Introduction of clones from genetic groups that are underrepresented in the pedigree of commercial cacao varieties in West Africa represents an important aspect of cacao improvement strategy of broadening the genetic base to overcome current yield stagnation of the crop. The objective of the present study was to determine the combining abilities of more recently introduced cacao clones for yield and cropping efficiency in the early bearing years. Seven recently introduced clones were crossed as males to five clones commonly used in the seed gardens in Ghana using a North Carolina II design. The 35 F1 varieties and one commercial variety were evaluated in the field from June 2010 to March 2015 for four traits: increase in trunk cross-sectional area in the juvenile, and in the pod-bearing phases, bean yield and cropping efficiency. Though both GCA and SCA variances were significant for all traits, the ratios of GCA:SCA were much smaller than unity, indicating the importance of non-additive effects in the control of the traits. Among the set of clones therefore, prediction of F1 variety performance cannot be based on the GCA or per se (average) performance of the clones. Six varieties were more precocious, and eight had higher cropping efficiencies than the standard variety. Bean yields ranged from 0.74 to 1.05 t/ha/year in the fourth and fifth years after planting among the top six varieties. The study provides evidence of the large potential for productivity increase through the use of cacao clones beyond Pound's early introductions into West Africa.

Floral characteristics related to pollination were studied in four species of Theobroma and one species of Herrania (Sterculiaceae) in Costa Rica. Anthesis was complete in T. cacao, T. simiarum, T. speciosum, and T. mammosum at 0615 hr following an extended period of floral development throughout the night. Flowers of both T. cacao and Herrania cuatrecusana were fully open by dawn and pollen sacs dehisced throughout the morning hours. Stigma and style receptivity, assessed by hydrogen peroxide tests, were high throughout the morning and early afternoon in T. cacao. Bagged flowers resulted in no fruit-set. When petal ligules were experimentally removed there was no change in rates of flower abortion or total numbers of aborted flowers, tentatively suggesting that these structures play little or no role in attracting pollinators. Both Theobroma and Herrania flowers possess ultraviolet light reflectance'absorbance patterns which may play a role in pollinator attraction. Uptake of neutral red stain in T. cacao and T. simiarum showed scattered glandular activity on petals and sepals, perhaps indicating location of nectaries or other secretory organs. Conspicuous glandular trichomes on the ovary, on the lower third of the style, and in a conspicuous “basal ring” between petals and sepals (most pronounced and colorful in species other than T. cacao) may be sources of both floral attractant and reward.

Differences in floral biology among Theobroma and Herrania species suggest divergence in pollination strategies. The data presented are discussed in terms of plant-pollinator specializations in the New World tropics.