High yielding perennial grasses are utilized as biomass for the bioeconomy and to displace fossil fuels. Many such grasses, including Miscanthus, are largely undomesticated. The main Miscanthus crop is a naturally occurring hydrid M. × giganteus (Mxg). All above ground biomass from Miscanthus is harvested. Stem traits correlate strongly with yield and therefore understanding the seasonal progression of stem growth should identify routes for improved yield. If such studies utilized high yielding commercial genotypes growing in plots the conclusions are likely to be more commercially relevant. Stem elongation was measured from five high yielding genotypes, 10 plants per plot from 20 plots in a replicated field trial over 4 years. Richards growth function produced an accurate fit to stem elongation. Differentials, double differentials and integrals of the parameterized function produced six growth characteristics, describing growth rate, timing and duration of the logarithmic growth phase and area under the growth curve. Maximum growth rate was correlated with yield and compensatory interactions were identified, for example plants with higher maximal growth rates had shorter durations of logarithmic growth. Plant position within plots of lower yielding genotypes did not affect growth characteristics but had a significant effect on late season growth characteristics in higher yielding genotypes. Two high yielding genotypes were compared over 3 years and growth parameterized using four different factors. The inverse correlation between maximum growth rate and duration of logarithmic growth was consistent across years and factors in both genotypes except when parameterized using temperature and only in Mxg. This suggested that different limitations to growth were exerted on the two genotypes which may help explain the exceptional performance of the Mxg genotype. We discuss the implications of the identified complex interactions in growth characteristics for approaches to maximize seasonal yield in perennial biomass crops.

中文翻译：

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高产芒草的茎生长特征与小区内的产量、发育和种内竞争相关。

高产多年生草被用作生物经济的生物质并取代化石燃料。许多这样的草，包括芒草，基本上都没有被驯化。主要芒草作物是天然存在的杂种芒草(M. × giganteus ) ( Mxg )。收获来自芒草的所有地上生物量。茎性状与产量密切相关，因此了解茎生长的季节进程应该确定提高产量的途径。如果此类研究利用了在地块中生长的高产商业基因型，那么结论可能更具商业相关性。茎伸长是通过 4 年的重复田间试验中的 20 个地块中的 5 个高产基因型（每个地块 10 株植物）来测量的。理查兹生长函数与茎伸长精确拟合。参数化函数的微分、二重微分和积分产生了六个生长特征，描述了生长速率、对数生长阶段的时间和持续时间以及生长曲线下的面积。最大生长速率与产量相关，并确定了补偿性相互作用，例如最大生长速率较高的植物的对数生长持续时间较短。低产基因型地块内的植物位置不影响生长特性，但对高产基因型的晚季生长特性有显着影响。对两种高产基因型进行了 3 年的比较，并使用四种不同的因素对生长进行参数化。最大增长率和对数生长持续时间之间的负相关在两种基因型的年份和因素中是一致的，除了使用温度参数化且仅在Mxg中时除外。这表明两种基因型对生长施加了不同的限制，这可能有助于解释Mxg基因型的特殊性能。我们讨论了已确定的生长特征中复杂的相互作用对于最大化多年生生物质作物季节性产量的方法的影响。