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Abstract
A study on nursery selection in Hevea breeding
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 RRIM 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 found to correlate with the mature yield
included NY, NY/NG, LVD and PI. The three correlated characters (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.
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