Genotypic variation in flowering, fruit set, and cherelle wilt, and their relationship with leaf nutrient status in cocoa (Theobroma cacao L.) grown in humid tropics of India

Abstract

Cocoa is an important plantation crop grown for its beans, used in the chocolate and confectionary industry. It produces a large number of perfect flowers on the stem (cauliflorous), but the fruit set is low. There is a lack of comprehensive information regarding the genotypic variability in flowering, fruit set, and cherelle wilt, as well as their relationship with leaf nutrient status. Thus, a field study was undertaken at ICAR-Central Plantation Crops Research Institute, Regional Station, Vittal, to elucidate the influence of leaf nutrient status on flowering, fruit set, and cherelle wilt in cocoa. The study revealed significant variations among twenty cocoa genotypes for flower production, fruit set, and cherelle wilt. The highest number of flowers (106) produced on a one-meter marked area on the stem and fruit set (13.7) was recorded in VTLC 05. The lowest number of flowers was observed in genotype VTLCH 2 (16). The maximum fruit set percentage was found in VTLC 182 (13.8%), whereas the minimum fruit set percentage was observed in VTLC 30A (1.3%). Cherelle wilt was maximum in upper Amazon clone VTLC 155 (72.9%), whereas the lowest cherelle wilting percentage was recorded in VTLC 148 (22.9%). Pearson’s correlation coefficients indicated that fruit setting percentage in different genotypes had no significant association with leaf nutrient status, except for calcium which had a significant association (r = 0.596). The result indicated that genotypic variability exists for fruit set and cherelle wilt, and an optimum level of calcium should be maintained in the leaf for better fruit setting in cocoa.