Studies on vivipary in dwarf coconut cultivars

Abstract

Vivipary is a problem in some dwarf varieties of coconut as their seed nuts show low germination compared to Talls. An experiment was carried out to study the extent of vivipary in dwarf coconut varieties (MGD, MYD, MOD and CGD) with WCT as control. Observations on nut traits like shape, colour, length, weight and water content of the seed nut, thickness, weight and polyphenol content of the husk, length and weight of embryo, TSS of nut water were recorded from 10-, 11- and 12-month-old nuts of each variety. Observations were also recorded at bimonthly intervals during November 2011-September 2012. None of the ten-month-old seed nut exhibited vivipary. However, few 11th old MOD nuts (3%) harvested during November showed vivipary. The results showed that the extent of vivipary was highest during September and least during January. Among the varieties, MYD exhibited maximum vivipary (24%) followed by MOD and MGD (16%) and the least was in WCT (0.6%). Vivipary was negatively correlated with various nut characters, husk thickness and weight. However, prevailing climatic conditions like amount of rainfall, number of rainy days and relative humidity during the preceding 30-day of harvest had significant positive correlation with vivipary. It is suggested that vivipary in dwarf varieties can be avoided by harvesting the seed nuts at the proper stage.