Department of Forest Science, University of Alberta, Edmonton, Alberta, Canada T6G 2H1.
Genetics. 1985 Mar;109(3):569-84. doi: 10.1093/genetics/109.3.569.
Mating system parameters of a northern conifer, Pinus banksiana Lamb., were estimated from allozyme polymorphisms. Seeds analyzed were obtained from serotinous cones of 30 individuals and represented four independent fertilizations in 1975, 1976, 1977 and 1978. Results indicated that a mixed mating system model, with a mean effective outcrossing rate of 88 +/- 0.047%, described the mating system of this stand. However, there was an approximately linear increase in the apparent selfing rate from the oldest (1975) to the newest (1978) crop. Two hypotheses could account for these observations. First, there may have been changes in the mating system during the 4-yr period, but linearity of the differences observed in this study may have been due to chance. These changes were, however, independent of the variability of the observed pollen pool. This indicated that they were not a result of different proportions of outcrossed zygotes directly observed. Second, there could have been a more or less constant amount of selfing, followed by a differential loss of viability of selfed and outcrossed zygotes during the period of storage in the cones. Under this hypothesis, selfed zygotes are at a selective disadvantage relative to outcrossed zygotes. No differences in the mating system could be demonstrated among the three crown strata of this stand. There was significant interlocus heterogeneity in the filial generation genotypic distributions and in the estimated outcrossing rates, reflecting the complex nature of forces that can affect single-locus estimates. There was evidence of some additional inbreeding, possibly due to family structures in the stand; however, this was a minor component of the total inbreeding.
利用等位酶多态性估计了北方针叶树——黑云杉（PinusbanksianaLamb.）的交配系统参数。分析的种子来自 30 个个体的晚熟球果，代表了 1975 年、1976 年、1977 年和 1978 年的 4 次独立受精。结果表明，一个混合交配系统模型，平均有效异交率为 88 +/- 0.047%，描述了该林分的交配系统。然而，自交率从最老（1975 年）到最新（1978 年）的作物呈近似线性增加。有两个假设可以解释这些观察结果。首先，在 4 年期间交配系统可能发生了变化，但本研究中观察到的差异的线性可能是偶然的。这些变化与观察到的花粉库的可变性无关。这表明它们不是由于直接观察到的异交合子的比例不同而产生的。其次，可能存在或多或少恒定的自交量，然后在球果中储存期间，自交和异交合子的活力有差异损失。根据这个假设，自交合子相对于异交合子处于选择劣势。在这个林分的三个树冠层中，交配系统没有差异。在后代代基因型分布和估计的异交率中，存在着座位间的异质性，反映了影响单座位估计的复杂力量。有证据表明存在一些额外的近亲繁殖，可能是由于林分中的家族结构造成的；然而，这只是总近亲繁殖的一小部分。
