Effect of cross- and self-pollination on 2-acetyl-1-pyroline content and other fruit characteristics of aromatic coconut (Cocos nucifera Linn.)

The Thai aromatic coconut cultivar 'Nam Hom' is famous for its unique aroma. 2-acetyl-1-pyrroline (2AP) is believed to be the compound responsible for it sweet fragrance, however, in certain circumstance the aroma diminished. It was thought that cross-pollination may be one of the causes. A study on artificial pollination of 'Nam Hom' female flowers (H) with pollen from 'Nam Hom' (H), 'Nam Wan' (W), 'Thai Tall Red' (TTR) and 'Nam Hom' self-pollination (Self) revealed that 2AP was found in the water of all fruits, at 7 months after flowering, from all crossings. However, fruit from H×W had the lowest 2AP content, while the other crossing had similar 2AP levels. It was also found that H×TTR had the highest sugar content and turbidity in its water. These results indicated that the xenia effect occurred in cross-pollination of 'Nam Hom' coconuts. Moreover, meta-xenia effects were also found as shown by the smaller fruits and shells in H×W, while the H×TTR crossing had bigger fruits and shells as compared to H×H and Self.