Floral biology and the compatibility system in ciku cv. Jantung (Manilkara achras)

J. Indu Bala

Abstract

The investigation was initiated to identify and understand fully the reproductive biology of ciku cv. Jantung. Trials were conducted to determine the floral biology, efficiency of pollen transfer and the system of pollination. Based on the changes in the external morphology of ciku flower buds, four stages of floral development were identified; stages 1–3 at bud stage and stage 4 at flower opening. At stage 2, the anthers dehisced and released pollens. The pollens only became viable and functional at stage 4, i.e. at anthesis. The stigma was receptive from stage 2 to 3 but was at its peak at stage 3, i.e. a day before the flower opened. These results therefore showed that there was little or no overlapping between the staminate and the pistillate phases (temporal separation) of ciku cv. Jantung. This was further confirmed with the pollination trial where only 4.8% of fruit set was obtained when the flower buds were bagged. The presence of temporal separation in ciku cv. Jantung limits within-flower pollination and therefore favours outcrossing. However, the relatively high fruit set (65%) obtained from the assisted self-pollination trial further suggests that ciku Jantung is self-compatible. Although within-flower pollination is limited, between flower pollination can occur extensively as the flowers are self-compatible.

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