Analisis keragaman dan stabilitas genetik temulawak (Curcuma xanthorrhiza Roxb.) Indonesia

This study consists of two experiments. The first was multilocations test in dryland and the second was multiseasons test under two sunlight intensities (45% and 100%). Fourteen temulawak (Curcuma xanthorrhiza Roxb.) accessions were used in both experiments. The first experiment was conducted to determine genetic parameters in two locations (Serpong and Bogor) from December 2006 to August 2007. Direct and indirect effects of vegetative components to rhizome fresh weight through path analysis were also investigated. The observed traits in this experiment consist of vegetative, yield and secondary metabolite components. The second experiment was conducted to determine genetic parameters, genetic stability and path analysis under two sunlight intensities for three seasons (October 2004 to August 2007). Grouping of accessions tolerancy to different sunlight intensities was also investigated. The observed traits consist of vegetative and yield components.
There were no differences among tested accessions based on the analysis of variance in the multilocations experiment, except for tiller number and leaf length/width ratio. The heritability of these traits were high (h2 bs=73.7% and h2 bs=61.8%, respectively). However, their genetic variabilities were narrow (σ 2 g < 2 σσ 2 g). Differences among tested accessions in two sunlight intensities showed by 8 traits in the first season, 2 traits in the second season and 1 trait in the third season. High heritability and wide genetic variability showed by leaf length, plant height and leaf length/width ratio.
Full sunlight intensity tolerant accessions were T12 (Imogiri-Yogyakarta), T4 (Majenang-Central Java), T11 (Gunung Kidul-Yogyakarta) and T7 (Majalengka-West Java). Shading (sunlight intensity 45%) tolerant accessions were T11, T16 (Pasir Gaok 3-West Java), T4 and T12. Accessions T11 and T16 were stabil (bi= 1.0) in various conditions under 45% sunlight intensity while T4 and T12 were stabil under optimum condition (bi< 1.0) based on Finlay Wilkinson stability test. Those accessions showed high rhizome fresh weight (above their yield mean µ> 391.4 g/plant).
The correlation between vegetative traits and rhizome fresh weight were also analyzed. Tiller number could be used as selection criteria for rhizome fresh weight in dryland under full sunlight, while leaf width could be used in shaded area. These traits were chosen as selection criteria because of their high heritability (h2 bs-tiller number= 73.7%, h2 bs-leaf width = 54.2%), high direct effect (P tiller number= 0.64, P leaf width = 2.27) and high significant correlation with rhizome fresh weight (r tiller number = 0.89, r leaf width = 0.90).