RESUMEN
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.
Asunto(s)
Fitomejoramiento , Triticum , Triticum/genética , Poaceae/genética , Sitios de Carácter Cuantitativo , GenotipoRESUMEN
With deep rotary tillage before sowing (DRT) as control, the effects of shallow rotary tillage with simultaneous sowing (SRT) and strip tillage under no tillage conditions along with sowing (NT) on root growth, soil moisture, and soil nitrate content of wheat (Triticum aestivum) after rice (Oryza sativa) were examined from 2016 to 2018. Compared with DRT, NT and SRT resulted in higher soil water content, and lower soil nitrate content in the plow layer before booting. There was no significant difference in root weight density and root surface area density among the treatments at jointing and anthesis stages. No significant difference was found in grain yield and aboveground plant nitrogen uptake among the treatments in the growing season of 2016-2017. In the growing season of 2017-2018, NT and SRT resulted in 10.9% and 10.5% higher grain yield and 17.5% and 12.0% higher aboveground plant nitrogen uptake than DRT, respectively. Compared with DRT and SRT, NT resulted in better work efficiency and lower seedling missing rate. In conclusion, NT could effectively improve sowing quality, enhance soil water storage ability, reduce the risk of soil nitrogen leaching, and ultimately enhance wheat yield and environmental benefits in the growing stage of wheat plantation after rice.
Asunto(s)
Oryza , Triticum , Agricultura , Nitrógeno , Suelo , AguaRESUMEN
From 2016 to 2018, a field trial on three tillage and sowing practices, deep rotary tillage before sowing (DRT), shallow rotary tillage with simultaneous sowing (SRT), and strip tillage under no tillage conditions along with sowing (NT), was conducted to evaluate shoot growth, soil nutrient uptake, and utilization of wheat (Triticum aestivum) after rice (Oryza sativa) in Guanghan, Sichuan Province, China. Compared with DRT, both SRT and NT improved tillering capacity and fertile shoot rate. In 2016-2017, grain yield did not differ among the treatments, whereas in 2017-2018, NT had significantly higher grain yield (10.9%) than DRT. Furthermore, the diffe-rence in dry matter accumulation among the treatments mainly occurred prior to wheat jointing. Total nitrogen uptake of plants was higher by 9.9% in NT than in DRT, whereas nitrogen harvest index was higher in DRT than in NT. Total phosphorus uptake was not different among the treatments. Total potassium uptake was higher in NT plants than in DRT plants. Overall, the results showed that compared with the traditional tillage practice (i.e., DRT), strip tillage practice along with sowing (i.e., NT) is an effective method for increasing grain yield and soil nutrient uptake for wheat after rice.
Asunto(s)
Oryza , Triticum , Agricultura , China , Nutrientes , SueloRESUMEN
Following a two-factor split plot design, two popular varieties ( Neimai836 and Chuanmail04) were used to study the effects of waterlogging at four growth stages (seedling, jointing, booting and anthesis) on wheat growth and yield formation during two growing seasons (2011-2012 and 2012-2013). The resulted showed that the greatest yield penalty occurred when waterlogging happened at the seedling stage (10% - 15% decrease), and it was alleviated when waterlogging happened at the other stages. Waterlogging during the seedling stage significantly reduced SPAD of 2nd-6th leaves, tillers and spike number per plant, productive ears, dry matter accumulation after flowering and dry matter at maturity. Waterlogging during the jointing stage decreased SPAD of 4th-7th leaves, and waterlogging during the booting stage reduced the SPAD of top 2nd, 3rd, 4th leaves. Waterlogging during the jointing and booting stages reduced the SPAD of flag leaf, the rate of grain filling during the gradual increase stage, the average filling rate and the 1000-grain mass. Waterlogging during the flowering stage produced limited change in yield. Therefore, waterlogging during the seedling stage was identified to have the most critical influence on wheat production under wheat/rice cropping rotations in Sichuan Province.