No abstract

In Sulawesi, Indonesia, cocoa smallholdings are seriously affected by the cocoa pod borer (Conopomorpha cramerella, CPB). CPB is detrimental to both cocoa production and bean quality, and is a major concern to cocoa smallholders, processors, exporters and the international market. An Australian Centre for International Agricultural Research (ACIAR)-funded project was initiated to develop a locally applicable, farmer-participatory methodology for selecting and testing promising cocoa genotypes on farms. In a trial established on a farm in SouthEast Sulawesi, local Indonesian and international cocoa selections were propagated clonally by side-grafting onto mature trees of mixed genotype and evaluated for 2 years for pod value, quality and resistance to pest/diseases. Local selections were based on the observations of farmers, extension officers or researchers and included a number of clones specifically selected for resistance (or susceptibility, as checks) to CPB. Our results on the CPB-infestation of 34 clones in the trial indicate the potential of employing on-farm selection and testing to improve cocoa farms. Severity of infestation was determined in ripe pods according to whether the proportion of beans damaged by CPB larvae was light (less than 10%), moderate (10-50%) or severe (over 50%). Total CPB incidence in ripe pods for most of the clones was high, exceeding 75%, and was correlated with severe and light incidence, both of which varied more. The data support a model that predicts severe infestation inflicting bean losses occurs above a critical threshold of total CPB incidence. The cumulative CPB incidence in infested pods was significantly lower in a local selection, Aryadi 2, which also had fewer larval entry holes and a low exit/entry ratio indicating a degree of resistance to CPB. The incidence of lightly infested pods was significantly lower in the susceptible controls. Pod hardness was moderately high in Aryadi 2. However, VSD3 (a local selection), Scavina12, KKM22 and BR25, had low levels of severe infestation and/or high incidences of light infestation, but had relatively soft pods. This suggests that factors in addition to pod hardness might be involved in resistance, a possibility also supported by the positive correlation of CPB incidence in ripe pods with that in immature pods and the larger seasonal fluctuations of CPB incidence observed in resistant clones, compared to susceptible clones. In a mixed genotype stand, the lower CPB incidence observed in some clones might be explained partly by pest non-preference.

Climate change is universal phenomena which is importantly anticipated including cocoa plantation. Drought tolerance cocoa seedling is urgently neededto develop cocoa plantation. This paper studied possible drought tolerance of cocoa seedling through crossing between female parent KKM 22 with three maleparents BAL 209, KW 641, and KW 614. Progeny test was conducted in green house based on four water availability conditions: 25, 50, 75, and 100%. Root condition was recorded as rootstock parameters of three crossings. Result showed that root characteristics varied among crossing samples studied. The longestand hight volume root were recorded from KKM 22 x BAL 209 crossing. Seedling of KKM 22 x BAL 209 crossing tended to have long and wide root, while seedling of KKM 22 x KW 641 crossing tended to have a wide root type and seedling of KKM 22 x KW 614 tended to have a long root type. Based on drought tolerancy, seedling of KKM 22 x KW 641 crossing could be classified as drought tolerance while other two group progenies could be classified as susceptible to drought.To conclude, seedling of KKM 22 x KW 641 can be recommended for cocoa plantation in drought area.

The cocoa industry in Sulawesi, the main region of cocoa production in Indonesia, is threatened by destructive diseases, including vascular-streak dieback (VSD) caused by the basidiomycete Oncobasidium theobromae and stem canker and Phytophthora pod rot (PPR) or black pod, caused by Phytophthora palmivora. Using the considerable genetic diversity of cocoa on farms, host resistance was identified and tested with the participation of farmers. Fortynine local and international cocoa selections with promising resistance characteristics (as well as susceptible controls) were side-grafted onto mature cocoa in a replicated trial with single-tree plots. Developing grafts were assessed in the dry season for severity of VSD infection, scored from 0 (no infection) to 4 (graft death). All of the 49 clones in the trial became infected with VSD in at least some replicates. Average severity varied from 0.2 to 1.6. Potential VSDresistance was found in eight clones, including DRC 15, KA2 106 and a local Sulawesi selection, VSD2Ldg. Some of the most susceptible clones were local Sulawesi selections from areas with a history of little or no VSD. Thirty-four pod-bearing clones were evaluated over a 2-year period for yield, quality and resistance to natural infections of PPR. Cumulative PPR incidence for all clones was 22% but varied from 8.6 to 43% among clones. Clones with less than 15% PPR incidence were designated as resistant, including DRC 16 and local Sulawesi selections, Aryadi 1, Aryadi 3 and VSD1Ldg. Scavina 12 was moderately resistant in the trial with a PPR incidence of 23%. Cumulative incidences of the mirid, Helopeltis spp., determined in the same evaluation period, indicated that DRC16 was the most susceptible clone with an incidence of 52% in ripe pods and 23% in immature pods. In comparison, KKM4 showed evidence of resistance to Helopeltis spp., with incidences of 34 and 0.8% in ripe and immature pods, respectively. The impact of diseases and pests (including cocoa pod borer) on bean losses and bean quality varied between clones but generally the bean size (or bean count) was affected more than the fat content or shell content.

Indonesia is the third largest cocoa-producing country in the world. Knowledge of genetic diversity and parentage of farmer selections is important for effective selection and rational deployment of superior cacao clones in farmers’ fields. We assessed genetic diversity and parentage of 53 farmer selections of cacao in Sulawesi, Indonesia, using 152 international clones as references. Cluster analysis, based on 15 microsatellite markers, showed that these Sulawesi farmer selections are mainly comprised of hybrids derived from Trinitario and two Upper Amazon Forastero groups. Bayesian assignment and likelihood-based parentage analysis further demonstrated that only a small number of germplasm groups, dominantly Trinitario and Parinari, contributed to these farmer selections, in spite of diverse parental clones having been used in the breeding program and seed gardens in Indonesia since the 1950s. The narrow parentage predicts a less durable host resistance to cacao diseases. Limited access of the farmers to diverse planting materials or the strong preference for large pods and large bean size by local farmers, may have affected the selection outcome. Diverse sources of resistance, harbored in different cacao germplasm groups, need to be effectively incorporated to broaden the on-farm diversity and ensure sustainable cacao production in Sulawesi.

ENSO (El Nino Southern Oscillation) occurring in 2015 in Indonesia caused drought stress and the decrease in the percentage of production and even death of plants. One effective and relatively inexpensive way of reducing damage and economic losses due to drought is the availibility of tolerant cocoa. The objective of this research was to obtain tolerant clones based on morpho-physiological characters under drought stress. The experiment was conducted in Kaliwining Experimental Station of Indonesian Coffee and Cocoa Research Institute (ICCRI) during dry season (El Nino period with 5 consecutive dry months, from May to October 2015). Stomata, proline, leaf water status was measured at the peak of dry season on tested cocoa clones. The cocoa clones that predicted tolerant against to drought stress were KW 641, KW 514, KW 535, KW 619, and KW 516, whereas the cocoa clones that predicted susceptible under drought stress were KW 609, KW 614, KW 635, KW 606, and KW 651. The treatment clones had higher values of RWC, leaf proline content, narrower width and length of stomata openings, but smaller value of WSD compared to susceptible clones. Meanwhile, the character of leaf thickness might not significanly different to the character of drought tolerance.

No abstract

Currently, vascular streak dieback (VSD) attacks have widespread in areas of the center of cocoa (Theobroma cacao L.) production, especially in Sulawesi. Salicylic acid and benzoic acid are part of phenol compounds reportedly acts as bioimmunoregulator in increasing of plant resistance to that pathogen. The objective of this research was to investigate effect of exogenous salicylic acid and benzoic acid applications to VSD disease attack on cocoa seedlings. The research was conducted at Indonesian Coffee and Cocoa Research Institute, Jember, East Java. This experiment designed using randomized completely block design with three replications. The treatments included concentrations of salicylic acid in 0.5 mMol, 1 mMol, 2 mMol; benzoic acid with concentration 0.5 mMol, 1 mMol, 2 mMol; and control (water spray). Observations were based on the incidence and severity damage of disease, plant height, stem diameter, number of leaves, stelate trichome, chlorophyll, width and length of stomatal apperture, and number of stomata. Exogenous salicylic acid and benzoic acid as phytohormone can reduce disease insidence and severity of VSD. In conclusion, our results indicated that exogenous salicylic acid and benzoic promoted stomatal closure in cocoa leaf by decreasing width-stomatal closure. Salicylic and benzoic acid had no effect to plant height, stem diameter, number of leaves, length of stomatal apperture, number of stomata, and number of stelate trichome.