Vegetative propagation of selected clones of cocoa (Theobroma cacao L.) by stem cuttings

Abstract

The government of Cameroon is responsible for distributing hybrid cocoa seeds to farmers in Cameroon. These high-yielding and pod rot-resistant hybrids are obtained from self-incompatible commercial clones used for seed production by manual pollination of freshly opened flowers. The experimental procedure for the propagation technique of these clones has never been reported. The objectives of this study are to assess the effect of clone, cutting source and growth regulator concentration on the growth and rooting of cocoa (Theobroma cacao L.) stem cuttings. The experiment consisted of 4 clones (SNK16, ICS40, UPA143 and T79/501; two cutting sources: B1 = orthotropic and B2 = Plagiotropic) and four concentrations of growth regulator (4-indol-3-butyric acid) concentrations (D0 = 0 mg, D1 = 12.5 mg, D2 = 25 mg and D3 = 37.5 mg), thus a 4 × 2 × 4 factorial experiment in a completely randomized block design with 3 replicates was designed. Cuttings were set and monitored weekly for shoot sprouting for 10 weeks and rooting at the 10 th week. The following parameters were measured: survival rate, number of cuttings with shoots, number of produced shoots, leaves length, number and length of produced roots. Clone, cutting source and growth regulator concentration significantly affected survival rate, shoot sprouting and rooting of cocoa cuttings at p = 0.05. Overall, cuttings started producing shoots 3 weeks after setting (WAS) and at 10 WAS all the cuttings had rooted. Assessment of cuttings in Clementine propagators showed a survival rate of approximately 75%, with orthotropic cuttings showing higher results than plagiotropic cuttings, whereas, D1 (12.5 mg) was the overall effective growth regulator (IBA) concentration that induced the highest number of roots from all the clones. UPA143 was the clone with highest value for all the factors assessed. The results will be valuable in management decision when producing planting materials by stem cuttings.

Vegetative propagation of cocoa (Theobroma cacao) by grafting: Aptitude of grafting on four clones

“…Moreover, it is precocious as it produces within a short time, unlike Clone 1 which is of the Amazonian origin. These findings line up with those of Essola et al (2017) who reported a mean survival of 45 and 52.57% for cuttings of SNK16 and T79/501 respectively. Similarly, Kamga et al (2018) obtained a 60% survival rate with hybrid cocoa cuttings, whereas Séry et al (2019) reported a 41.7% survival rate with Cola nitida cuttings.…”

“…Additionally, scions were gathered from genetically improved materials of four cocoa clones (Amazonia Highs: T79/501 -Clone 1 and IMC67 -Clone 2, and Trinitario: SNK16 -Clone 3 and ICS40 -Clone 4) established in the clonal seed orchard of SODECAO Nkoemvone. The characteristics of these clones were previously described by Essola et al (2017). Two treatments were applied on two grafting types: terminal slot grafting and English or side grafting.…”

CHITOSAN IMPROVES MORPHO-PHYSIOLOGICAL, ROOTING ATTRIBUTES AND PROFITABILITY OF TWO COCOA (Theobroma cacao L.) VARIETIES DURING VEGETATIVE PROPAGATION

“…The development of the CCN-51 seedlings was notably greater, so that after 120 days, they exhibited a growth of 1.05 mm, compared to 0.77 mm of the seedlings of the clone INIAP-EETP-801, which can be attributed to a greater adaptability of the seedlings of the first clone, as well as a greater development and production potential (Junior et al, 2017). In addition, this is supported by the foliar emission, which, at the age of 120 days, the seedlings of clone CCN-51, registered an emission of 4.64 leaves, compared to the increase of 4.26 in the INIAP-EETP-801 clone, being able to point out that the CCN-51 clone presents a greater development than the INIAP clone, however, these results are opposed to those obtained by (Reyes-Pérez et al, 2021), who observed that clone CCN-51 was characterized by plants of lower height, but with high productive potential at the field level.…”

“…Stem cuttings are a promissory propagation technique because of their quick an efficient performance (Reyes- Pérez et al, 2021). The propagation of cocoa clones by stem cuttings depends on the development of adventitious roots from the pericycle region at the stem base just above the cut and treating them with phytoregulators to promote root initiation (Junior et al, 2017).…”

Vegetative propagation of Combretum collinum Fresen. (Combretaceae), Combretum molle R. Br. ex G. Don (Combretaceae) and Piliostigma thonningii Schumach. (Fabaceae) by cuttings: Effects of rooting media and indole-3-butyric acid concentration

“…Earlier studies on other species have shown that cuttings from soft wood or juvenile branches are more successful than those from older plant tissue (Azad et al, 2016). The experiment was carried out under non-mist propagation tunnels (Junior et al, 2016;Qadri et al, 2018).The tunnel was made of 4m wide and a 4m long wooden box constructed from round wood measuring 60cm wide by 4cm thick. The box was placed over thick polythene sheets and then lled with sand base where polythene pots were placed to create humid chambers under a shade of 70% heat and light intensity penetration.…”