000			01330nam a2200145Ia 4500
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100			_aSimmonds N W
245		0	_aTheoretical aspects of synthetic/polycross populations of rubber seedlings
260			_bJournal of Natural Rubber Research _c1986
300			_a15-Jan
520			_aRubber seedlings, the product of seed gardens, have been grown successfully for decades. Such populations are polycrosses or first generation synthetic varieties (SYN1). The genetics of SYN1 in rubber have not been investigated but some (rather speculative) calculations are possible of fragmentary data. It is likely: that parents are unequally represented among progeny; that crossing is very imperfect but that the deleterious effects of inbreeding are partly mitigated by seedling culling; that, nevertheless, SYN1 suffers from some inbreeding depression; that second generation seedlings (SYN2) offer interesting practical potential worthy of investigation; and that seed-garden design deserves far more attention that it has had. Suggestions for relevant experiments are made and it is pointed out that isozyme genes would offer a powerful method of analysing the genetical dynamics of seed gardens and their products.
650			_aRubber seedlings
650			_aSeed gardens
942			_cJS
999			_c71181 _d71181