A study on nursery selection in hevea breeding
1998
Tan, H. (No 27, Lengkok Zaaba, Taman Tun Dr. Ismail, 60000 Kuala Lumpur (Malaysia))
This paper describes a study on nursery selection carried out at the Rubber Research Institute of Malaysia. A sample of seedling progenies and their corresponding buddings (clones) of a family PB 5/51 x PRIM 600 was selected for this study. Nursery characters, namely nursery yield (NY), nursery yield per girth (NY/NG), nursery girth (NG), latex vessel density (LVD), plugging index (PI) and virgin bark thickness (VB), and mature yield over five years of tapping of the selected genotypes were investigated for their relationships and selection efficiencies. Among the nursery characters, NY was positively correlated with NY/NG and LVD but was negatively correlated with PI. NY/NG was correlated with LVD and PI but not with NG. NG was also found correlated with LVD and VB. There was no correlation detected between the yield parameters (NY and NY/NG) and VB. The nursery characters which were found to correlate with the mature yield included NY, NY/NG, LVD and PI. The three correlated characters (NY or NY/NG with LVD and PI) jointly accounted for 45 percent of the variations of the mature yield. Comparison of selections based on single or a combination of two and three nursery characters for mature yield sggested that NY or NY/NG would be adequate and practical to be adopted as early yield selection criteria. LVD and PI could enhance the selection efficiency when considered together with the above parameters marginally. However, considering the extra efforts, costs and manpower and facilities required for the measurement of these two additional characters and the marginal gains in the selection efficiency, these two additional selection parameters were only recommended for the refinement of selection for top-yielders. The implication of the findings are discussed in relation to the early selection strategy for Hevea improvement programme.
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