The perennial grass species that are being developed as biomass feedstock crops harbor extensive genotypic diversity, but the effects of this diversity on biomass production are not well understood. We investigated the effects of genotypic diversity in switchgrass (Panicum virgatum) and big bluestem (Andropogon gerardii) on perennial biomass cropping systems in two experiments conducted over 2008–2014 at a 5.4‐ha fertile field site in northeastern Illinois, USA. We varied levels of switchgrass and big bluestem genotypic diversity using various local and nonlocal cultivars – under low or high species diversity, with or without nitrogen inputs – and quantified establishment, biomass yield, and biomass composition. In one experiment (‘agronomic trial’), we compared three switchgrass cultivars in monoculture to a switchgrass cultivar mixture and three different species mixtures, with or without N fertilization. In another experiment (‘diversity gradient’), we varied diversity levels in switchgrass and big bluestem (1, 2, 4, or 6 cultivars per plot), with one or two species per plot. In both experiments, cultivar mixtures produced yields equivalent to or greater than the best cultivars. In the agronomic trial, the three switchgrass mixture showed the highest production overall, though not significantly different than best cultivar monoculture. In the diversity gradient, genotypic mixtures had one‐third higher biomass production than the average monoculture, and none of the monocultures were significantly higher yielding than the average mixture. Year‐to‐year variation in yields was lowest in the three‐cultivar switchgrass mixtures and Cave‐In‐Rock (the southern Illinois cultivar) and also reduced in the mixture of switchgrass and big bluestem relative to the species monocultures. The effects of genotypic diversity on biomass composition were modest relative to the differences among species and genotypes. Our findings suggest that local genotypes can be included in biomass cropping systems without compromising yields and that genotypic mixtures could help provide high, stable yields of high‐quality biomass feedstocks.

中文翻译：

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基因型多样性对本地多年生生物能源种植系统中生物量生产的影响。


正在开发作为生物质原料作物的多年生草种具有广泛的基因型多样性，但这种多样性对生物质生产的影响尚不清楚。我们于 2008 年至 2014 年在美国伊利诺伊州东北部的 5.4 公顷肥沃田地进行了两项实验，研究了柳枝稷 ( Panicum virgatum ) 和大须芒草 ( Andropogon gerardii ) 的基因型多样性对多年生生物量种植系统的影响。我们使用各种本地和非本地品种（在低或高物种多样性下，有或没有氮输入）改变了柳枝稷和大须芒草基因型多样性的水平，并量化了建立、生物量产量和生物量组成。在一项实验（“农艺试验”）中，我们将单一栽培的三种柳枝稷品种与柳枝稷品种混合物和三种不同物种的混合物进行了比较，无论是否施氮肥。在另一项实验（“多样性梯度”）中，我们改变了柳枝稷和大须芒草的多样性水平（每个地块 1、2、4 或 6 个品种），每个地块有一个或两个物种。在这两个实验中，品种混合物的产量等于或高于最佳品种。在农艺试验中，三种柳枝稷混合物显示出总体最高产量，尽管与最佳品种单一栽培没有显着差异。在多样性梯度中，基因型混合物的生物量产量比平均单一栽培高出三分之一，并且没有任何单一栽培的产量显着高于平均混合物。 与单一栽培品种相比，三品种柳枝稷混合物和 Cave-In-Rock（伊利诺伊州南部品种）的产量逐年变化最低，柳枝稷和大须芒草混合物的产量也有所减少。相对于物种和基因型之间的差异，基因型多样性对生物量组成的影响是适度的。我们的研究结果表明，本地基因型可以纳入生物质种植系统而不影响产量，并且基因型混合物可以帮助提供高产、稳定的优质生物质原料。