Physiological bases of cultivar differences in average grain weight in wheat: scaling down from plot to individual grain in elite material
In recent decades, wheat grain yields have been increased mainly through increases in grain number per m2 (GNM2) rather than through increases in average grain weight (AGW). Using AGW as a lever to increase yield would require avoidance of the negative relationship existing between GNM2 and AGW. It...
| Autores: | , , , , |
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| Tipo de documento: | artigo |
| Estado: | Versión aceptada para publicación |
| Data de publicação: | 2022 |
| País: | España |
| Recursos: | Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya) |
| Repositório: | Recercat. Dipósit de la Recerca de Catalunya |
| OAI Identifier: | oai:recercat.cat:10459.1/84568 |
| Acesso em linha: | https://doi.org/10.1016/j.fcr.2022.108713 http://hdl.handle.net/10459.1/84568 |
| Access Level: | Acceso aberto |
| Palavra-chave: | Cereals Blat Wheat |
| Resumo: | In recent decades, wheat grain yields have been increased mainly through increases in grain number per m2 (GNM2) rather than through increases in average grain weight (AGW). Using AGW as a lever to increase yield would require avoidance of the negative relationship existing between GNM2 and AGW. It is generally proposed that this trade-off originates from an increase in the proportion of small grains with high GNM2 caused either by an increase in the proportion of secondary tillers in the spike populations or by an increase of the proportion of grains located in distal positions within individual spikes. These two important populational effects could mask true genotypic differences in AGW. The existence of these constitutive differences has already been proposed, but without considering the full extent of the populational confounding effects. Identifying the part of the constitutive genetic determinism of AGW, that is totally independent of GNM2, may contribute to increases in grain yield under future target environments. To address this question, the populational effects on AGW were analysed using four, modern, well-adapted bread wheat cultivars, showing similar grain yields but contrasting AGWs. The dissection of populational effects was conducted at three hierarchical levels: the plot, the spike and the single grain, and under two contrasting environmental conditions (well-watered vs water-deficit conditions). Regardless of the environment, no, or only slight, differences in individual spike size between cultivars were observed. Taken together with the weak relationship between spike size and AGW, it demonstrates that AGW differences between cultivars cannot be attributed to populational effects at the spike level. Moreover, the analysis of individual grain mass distributions, showed that the differences in AGW between cultivars, originate from shifts of the whole distribution rather that from modifications in distribution shape. This result clearly shows that AGW differences between cultivar cannot be attributed to populational effect at the individual grain level. The analysis performed at both the spike and individual grain scales indicates that AGW differences between cultivar are largely constitutive and that an increase in grain yield through AGW can be considered independently from the trade-off between GNM2 and AGW and offers new perspectives for wheat genetic improvement. |
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