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Synthetic hexaploid wheat (SHW) is a useful genetic resource that can be used to improve the performance of common wheat by transferring favorable genes from a wide range of tetraploid or diploid donors. From the perspectives of physiology, cultivation, and molecular genetics, the use of SHW has the potential to increase wheat yield. Moreover, genomic variation and recombination were enhanced in newly formed SHW, which could generate more genovariation or new gene combinations compared to ancestral genomes. Accordingly, we presented a breeding strategy for the application of SHW—the 'large population with limited backcrossing method'—and we pyramided stripe rust resistance and big-spike-related QTLs/genes from SHW into new high-yield cultivars, which represents an important genetic basis of big-spike wheat in southwestern China. For further breeding applications of SHW-derived cultivars, we used the 'recombinant inbred line-based breeding method' that combines both phenotypic and genotypic evaluations to pyramid multi-spike and pre-harvest sprouting resistance QTLs/genes from other germplasms to SHW-derived cultivars; consequently, we created record-breaking high-yield wheat in southwestern China. To meet upcoming environmental challenges and continuous global demand for wheat production, SHW with broad genetic resources from wild donor species will play a major role in wheat breeding. [ABSTRACT FROM AUTHOR]

Seedling establishment is critical for grain yield and net benefits of wheat in wet clay soil after puddled rice harvest in the Yangtze River basin (YRB) of China. A wet-resistant rotary strip-till seeder (WR seeder) was developed to drill seeds in zero tillage (ZT) conditions with complete rice residue mulching. The rotary blades adopted were medium radius C type blades creating a 50–60 mm wide and 30–50 mm deep furrow for seed placement. The pressing roller, usually used in the traditional wheat seeders, has been replaced by two ground wheels covered in rubber to reduce the mud adhesion. Moreover, a stainless-steel chain was installed behind the machine for better seed covering with soil. Based on three-year long field comparisons with the traditional deep tillage seeder (DT seeder) and a rototiller disc-type seeder with shallow tillage (SHT seeder), the six-row WR seeder significantly enhanced seedling establishment, and reduced energy consumption by 51.3% and 24.5%, respectively. The WR seeder also conserved the topsoil moisture. Over three years, the WR seeder produced similar grain yield to the SHT seeder, but 3.1% more than the DT seeder. Moreover, the net profit with WR seeder increased by 39.4% and 0.9% compared to the DT and SHT seeders, respectively. Furthermore, comparisons across the YRB also confirmed the positive effects of the WR seeder on grain yield and economic benefits over the conventional seeding practices. Thus, it was demonstrated that the improved seeder is an optimal option to enhance the RW system productivity in the YRB. • A strip-till seeder was developed for wheat sowing in wet clay fields. • Yield superiority and energy efficiency with the improved seeder were demonstrated. • The wheat yield increase resulted from the large increase in fertile spikes. • Effective residue management enhances the seeder performance. [ABSTRACT FROM AUTHOR]

Knowledge about the key traits related to genetic gains in grain yield (GY) is necessary for understanding the main yield‐limiting factors and guiding future wheat (Triticum aestivum L.) breeding. The objective of this research was to investigate the genetic progress in GY and the associated physiological traits in popular wheat cultivars released from 1969 to 2012 in southwestern China. Field experiments included eight representative cultivars that were evaluated at three experimental sites for three growing seasons. Grain yield increased at a linear rate of 0.69% or 52.52 kg ha−1 yr−1, which was mainly attributed to the increases in dry matter (DM) accumulation at maturity, harvest index (HI), and thousand‐kernel weight (TKW). The soil and plant analyzer development (SPAD) values of flag and penultimate leaves at anthesis increased with the year of release and were significantly related to GY. Significant genetic gains were made in both nonstructural carbohydrate (NSC) translocation and NSC translocation efficiency from anthesis to maturity, and there was a trend over time towards a high net photosynthetic rate (Pn) of flag leaf and canopy apparent photosynthesis (CAP) at anthesis and at 30 d post‐anthesis (DPA). In addition, the linear increases in N uptake efficiency and N utilization efficiency were both significant and positive related to GY. Therefore, these key physiological traits can be used as selection criteria for further improving yield potential. Our results also reveal the potential for using synthetic hexaploid wheat in high‐yielding wheat breeding. [ABSTRACT FROM AUTHOR]

Field trials were carried out during 2011-2013 in three locations on 10 wheat genotypes. Traits that were investigated included grain weight, grain-filling duration, grain-filling rates and the lag phase from flowering to the commencement of effective grain filling. The grain-filling duration and rate were fitted by Richard’s equation in thermal time (growing degree-days (GDD), base temperature 9ºC). A combined ANOVA across environments showed that the grain weight was mainly affected by genotype, while most of the other grain-filling characters were influenced by the environment and G × E interactions. Grain filling lasted between 362 to 400 GDD and included a lag phase that ranged from 67 to 86 GDD. Both the effective and maximum rates of grain filling ranged from 0.12 to 0.15 mg GDD−1 and 0.18-0.22 to GDD−1, respectively. The lag phase was positively correlated with grain weight and rates of grain filling, whereas days to anthesis were significantly negatively correlated with the lag phase and both rates of grain filling. Temperature during grain filling was negatively correlated with the lag phase. The variation in grain weight was positively associated with the rate of grain filling, which, in turn, was related to the grain number per unit area. A compensating variability existed among the genotypes in both the grain number and grain-filling rate. The study of genotypic stability demonstrated that Chuanmai42 and Chuanmai104 had high grain weight and stability among most of the grain-filling parameters, and also had high grain yield. Chuanmai42 and Chuanmai104 were the best genotypes for improving the yield potential and grain weight stability. [ABSTRACT FROM AUTHOR]

The effects of climate warming on wheat yields vary geographically under different warming scenarios. Such variations reflect real climatic differences and our insufficient understanding of how physiological processes respond to warming conditions. In this study, a 16-year trial comprising three crop production systems (CPSs) and a 5-year trial including seven cultivars were conducted in the Sichuan Basin of China to investigate the effects of climate warming on the phenological development, grain yield (GY), dry matter (DM) accumulation and translocation of wheat. The three CPSs included conventional rotary tillage with residue removal for both rice and wheat (CPS1), conventional rotary tillage with the wheat residue incorporated for the rice following zero tillage with residue-mulching for wheat (CPS2), and zero tillage and residue-mulching employed for both wheat and rice (CPS3). The wheat cultivars used in this study were all spring-type wheat, and the trials were planted from 26 to 30 October each year, irrigation was applied only at the seeding and topdressing stages and in amounts less than 20 mm. The results showed that mean of daily mean temperature from November to March (MT Nov-Mar) and November to April (MT Nov-Apr) significantly increased by 0.0964 °C yr-1 and 0.0947 °C yr-1 from 2004 to 2020, respectively. This warming caused earlier flowering and significantly decreased mean temperature from anthesis to maturity (P ost AT mean) by 0.091 °C yr-1. However, grain number m-2 was unaffected by this warming. Cooler and longer grain-gilling periods (GFP) lead to larger grain sinks and allow more preanthesis assimilates to be transported to the grain, resulting in increased individual grain weight and harvest index under all CPSs and all cultivars. There were no significant differences in sensitivities of GY and DM related trait responses to temperature change between CPSs or between cultivars. Averaged over all CPSs, GY increased 741.9 kg ha-1 with each 1 °C increases in MT Nov-Apr. The increase in yield was mainly attributable to increase in grain weights while grain number m-2 was maintained. In addition, the MT Nov-Apr values in the Sichuan Basin were predicted to reach 14.7 °C and 16.5 °C by the end of this century under the SSP245 and SSP585 climate change scenarios, respectively. When the CO 2 concentration was fixed at 350 ppm, the Agricultural Production Systems SIMulator (APSIM) model showed that the increasing MT Nov-Apr values significantly increased the GY under the SSP245 scenario, but the GY was initially positively and then negatively affected under the SSP585 scenario. These results lay the foundation for developing adaptation strategies to address future climate change in climates like that of Sichuan Basin and ensure wheat supplies. • An increasing MT Nov-Apr strongly advanced the anthesis date and increased the GY by 742 kg ha-1 °C-1 in the Sichuan Basin. • High GY obtained from high MT Nov-Apr because of earlier flowering and cooler GFP induced larger grain sinks, DMt and CPAG. • Under SSP245 scenario from 2021 to 2100, increasing MT Nov-Apr values are expected to increase the wheat yield using APSIM. • No significant differences in slopes of GY response to temperature change was detected between CPSs or between cultivars. [ABSTRACT FROM AUTHOR]

Optimizing tillage and seeding strategies is important for increasing crop productivity and nitrogen use efficiency (NUE) while reducing environmental impact. A newly developed innovative no-till seeding (INtS) technology was shown to effectively enhance seeding quality and increase wheat yield in wet clay soil after puddled rice harvest in the Yangtze River Basin (YRB) of China. However, comprehensive assessments of the yield, NUE, and eco-environmental benefits of INtS technology have not been performed. The present study conducted a consecutive three-year field experiment combining field plots and microplots with the 15N tracer method using two wheat seeding technologies (INtS and typical rotary-till seeding (TRtS) technology) and three nitrogen (N) application rates (0, 90, and 180 kg ha−1). The study evaluated the yield, NUE, fate of fertilizer/straw N, N budgets, and environmental footprints of wheat production after rice harvesting. The results showed that compared with TRtS, the average yield, N uptake and NUE of wheat under INtS technology increased by 27.2%, 28.9%, and 31.9%, respectively. By tracing the multi-seasonal fate of 15N-labeled fertilizer/straw N in soil-crop systems, it was found that 43.8% and 6.0% of fertilizer N and rice straw N applied in the first wheat growing season were recovered by wheat plants in the same season under INtS technology, which significantly decreased to 29.0% and 4.1% for TRtS technology. Over the five growing seasons, the cumulative recoveries of fertilizer and straw N for INtS technology were 26.2% and 15.6% higher, while the total fertilizer and straw N losses were 20.6% and 20.0% lower than those for TRtS technology, respectively. Over 50% of straw N remained in the soil after the fifth growing season, while only 14.5–23.6% of fertilizer N remained. In addition, INtS technology significantly reduced the fertilizer/straw N losses when applied in the subsequent rice growing season. Unlike TRtS technology, INtS could maintain a low-level soil N balance (2.1 kg N ha−1 for N180) and generate less soil surface N surplus in the wheat growing season. On average, INtS significantly reduced the carbon footprint and N footprint in the wheat growing season by 26.8% and 19.1%, respectively. In conclusion, INtS technology can significantly improve crop production and agricultural sustainability while minimizing negative environmental impacts for wheat production after rice cultivation in the YRB of China and other areas of the world with similar field conditions. [Display omitted] • Innovative no-till seeding (INtS) technology increased grain yield by 27.2% and N uptake by 28.9%. • INtS technology showed higher fertilizer/straw N use efficiency and lower fertilizer/straw N losses. • INtS technology could maintain a low-level soil N balance and soil surface N surplus. • INtS technology reduced the carbon footprint and N footprint by 26.8% and 19.1%, respectively. • Higher productivity and N use efficiency while reducing environmental pressure can be achieved by INtS technology. [ABSTRACT FROM AUTHOR]