A comparative study of the reproductive success of Theobroma Cacao L (malvaceae) undernatural and manual pollination

Abstract

The reproductive successes under natural and manual pollination were assessed. Two cocoa farms around Bobiri Forest Reserve, in the Ejisu-Juabeng District Ghana were purposively selected. Fifteen percent of open flowers from five selected cocoa trees were subjected to manual-pollination and total exclusion. Ninety pods under natural pollination were compared with ninety pods under manually pollination. Proximate analysis was carried out to evaluate the macronutrients of cocoa pod and seeds produced under the two pollination modes. Results show that pollinator exclusion significantly decreased fruit set (df=2, X2 =12.5, P=0.00) and flower set (df= 2, F=25.2, P=0.00) (P=0.00). Pod weights and seed numbers significantly differed (V=0.049, F (4.49)=0.986, p<0.01, eta squared=0.049) irrespective of pod size and mode of pollination, however, there were individual differences. Weights of small pods did not differ (p>0.05) under the two pollination regimes, however, weights of medium size pods (p < 0.05) and that of the large pods (<0.05) produced under the two regimes of pollination differed. Number of beans and the size of pods did not differ under the two modes of pollination. Linear relationship existed between weight (y) and seed number (x) of individual pods: Y=18.56 + 0.016x; R2 =0.45. Macronutrients of pods and seeds did not differ (paired t test= 4.08, 29 d. f.; P=0.12) under the two pollination mode. The study concluded that natural pollination contributed to cocoa production.