Mating system and inbreeding depression in whitebark pine (Pinus albicaulis Engelm.)
Mating system and inbreeding depression in whitebark pine (Pinus albicaulis Engelm.)
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DOI：
10.1007/s11295-007-0082-4
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发表时间：
2007-10-01
影响因子：
2.4
通讯作者：
Aitken, Sally N.
中科院分区：
文献类型：
--
作者：
Bower, Andrew D.;Aitken, Sally N.
利用同工酶和幼苗普通园林实验确定了白皮松（Pinus albicaulis Engelm.）数量性状的交配系统和近交抑制。对来自三个不同地理区域（俄勒冈州、蒙大拿州和不列颠哥伦比亚省南部）的科后代阵列的胚胎和单倍体大配子体进行同步同工酶分析，用于估计亲本和后代近交系数，以及区域和科平均多位点异交率（t（m））。在普通花园实验中，在两种温度处理下生长的同一科幼苗的数量性状家族平均值根据估计的近交系数进行回归，以确定近交抑制的存在和程度。 t(m) 的区域估计值范围为 0.73 至 0.93，所有区域的平均值为 0.86。家族平均 t(m) 值表明异交占主导地位；然而，有些人经历了严重的近亲繁殖。相对于哈迪-温伯格平衡，俄勒冈地区的亲本代杂合子显着过剩，而俄勒冈州和不列颠哥伦比亚省南部地区的后代杂合子缺乏，表明对近交个体的选择。 BC省南部地区环境温度处理下的生物量是唯一与近交系数显着相关的性状。该区域的平均近交系数为0.25，根据这种关系，如果不通过选择去除近交个体，该区域的平均预测生物量将减少19.6%。据估计，白皮松的异交率略低于大多数风授粉针叶树，虽然大多数个体都是高度异交，但有些个体经历了大量的近交。
Mating system and inbreeding depression in quantitative traits of whitebark pine (Pinus albicaulis Engelm.) was determined using isozymes and a seedling common garden experiment. Simultaneous isozyme analysis of embryo and haploid megagametophyes from progeny arrays of families in three distinct geographic regions (Oregon, Montana, and southern British Columbia) was used to estimate parental and progeny inbreeding coefficients, as well as regional and family mean multilocus outcrossing rates (t(m)). Quantitative trait family means of seedlings from the same families growing in two temperature treatments in a common garden experiment were regressed on the estimated inbreeding coefficient to determine the presence and magnitude of inbreeding depression. Regional estimates of t(m) ranged from 0.73 to 0.93, with a mean over all regions of 0.86. Family mean t(m) values indicated predominant outcrossing; however, some individuals experienced substantial inbreeding. The Oregon region had a significant excess of heterozygotes in the parental generation relative to Hardy-Weinberg equilibrium, while both the Oregon and southern BC regions had a heterozygote deficiency in progeny, suggesting selection against inbred individuals. Biomass in the ambient temperature treatment for the southern BC region was the only trait significantly related to inbreeding coefficient. The mean inbreeding coefficient for this region was 0.25, and based on this relationship, mean predicted biomass would be reduced by 19.6% in this region if inbred individuals are not removed by selection. The estimated outcrossing rate of whitebark pine is slightly lower than most wind-pollinated conifers, and while most individuals are highly outcrossing, some experience substantial inbreeding.