EVALUATION OF FLORAL EVENTS FAVOURING CROSS POLLINATION IN STRAWBERRY (FRAGARIA ANANASSA DUCHESNE CV. CHANDLER) FLOWERS UNDER SUBTROPICAL NORTH INDIAN CONDITIONS

摘要

In the north Indian subtropical conditions, the average life spun of strawberry (Fragaria x Ananassa Duchesne, cultivar Chandler) (lowers was 17.0±6.8 days (range 11.4-25.5 days), being maximum in secondary flowers (20.0±6.3 days) followed by primary (16.3±7.5 days) and terliary (lowers (14.8±6.5 days). The pre- anthesis, anthesis and post-anlhesis stages overlapped each other and lasted for 9.9±3.7, 3.9±1.9 and 3.2±1.1 days, respectively. In bud stage A (petals not visible) flowers remained lor a mean period of 1.1±1.1 days, whereas, in B stage (petals visible but not expanded) for 3.2±1.9 days and in C (petals expanded) for 5.5±2.l days. For 1.8±l.0 days anthers were in D_1 stage (anthers visible but did not dehisce) and for 2.2±1.2 days in anlhcsis stage (D_2). From the perspective of pollination, anthers remained exposed for maximum duration in secondary flowers (4.4 days) followed by primary (4.1) and tertiary flowers (3.2 days). All the pollen grains of strawberry flowers in the age group of 0-5 days were viable. Whereas, all the stigmas were non-receptive on 0 day-old-flowers (DOF) and less than 5 percent (on lower side of receptacle) in 1 DOF. The stigma receptivity increased to more than 95 percent in 2 DOF and all of them were receptive in 3,4 and 5 DOF. Such asynchrony of periods of pollen viability and stigma receptivity (by 2 days) favoured cross-pollination.