Assessment of bud-grafting and side-grafting techniques to support

Introduction

Cocoa development programing Indonesia are confront with various obstacles such as less of crop productivity, increasing population of old plants and poorly maintained crops, the presence of various pests or diseases, low seedling quality, undeveloped of downstream domestic industry, and the difficulty for farmers to get special funding for cocoa development program (Directorate General of Estate Crops, 2012).

Base on background of the above issues, in order to improve the productivity and quality of national cocoa, the National Cocoa Movement (NCM) program was established. This activity was initiated in 2009 with Rp. 302 billion and it was allocated for 11 regencyie. Luwu Utara, Luwu Timur, Luwu, Enrekang, Soppeng, Sidrap, Wajo, Soppeng, Bone, Bantaeng and Bulukumba. This program undertakes the rejuvenation, rehabilitation and intensification of cocoa development area of 48,200 ha consisting of 4,300 ha for rejuvenation, 20,900 ha for rehabilitation activities and 23,700 ha for intensification (Harian Fajar, in Limbongan et al., 2012). 

Lack of seedlings become obstacles in the cocoa plantation revitalization program, in 2010 the revitalization requires cocoa seeds up to 75 million seedlings to support the development of an area of 200,000 ha, but the availability of seedlings is only 57 million (Indonesian Plantation Research Institute, 2008). In the nature, T. cocoa multiplies via cross pollination. The seeds usually have many genetic backgrounds which may obtain crops that may be very different from each other ergonomically. In the other hand, reproductions by cloned graft materials tend to show bushy pattern which in a disadvantage. (Ramirez et al., 2017) 

SE technology can provide seedlings in large quantities, relatively faster available, and produce identical plant genetic with the parent and normally morphology. The somatic embryogenesis plant has a perfect crown, tap root, complete vigor, and is capable to producing faster and productive, and droughttolerance (Winarsih et al., 2002). During the NCM program, SE seedlings distribution data from 2009 to 2012 in South Sulawesi reached a total of 15,150,000 and recorded as follows 2009: 4.3 million seedlings; 2010: 3.55 million seedlings; 2011: 6.3 million seedlings, and 2012: 1.0 million seedlings (Anonymous, 2012). 

The efficacy and success of SE seedlings production in the laboratory is quite widely reported. However, some research resulted in the weakness of SE seedlings in the field. Approximately 70-80% of farmers in Luwu and Luwu Utara consider cocoa plants from SE were less adaptive in the field (Limbongan et al., 2011). Further study Limbongan et al. (2012) suggests that up to the third year, the percentage of cocoa plants from SE were decreasing. Center for Research and Natural Resource Development, Hasanuddin University, said that 74% of cocoa rejuvenation areas using SE seedlings in South Sulawesi and West Sulawesi are damaged, only 26% are found to be growth but in unhealthy conditions (Anonymous, 2012).

The government plan to evaluate the use of Somatik Embryogenesis (SE) cacao seedlings (Sinar Tani, 2014). The reason is that since three years of the National Movement of Cocoa Production and Quality Improvement NCM program, SE cocoa seedlings have not shown any increase in productivity. Through this study is expected to apply the technology of bud grafting and side grafting for somatic embryogenesis (SE) cocoa which has less of growth and yield.