم ذرت خوشه ا ى (Sorghum bicolo)

Polyploidy and cytomixis induction in three cultivars of sorghum bicolor by colchicines treatment

Sweet sorghum (Sorghum bicolor) is a C4, drought resistant plant and it is an important crop in Iran. In this plant, larger vegetative parts, flowers and fruit is produced in comparison to their diploid ancestral by polyploidy induction. With this aim; this investigation was set out to determine the most suitable treatment for inducing polyploidy in sweet sorghum using colchicines. The colchicine application for three cultivars(Keller, IS4546 and RIO) are used, namely to seed, seedlings and shoot meristem of seedlings. In these methods colchicine concentration was 0-0.1 % for 6, 48 or 72 hours treatment. The percent of mortality for three cultivars of sorghum in all treatments were very high. Pollen mother cells from induced plants were used for tetraploidy study by colchicines. The normal chromosome number in control treatments (colchicine concentration was 0) of three cultivars was 2n=2x=20 but after colchicines induction, in pollen mother cells (pmcʹs) of these cultivars tetraploidy(2n=4x=40) reached to 18.25%. In cytology studies; addition of polyploidy; cytomixis, chromosomelagging and anioploidy were observed too by colchicine induction. The lagging phenomenon for IS4546 and RIO cultivars was 15 and 28%. Cytomixis in 3 cultivars; Keller, RIO and IS4546 were sequence 2, 5 and 7 percent.