Abstract
To understand the co-evolution in yield-related traits with the breeding, selection, and introduction of genotypes for increased grain yield, field experiments were carried out at two sites in the western area of the Loess Plateau in China that differed in hydrothermal conditions. Sixteen genotypes of spring wheat introduced and grown over the past 120 years were compared in terms of their yield and yield-related traits. As the grain yield increased, the spike number per unit area and the grain number per spike increased linearly, but the 1000-kernel weight was not correlated with grain yield. In the more recent genotypes, anthesis was initiated significantly earlier, although the length of the period from anthesis to maturity remained unchanged. Water use and the Effective Use of Water (EUW) for aboveground biomass before anthesis and the contribution of pre-anthesis aboveground biomass to grain yield all decreased as grain yield increased. Soil water content at anthesis was negatively correlated with aboveground biomass at anthesis, but positively correlated with grain yield. Conclusively, breeding in spring wheat over the past century has increased the yield of new genotypes by (1) increasing the number of grains per unit area; (2) shortening the period of vegetative growth; (3) decreasing EUW and the soil water use before anthesis; thereby (4) retaining more soil water and increasing biomass accumulation after anthesis. Future spring wheat breeding for this dryland region should determine whether the time for grain filling from anthesis to maturity can be extended to enable greater use of environmental resources and higher yields.
Highlights
Wheat (Triticum aestivum L.), one of the major food crops worldwide, is grown on nearly 70% of the cultivated land in developed countries and about 50% in developing countries
Pearson’s correlation coefficient and linear regression were used for ascertaining the correlation, if any, among the best linear unbiased prediction (BLUP) of phenology, water use, soil water content at anthesis, aboveground biomass, harvest index, Water use efficiency (WUE), and grain yield
Two-way analyses of variance showed that grain yield and yield-related traits, including yield components, pre-anthesis aboveground biomass accumulation, postanthesis aboveground biomass accumulation, and harvest index showed a significant G × E interaction (p < 0.05), but not aboveground biomass at maturity, water use and WUE (Table 1)
Summary
Wheat (Triticum aestivum L.), one of the major food crops worldwide, is grown on nearly 70% of the cultivated land in developed countries and about 50% in developing countries. The history of wheat breeding in the cold environment of western Siberia over the past 100 years showed that genetic gain in yield potential was achieved neither by reducing plant height nor by incorporating Rht genes, but 40% was associated with greater 1000-kernel weight, 20% to more grains per unit area, and by greater resistance to leaf rust [8]. We sought to identify (1) the key factors affecting the increase in grain yield in the different genotypes developed over the 120 years; and (2) the key directions for breeding future lines of spring wheat suited to dryland farming in North-West China
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