Polyploidy induction and its effects on some morpho-physiologic characteristics in sorghum (Sorghum bicolor cv. KFS2)

Chromosome manipulation of the plant species for development of genetic variation in morpho-physiological characteristics is a powerful tool in plant breeding. This experiment was conducted at Mohaghegh Ardabili university, Iran, in 2013 to induce tetraploidy in sorghum seed, seedlings and terminal buds of sorghum were treated with colchicine (0.025, 0.05, 0.1 and 0.2%) for 8, 24 and 48 hours. Determination of tetraploid plants was done through the morphological, stomatal and karyological studies. The 0.025% of colchicine for 48 hours and 0.1% of colchicine for 24 hours were the effective treatments for production of tetraploid plants in all treatment. Comparison of diploid and tetraploid plants showed that tetraploid plants had less stomata number but with greater size. Thickness of leaves, plant height, leaf length and width, stem diameter, number of leaves and panicle length and diameter were also higher in these plants. In addition, tetraploid plants had fewer or equal node number with diploid plants, but longer internodes. The chlorophyll, carbohydrates, total soluble protein content of leaf and antioxidant enzymes activity were significantly greater in tetraploid plants. The protein expression patterns studied by SDS-PAGE represented an increase in density of the protein bands in tetraploid plants as compared with diploids. In conclusion, polyploidy induction can be effectively employed in improvement of some morpho-physiological traits in sorghum.