Comparison of Grafting Techniques and their Effects on some Growth Parameters of Ten Elite Cocoa Clones (Theobroma cacao L.)

Abstract

Cocoa productivity in Côte d'Ivoire has been on a downward trend for the last decades due to many factors key among them being the non-availability of quality planting materials. However, some elite clones developed in the country are available and need to be adopted by farmers. This study was conducted in Soubré, Côte d'Ivoire to evaluate the grafting techniques (top grafting and budding) success of 10 elite cocoa clones and their effects on selected growth parameters in the nursery and field. Experimental design was a split plot with grafting technique as main factor and clones as subplot treatment replicated three times. Data were collected on shoot emergence 1 to 5 weeks after grafting (WAG) and grafting success at 10 WAG. Our results showed shoot emergence from top grafting but not on budding 1 WAG. In addition, the number of leaves was high in top grafting (11) compared to budding (5); the same trend was observed in the field. There were no significant differences between both techniques for the grafting success; meanwhile success was 77% and 68% for top grafting and budding, respectively. However, there was better vegetative growth on seedlings grafted using top grafting than budding and this technique seems to be the best to graft cocoa in the nursery.

Successful grafting elite cocoa clones (Theobroma cacao L.) as a function of the age of rootstock

“…Therefore, according to the current work, to ensure a good resumption of the graft, it is necessary to do the grafting at an advanced age of the rootstock from three (3) months to 4-months in the nursery. The current results, in accordance to those of [ 11 , 22 ] could be explained by the fact that rootstocks of advanced age (3 months and 4 months) have a large reserve of hormones and can easily renew and regenerate their cells while that of 2-month-old with lower success could be attributed to the low carbohydrate reserves. Our results concur also to those of [ 14 , 36 ] who stated that rootstock age is affected by regenerating ability of plant slices due to the differential activity of meristematic cells.…”

“…Graft success depends on the rootstock-scion physiological compatibility and the proper alignment of tissues in the graft union [ 22 , 38 ]. The low grafting success recorded for some clones implies a relative mortality rate of the cocoa clones' seedlings.…”

“…Various studies were conducted to assess the grafting success rate, the growth, and the performance of the cocoa seedlings by Refs. [ 12 , 16 , 22 ] in order to choose the best clones to be promoted to sustain the production in the field. The performance of this technique on cocoa farming was assessed in Côte d’Ivoire through 10 new elite cocoa clones coded C1, C8, C9, C14, C15, C16, C17, C18, C20, and C21.…”

“…Nevertheless, a study conducted by Ref. [ 22 ] compared two grafting techniques (budding and top grafting) in nursery and their effects on some growth parameters of ten elite cocoa clones in Côte d’Ivoire conducting to the result that the success rates were 68% and 77% for budding and top grafting, respectively. Recently [ 9 , 12 ], reported on the compatibility of ten elite cocoa clones grafted on mature trees and on the growth and development patterns of the same ten elite clones grafted in nursery in Côte d’Ivoire, respectively.…”

Socio‐ecological benefits of fine‐flavor cacao in its center of origin

“…Combining different genotypes in the rootstock (the mother tree) and the scions, grafted on the pruned mother tree, may be optimized to maximize pollination success and fruit set (Vansynghel, Ocampo‐Ariza, Maas, Martin, Thomas, Hanf‐Dressler, Schumacher, Ulloque‐Samatelo, Tscharntke, et al., 2022 ). Grafting of old trees can be easily performed with standard grafting practices (Daouda et al., 2018 ), and field experiments with Piura white cacao (Ocampo‐Ariza et al., 2022 ) showed that after ca. 2 years yield levels can be 40%–80% higher than in non‐grafted neighboring trees (unpublished data).…”