Fertility variation in Milletia stuhlmannii, Brachystegia bohemii and Laucaena leucocephala and its effects on relatedness in seeds
1998
Bila, A.D. (Eduardo Mondlane Univ., Maputo (Mozambique). Department of Forestry Engineering) | Lindgren, D.
Variation in seed production was studied in five stands in Mozambique. It was possible to describe the distribution of seed set as a power function y = xa, where y is the accumulative seeds production, x is the ranked proportion of trees contributing and a a parameter that cannot be less than one. For the studied populations, a = 2.36, 2.45, 3.10, 4.12 and 4.72; this range seems to be in general agreement with data reported by other investigations. The parameter a increased with increasing variation in fertility within stands. The degree of relatedness expected in a seed crop could also be expressed with the status (effective) number relative to the number of investigated trees, that was 0.67, 0.65, 0.54, 0.43 and 0.38, respectively. The effect of collecting an equal amount of seeds per tree could be quantified, and it seems likely that this reduces the relatedness among seeds to a considerable degree and therefore is effective in maintaining diversity. It is recommended to utilize this effect when establishing stands for gene conservation purposes. Formulae for a fertility estimate was derived and the required number of fertility observations was discussed
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