Institute of Soil and Water Conservation, Northwest A & F University, Yangling, China.
Ottawa Research and development Centre (ORDC), Agriculture and Agri-Food Canada, Ottawa, Canada.
J Sci Food Agric. 2022 Jun;102(8):3336-3349. doi: 10.1002/jsfa.11680. Epub 2021 Dec 10.
Modern wheat cultivars have been developed having distinct advantages in many aspects under drought stress, such as plasticity in biomass allocation and root system architecture. A better understanding of the biomass allocation mechanisms that enable modern wheat to achieve higher yields and yield-based water use efficiency (WUE ) is essential for implementing best management strategies and identifying phenotypic traits for cultivar improvement. We systematically investigated the biomass allocation, morphological and physiological characteristics of three ploidy wheat genotypes under 80% and 50% field water-holding capacity (FC) conditions. Some crucial traits were also assessed in a complementary field experiment.
The diploid and tetraploid genotypes were found to allocate more biomass to the root system, especially roots in the topsoil under drought stress. Our data illustrated that lower WUE and yield of these old genotypes were due to excessive investment in the root system, which was associated with severely restricted canopy development. Modern hexaploid genotypes were found to allocate smaller biomass to roots and larger biomass to shoots. This not only ensured the necessary water uptake, but also allowed the plant to distribute more assimilates and limited water to the shoots. Therefore, the hexaploid genotypes have evolved a stable plant canopy structure to optimize WUE and grain yield.
This study demonstrated that the biomass shift from below ground to above ground or a more balanced root:shoot ratio tended to optimize water use and yield of the modern cultivars. This discovery provides potential guidance for future dryland wheat breeding and sustainable management strategies. © 2021 Her Majesty the Queen in Right of Canada Journal of The Science of Food and Agriculture © 2021 Society of Chemical Industry. Reproduced with the permission of the Minister of Agriculture and Agri-Food Canada.
现代小麦品种在干旱胁迫下具有许多方面的明显优势，例如生物量分配和根系结构的可塑性。更好地理解使现代小麦实现更高产量和基于产量的水分利用效率（WUE）的生物量分配机制，对于实施最佳管理策略和确定品种改良的表型特征至关重要。我们系统地研究了三个倍性小麦基因型在 80%和 50%田间持水量（FC）条件下的生物量分配、形态和生理特征。在补充田间试验中还评估了一些关键特征。
发现二倍体和四倍体基因型在干旱胁迫下会将更多的生物量分配给根系，特别是表土中的根系。我们的数据表明，这些旧基因型的 WUE 和产量较低是由于过度投资于根系，这与冠层发育严重受限有关。现代六倍体基因型被发现将较小的生物量分配给根，将较大的生物量分配给茎。这不仅确保了必要的水分吸收，而且还允许植物将更多的同化产物分配并限制水到茎。因此，六倍体基因型已经进化出稳定的冠层结构，以优化 WUE 和籽粒产量。
本研究表明，从地下到地上或更平衡的根：茎比例的生物量转移倾向于优化现代品种的用水和产量。这一发现为未来旱地小麦的选育和可持续管理策略提供了潜在的指导。© 2021 加拿大女王陛下以其权利名义出版《食品与农业科学杂志》© 2021 化学学会。经加拿大农业和农业食品部许可转载。
