Indication of Xenia Effect on Cocoa (Theobroma Cacao L.)

Cocoa plant generally is classified as cross pollinated plant and self-incompatible plant, then there is indication the presence of pollen influence on cocoa bean quality. This study was aimed to determine the effect of pollen sources (xenia) on the colour and size characters of fresh cocoa beans (Theobroma cacao L.). This study was done on two stages. The first stage, a treatment of hand pollination of cocoa clones of DR 1, DR 2, DRC 16, KW 264 and ICCRI 03 was applied in this study. There were five treatments of hand pollination: DR 2 x DR 1, DRC 16 x DR 1, DRC 16 X KW 264, DR 1 x DR 2 and ICCRI 03 x DRC 16. Each treatment was repeated four times. Colour parameters of fresh cocoa beans were observed. The second stage consisted of nine hand pollination combinations: TSH 858 x Sulawesi 1, TSH 858 x ICCRI 03, TSH 858 x KW 264, TSH 858 x KW 570, TSH 858 x Sca 6, Sulawesi 1 x TSH 858, Sulawesi 1 x Sca 6, Sulawesi 1 x KW 570 and KW 516 x Sca 6. Each treatment was repeated three times. Size parameters of fresh cocoa pod and beans were observed. The result showed that hybridization using pollen source from bulk cocoa and DR 1 contributed dark colour to fineflavored cocoa. This colour contribution was showed by the increase in the dark fresh percentage of cocoa beans. On the other hand, hybridization using pollen source from fine-flavored cocoa contributed white and pale colour to bulk cocoa. This light colour contribution was showed by the decrease in the percentage of the dark fresh beans. Xenia effect occured on pod weight, pod length, pod girth, bean weight with pulp per pod and bean weight without pulp per pod which was shown by the hybridization with TSH 858 as female parent and weight bean without pulp per pod shown by the hybridization with THS 858 and Sulawesi 1 as female parent

The Resistance of Cocoa Hybrids to Vascular-streak Dieback

Breeding for VSD resistance on cocoa was carried out by inter-crossing the selected clones of TSH 858, KW 162, KW 163, KW 165, KEE 2, ICS 13 and NIC 7 which were selected based on the criteria of VSD resistance, productivity and cross-compatibility. This research has objective to evaluate hybrids of the crossess for VSD resistance, inheritance of the resistance and selecting the most valuable parental-clones for further crossess. Fourteen hybrids and one control were tested 14 in the randomized-completely block design with 4 blocks where in each plot 16 trees planted at Kaliwining Experimental Station in Jember. The resistance was evaluated in the field by scoring the symptoms in the range of 0—6 at 7 year after planting. The scores were varied significantly among the hybrids in the range of 2.19—4.53. Hybrids which were generated from the crosses of resistant clones performed lower number of the score than the hybrids generated from crosses between two susceptible clones (TSH 858 x NIC 7) which performed highest score. The hybrids classified as resistant were TSH 858 x KW 162 (F1 and reciprocal), KW 162 x KEE 2 (F1 and reciprocal), KW 162 x ICS 13, KW 165 x KEE 2. Of the parental clones, KW 162 is the most promising parent as lower score obtained when used it as male or female compared to KEE 2 which performed quite similar of the score with TSH 858 as susceptible parent. Therefore, it could be supposed that KW 162 has better combining ability than KEE 2 where these resistant-clones showed different segregation of their resistance. The resistance was segregated by KW 162 in term of ratio 15 resistant : 1 susceptible while KEE 2 the ratio 1 resistant: 1 susceptible

Intensity of Vascular Streak Dieback in Different Cocoa Clones and Various Agro-climatic Conditions

Vascular streak dieback (VSD) is one of the main diseases on cocoa. This disease can produce a heavy damage in susceptible plants. Agro-climatic condition influences the VSD disease severity level. A study on the relationship between agro-climatic condition and VSD disease severity was conducted in eight locations which were selected based on difference in agro-climatic conditions including altitude, rainfall, number of wet, and dry months. Randomized complete block design was used consisting of eight agro-climatic conditions as treatments which consisted of 200 trees samples, and scored for VSD intensity. A study was also conducted on the response of cocoa clones with different level of resistance at different altitude at Kendeng Lembu, Jatirono, Sungai Lembu, Banjarsari, and Sumber Asin Plantations. A split plot design was applied consisting of two factors. The first factor was location including Pager Gunung (highland) and Besaran (lowland). The second factor was clone resistance with two levels: PA 191 (resistant) and BL 703 (susceptible). VSD scores and stomatal characteristics (stomata number, stomata diameter, and stomata aperture) were determined. The results of experiment showed that VSD scoring differed significantly between the eight agro-climatic conditions. The highest VSD score occurred in the lowland (Gereng Rejo, Banjarsari Plantation, 38 m asl.), where the average annual rainfall was 2161 mm, with five dry months. Cocoa trees in Sumber Asin (580 m asl.), with the average annual rainfall of 2302 mm and 8.5 wet months/3.5 dry months were mostly free of VSD disease. Altitude was positively correlated with rainfall, and negatively correlated with VSD severity. Number of wet months was negatively correlated with VSD severity. Conversely, number of dry months was positively correlated with VSD. The result indicated that genotype, environment, or their interaction did not significantly affect number and aperture of stomata. Although stomatal diameter was significantly affected by environment, genotypes or their interaction with environment did not influence this character