Cytomorphological studies in triploid mulberry evolved by diploidization of female gamete cells

Triploids were successfully evolved in mulberry by diploidizing female gamete cells of Morus alba var. Kanva-2 with 0.2%, 0.3% and 0.4% colchicine treated for 8 hours for consecutive 3 days and by crossing them with monoecious diploid mutant. The triploids are characterized by increased growth and rooting habit; weight, size and water content of leaves, size of stomata and number of stomatal chloroplast and reduction in frequency of stomata per unit area and internodal distance have been recorded. Meiosis is highly irregular and characterized by the presence of a high frequency of trivalents and univalents. Various types of chromosomal associations, presence of tetravalents, unequal distribution and precocious movements of chromosomes, laggards, bridges at metaphase I and II, cytomixis at metaphase I and II, telophase I and II, dyads and tetrads stages and varying number of microspores have been frequently observed in the PMCs. The reduced pollen fertility has been attributed to various meiotic anomalies. Maintenance and commerical exploitation of triploids with desirable characters on large scale is feasible by vegetative multiplication.