Abstract

Sexual behaviour including flowering process, anthesis, sorosis and seed formation was observed in six promising mulberry varieties namely Chinese White, Chak Majra, S146, Kanva-2 (Morus alba), Sujanpur and Mandalay (M. indica) under sub-tropical conditions. The time taken for complete opening of first buds ranged from one to five days. The varieties were either exclusively females (Kanva-2 and Sujanpur), monoecious (Chinese White, Chak Majra and S146) or predominantly monoecious with dioecious plants (Mandalay). The time taken for attaining maturity of female flowers within a variety ranged from a minimum of 4-5 days in Kanva-2 and Sujanpur to a maximum of 7-11 days in Chak Majra. The period of attaining maturity of male flowers ranged from 6-7 days in Mandalay (M. indica) to a maximum of 9-13 days in Chak Majra (M. alba). Receptivity period lasted to a maximum of 3-4 days and the dehiscence of anthers was complete within a period of 4-6 days. Pollen viability ranged from a minimum of 88.02% in Chak Majra (M. alba) to a maximum of 99.15% in Mandalay (M. indica). The sorosis maturation was complete within 43 days in Chak Majra (M. alba) to a period of 68 days in Mandalay (M. indica). The time taken for attaining complete colouration of the berries within a variety ranged from a minimum of 2-8 days in Chak Majra (M. alba) to a maximum of 23-25 days in Sujanpur (M. indica). The shape of the berry ranged from sub-globular in S146 and Sujanpur to cylindrical and elongated in Chinese White. The single sorosis weight ranged from a minimum of 1.055 g in Chinese White to a maximum of 1.750 g in S146. The number of achenes per berry (40.40) were more in S146 (M. alba) and less (29.20) in variety Mandalay (M. indica). Seed setting percentage ranged from a minimum of 9.53% in Chinese White (M. alba) to a maximum of 79.53% in Mandalay (M. indica). Varieties Sujanpur and Mandalay, representing M. indica produced heavier seeds. The seed viability ranged from a minimum of 58.00% in variety Mandalay (M. indica) to a maximum of 89.90 in variety S146 (M. alba).

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