Selection of advanced polycross progenies in Hevea improvement.

摘要

This paper reviews progress made in the ortet (mother-tree) selection programme in Hevea improvement carried out at the Rubber Research Institute of Malaysia. Since the 1970s, a concerted search has been made for promising ortets from a population of 1.3 million seedlings derived from advanced polycross seed gardens, viz. PBIG and PBFP trials, in the commercial plantations of Peninsular Malaysia. Out of this sample, a total of 2613 genotypes (seedlings) were selected for further testing. Of 1289 genotypes tested in 3 field nurseries with 2 control clones, PR255 and RRIM600, 34.1% had mean yields equal to or higher than the former while 59.7% showed equal or higher yields than the latter. In the first series of the selection, which was tested in large scale clone trials, a number of ortet materials showed yield levels higher than the control RRIM600. Some of them had equal or higher mean yields than clones of the RRIM800 series and promotion plot clones in adjacent fields. These results imply thatselection of advanced polycross progenies (ortet selection) can be a useful complement to the normal hand (controlled) pollination programme in Hevea improvement.