Plant Breeding, TUM School of Life Sciences, Technical University of Munich, Liesel-Beckmann-Straße 2, 85354, Freising, Germany.
Theor Appl Genet. 2021 Jun;134(6):1663-1675. doi: 10.1007/s00122-020-03761-3. Epub 2021 Feb 11.
Carbon isotope discrimination is a promising trait for indirect screening for improved water use efficiency of C crops. In the context of a changing climate, drought is one of the major factors limiting plant growth and yield. Hence, breeding efforts are directed toward improving water use efficiency (WUE) as a key factor in climate resilience and sustainability of crop production. As WUE is a complex trait and its evaluation is rather resource consuming, proxy traits, which are easier to screen and reliably reflect variation in WUE, are needed. In C crops, a trait established to be indicative for WUE is the carbon isotopic composition (δC) of plant material, which reflects the preferential assimilation of the lighter carbon isotope C over C during photosynthesis. In C crops, carbon fixation is more complex and δC thus depends on many more factors than in C crops. Recent physiological and genetic studies indicate a correlation between δC and WUE also in C crops, as well as a colocalization of quantitative trait loci for the two traits. Moreover, significant intraspecific variation as well as a medium to high heritability of δC has been shown in some of the main C crops, such as maize, sorghum and sugarcane, indicating its potential for indirect selection and breeding. Further research on physiological, genetic and environmental components influencing δC is needed to support its application in improving WUE and making C crops resilient to climate change.
碳同位素分馏是一种很有前途的性状，可以间接筛选出 C 作物水分利用效率提高的品种。在气候变化的背景下，干旱是限制植物生长和产量的主要因素之一。因此，培育工作的重点是提高水分利用效率（WUE），这是作物生产应对气候变化和可持续性的关键因素。由于 WUE 是一个复杂的性状，其评估相当耗费资源，因此需要寻找更容易筛选且能可靠反映 WUE 变化的替代性状。在 C 作物中，一种被认为与 WUE 相关的性状是植物材料的碳同位素组成（δC），它反映了光合作用中 C 对 C 的优先同化。在 C 作物中，碳固定过程更为复杂，因此 δC 取决于比 C 作物更多的因素。最近的生理和遗传研究表明，δC 与 C 作物的 WUE 之间存在相关性，以及这两个性状的数量性状位点也存在共定位。此外，在一些主要的 C 作物（如玉米、高粱和甘蔗）中，δC 具有较大的种内变异和中到高的遗传力，表明其在间接选择和培育方面具有潜力。需要进一步研究影响 δC 的生理、遗传和环境因素，以支持其在提高 WUE 和使 C 作物适应气候变化方面的应用。
