Richardson Bryce A, Germino Matthew J, Warwell Marcus V, Buerki Sven
USDA Forest Service, Rocky Mountain Research Station, Moscow, ID, USA.
U.S. Geological Survey, Forest and Rangeland Ecosystem Service Center, Boise, ID, USA.
Am J Bot. 2021 Aug;108(8):1405-1416. doi: 10.1002/ajb2.1714. Epub 2021 Aug 30.
Adaptive traits can be dramatically altered by genome duplication. The study of interactions among traits, ploidy, and the environment are necessary to develop an understanding of how polyploidy affects niche differentiation and to develop restoration strategies for resilient native ecosystems.
Growth and fecundity were measured in common gardens for 39 populations of big sagebrush (Artemisia tridentata) containing two subspecies and two ploidy levels. General linear mixed-effect models assessed how much of the trait variation could be attributed to genetics (i.e., ploidy and climatic adaptation), environment, and gene-environment interactions.
Growth and fecundity variation were explained well by the mixed models (80% and 91%, respectively). Much of the trait variation was attributed to environment, and 15% of variation in growth and 34% of variation in seed yield were attributed to genetics. Genetic trait variation was mostly attributable to ploidy, with much higher growth and seed production in diploids, even in a warm-dry environment typically dominated by tetraploids. Population-level genetic variation was also evident and was related to the climate of each population's origin.
Ploidy is a strong predictor growth and seed yield, regardless of common-garden environment. The superior growth and fecundity of diploids across environments raises the question as to how tetraploids can be more prevalent than diploids, especially in warm-dry environments. Two hypotheses that may explain the abundance of tetraploids on the landscape include selection for drought resistance at the seedling stage, and greater competitive ability in water uptake in the upper soil horizon.
基因组复制可显著改变适应性性状。研究性状、倍性和环境之间的相互作用，对于理解多倍体如何影响生态位分化以及制定恢复有弹性的本地生态系统的策略是必要的。
在共同园圃中对包含两个亚种和两个倍性水平的39个大艾草（三齿蒿）种群的生长和繁殖力进行了测量。通用线性混合效应模型评估了性状变异中有多少可归因于遗传学（即倍性和气候适应性）、环境以及基因 - 环境相互作用。
混合模型很好地解释了生长和繁殖力变异（分别为80%和91%）。大部分性状变异归因于环境，生长变异的15%和种子产量变异的34%归因于遗传学。遗传性状变异大多归因于倍性，即使在通常以四倍体为主的温暖干燥环境中，二倍体的生长和种子产量也高得多。种群水平的遗传变异也很明显，并且与每个种群起源地的气候有关。
无论共同园圃环境如何，倍性都是生长和种子产量的有力预测指标。二倍体在各种环境中都具有优越的生长和繁殖力，这就提出了一个问题，即四倍体如何能比二倍体更普遍，尤其是在温暖干燥的环境中。两个可能解释景观中四倍体丰富的假说是：在幼苗阶段对抗旱性的选择，以及在上层土壤层中更强的水分吸收竞争能力。
