Stem growth characteristics of high yielding Miscanthus correlate with yield, development and intraspecific competition within plots

Type Article
Original languageEnglish
Pages (from-to)1075-1085
Number of pages11
JournalGCB Bioenergy
Volume11
Issue number9
Early online date03 Mar 2019
DOI
Publication statusPublished - 01 Sep 2019
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Abstract

High yielding perennial grasses are utilised 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 utilised high yielding commercial genotypes growing in plots the conclusions are likely more commercially relevant.
Stem elongation was measured from five high yielding genotypes, 10 plants per plot from twenty 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 parameterised 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 rate had shorter duration 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 three years and growth parameterised 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 parameterised using temperature and only in Mxg suggesting different limitations to growth were exerted on the two genotypes. The different limitations to seasonal growth 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 maximise seasonal yield in perennial biomass crops.

Keywords

  • bioenergy, energy crops, growth curves, Miscanthus, modelling, yield