Evidence for divergence of response in Indica, Japonica, and wild rice to high CO₂ × temperature interaction

Abstract

High CO2 and high temperature have an antagonistic interaction effect on rice yield potential and present a unique challenge to adapting rice to projected future climates. Understanding how the differences in response to these two abiotic variables are partitioned across rice germplasm accessions may be key to identifying potentially useful sources of resilient alleles for adapting rice to climate change. In this study, we evaluated eleven globally diverse rice accessions under controlled conditions at two carbon dioxide concentrations (400 and 600 ppm) and four temperature environments (29 °C day/21 °C night; 29 °C day/21 °C night with additional heat stress at anthesis; 34 °C day/26 °C night; and 34 °C day/26 °C night with additional heat stress at anthesis) for a suite of traits including five yield components, five growth characteristics, one phenological trait, and four photosynthesis-related measurements. Multivariate analyses of mean trait data from these eight treatments divide our rice panel into two primary groups consistent with the genetic classification of INDICA/INDICA-like and JAPONICA populations. Overall, we find that the productivity of plants grown under elevated [CO2 ] was more sensitive (negative response) to high temperature stress compared with that of plants grown under ambient [CO2 ] across this diversity panel. We report differential response to CO2 × temperature interaction for INDICA/INDICA-like and JAPONICA rice accessions and find preliminary evidence for the beneficial introduction of exotic alleles into cultivated rice genomic background. Overall, these results support the idea of using wild or currently unadapted gene pools in rice to enhance breeding efforts to secure future climate change adaptation.

High temperature stress during flowering and grain filling offsets beneficial impact of elevated CO2 on assimilate partitioning and sink-strength in rice

“…As indicated earlier, future climatic scenarios with e[CO 2 ] accompanied by higher temperature presents a unique challenge for crop improvement due to antagonistic interaction of these factors 31 , 32 . Despite higher growth and yield, e[CO 2 ] grown plants could be more sensitive to higher temperatures due to reduced stomatal conductance and transpiration under e[CO 2 ] 31 , 61 (Fig. 1 ; Supplementary Fig.…”

“…For example heat stress resulted in reduced grain weight or grain starch content even with higher sucrose supply from source tissue under e[CO 2 ] in rice 29 , 30 . Recent studies reveal that rice plants grown under e[CO 2 ] were more sensitive to heat stress compared to plants grown under ambient conditions 31 . Alternatively e[CO 2 ] failed to compensate for the negative impact of heat stress on yield 32 suggesting temperature to be the major driver inducing damage under e[CO 2 ] + HT interaction.…”

“…Negative impact of temperature documented on sink size and sink activity/strength (ability to utilize enhanced assimilate supply) in crop plants has instigated the need to explore crop responses to e[CO 2 ] + HT interaction under realistic environmental conditions. Previous studies quantifying e[CO 2 ] + HT interaction in rice are mostly conducted under controlled chamber conditions 15 , 27 , 29 – 31 which would not translate into delineating crop responses under realistic field conditions, due to limitation in space, light etc 33 .…”

Robust phenotyping strategies for evaluation of stem non-structural carbohydrates (NSC) in rice

“…However, long-term expectations should be tempered until effects of other climatic parameters (e.g. rising atmospheric CO 2 ) on pre-heading stem NSC are better understood, as they may have unexpected interaction effects (Moya et al , 1998; Baker, 2004; Ziska et al , 2014; Wang et al , 2016). …”

Early growth phase and caffeine content response to recent and projected increases in atmospheric carbon dioxide in coffee (Coffea arabica and C. canephora)

“…For example, studies have confirmed that there is significant intraspecific variation in the yield response to future CO 2 levels for cowpea (Vigna unguiculata (L.) Walp.) 7 ; common bean (Phaseolus vulgaris L.) 8 , rice (Oryza sativa L.) [9][10][11] ; wheat (Triticum aestivum L.) 12,13 and soybean (Glycine max (L.) Merr.) 14 , such that breeders could begin to select for CO 2 responsiveness among currently available germplasm.…”