ISHS Acta Horticulturae 820: VIII International Mango Symposium
GENE FLOW IN MANGO ORCHARDS AND ITS IMPACT ON YIELD |
| Authors: | A. Dag, C. Degani, S. Gazit |
| Keywords: | Mangifera indica, pollination, pollen, isozyme, selective abscission |
| Abstract:
Understanding the dependence of fruit trees on cross-pollination is crucial when planting a new orchard. If the cultivar is self-fruitful, a solid block can be planted, but if it depends on cross-pollination, at least two compatible cultivars must be interplanted. Postzygotic self-incompatibility has been reported in several commercial Indian cultivars, and this prompted us to study this phenomenon in Floridan cultivars. Isozyme analysis enabled us to determine the pollen parents of fruits in several mango orchards. Sampling and analysis were carried out shortly after fruit set and again when the fruits reached maturity. When feasible, yield was recorded also. The hybrid rate was consistently and significantly higher among mature fruits than among young ones, indicating a greater abscission rate of selfed fruitlets. This selective abscission amplified even an initially low primary hybrid ratio, resulting in a high hybrid rate at maturity. This hybrid rate gradually decreased with increasing distance from the pollenizer, but even at a great distance from the pollenizer the hybrid rates were still substantial. In one orchard, the hybrid rates in ‘Kent’ were 14% at the 9th row from the 'Maya' pollenizer, in the second orchard, it was 26% at the 20th row from the 'Palmer' pollenizer. In a third orchard, we found 31% hybrids in 'Maya' at the 17th row from 'Tommy Atkins'. We were able to record the yield only for 'Maya': it was not affected by the distance from the pollenizer, and there was no correlation between the hybrid rates and the yield. Therefore, we conclude that cross-pollination is not a yield-limiting factor in 'Maya' and that the practice of planting 'Maya' in solid blocks is sound. These results are similar to our previous findings for 'Tommy Atkins'. | |
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