Abstract:

Mating systems in three populations of Masson pine (Pinus massonina Lamb.), including a clonal seed orchard, a plantation near the seed orchard and a clone bank were studied by isozyme analysis with the help of level starch gel electrophoresis. The results were as follows: the multi-locus estimate of outcrossing rate (t_m) of the seed orchard was 0.792 (se=0.062) (standard errors in parenthesis); the outcrossing rates (t_m) of clones in the central blocks and in the fringal blocks were 0.801 (se=0.075) and 0.800 (se=0.067), respectively; the estimate of t_m for the plantation near the seed orchard was 0.821 (se=0.188), while in the clone bank the t_m was 0.431 (se=0.131). It indicated that the outcrossing rates in this seed orchard were lower, which might be an important obstacle to increase the quantity and quality of seed. The paper discussed the main factors affecting the mating systems of populations. It analyzed the probable reasons for the low outcrossing rates of Masson pine and presented some suggestion for further studies in this area.

Key words: Pinus massoniana Lamb, Man-made population, Mating system