Abstract
The cultivation of Miscanthus has attracted growing interest despite its yield instability. Therefore, understanding what causes such instability is of primary interest for breeding. Our objectives were to estimate the genetic parameters—genetic variance and genetic heritability—and genetic correlations for flowering time-related traits in a biparental Miscanthus sinensis diploid population, and divide the year effect into age and growing season effects using a staggered-start design. The population was established with single plants organized with this design and consisted of two genotype groups established twice in a same field, in 2014 and 2015, with a total of 159 genotypes and 82 common genotypes between the groups. Soil conditions being identical between both stands, the growing season conditions corresponded to climatic conditions. All plants were extensively phenotyped for different panicle and anther emergence traits in 2018 and 2019. All traits were delayed by 3 weeks in 2019 compared to 2018, which was explained by climatic conditions that occurred before the floral transition, mainly a 3 °C decrease in temperatures. When dividing the year effect, the genotype × growing season interaction was much higher than the genotype × age interaction. This increased the genotype × growing season interaction variance compared to the genotype × age interaction variance: the growing season effect decreased the genetic parameters for all flowering time-related traits, up to 20% for broad-sense heritability. Interestingly, most traits responded similarly to this effect. Therefore, M. sinensis breeding for flowering time must be conducted under contrasted climatic conditions to select more stable genotypes.
Highlights
IntroductionGabrielle et al [1] reported that a small proportion of European renewable energy is derived from dedicated bioenergy crops
Biomass is expected to play a major role in the energy transition, which involves switching to a safe and sustainable lowcarbon economy, in order to address the growing challenges due to depleting fossil resources and climate change [1]
The discussion focused on three points: 1) the flowering time delay may be explained by climatic conditions that occurred before the floral transition, 2) the genotype × climate variances were greater than the genotype × age variances for all flowering-time related traits, which implied a decrease in heritability and, 3) the existence of these previously significant effects of the climate, most flowering-time related traits of the population behaved to changes in climatic conditions
Summary
Gabrielle et al [1] reported that a small proportion of European renewable energy is derived from dedicated bioenergy crops. Miscanthus is a perennial C4 rhizomatous grass originating from eastern and southern Asia [3]. × giganteus is sterile and presents genetic uniformity. This crop currently relies on a single clone, which may cause risks that have been recognized in case of disease, pest, or climate pressure [9]. As early as 1997, Greef et al [10] reported that genetic diversity was very low within a pool of 31 European M. Concluded that 27 American and 6 European accessions were derived from a single clone by vegetative propagation. M. sinensis exhibits huge genetic variability, with major genetic groups originating from Asia [3, 12, 13], which offers numerous opportunities to enlarge the varietal offer
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