| The dryland wheat growing regions in Northwest China,the wheat-maize rotation regions in North China,and the rice-wheat rotation regions in South China with a sown regions of 14.378million hectares and a yield of 119.35 million tons,accounting for 61.5%and 88.9%of the country’s total wheat planting regions and output.The sulfur concentration of wheat grain is urually between 1.0-2.0 g kg?1,with most being lower than that of 1.5-1.7 g kg?1needed for the medium and strong gluten wheat.Therefore,the wheat grain sulfur concentration still needs to be improved,understanding the differences of yield,grain sulfur concentration and sulfur requirement among wheat cultivars is of great significance for wheat breeding and rational application of sulfur fertilizer for improving wheat yield with high grain sulfur concentration.In this paper,field experiments of main wheat cultivars were carried out in 47 sites in dryland wheat growing region from 2017 to 2020,wheat-maize rotation regions and rice-wheat rotation regions from 2016 to 2020.Soil and wheat plant samples collected at harvest for each experimental sites,to determine the yield,biomass,macro-amd micronutrients in grains and plants and soil nutrient concentration,with the purpose to clarify the effects of sites,cultivars,year and yield composition on yield and grain sulfur concentration,and analyze the relationship between grain grain sulfur concentration,yield and sulfur requirement.Main research results are as follows:1.The grain yield of leading wheat cultivars in dryland wheat growing regions,wheat-maize rotation regions and rice-wheat rotation regions was 4.1-6.9,6.2-9.3 and 4.4-7.1 t ha?1respectively,with an average of 5.9,8.1 and 5.9 t ha?1,the yield in wheat-maize rotation regions was significantly higher than that in dryland wheat growing regions and rice-wheat rotation regions.The contribution rate of cultivars to yield variation in dryland wheat growing regions is the highest,which is 51.1%,the contribution rate of sites to yield variation in wheat-maize rotation regions and rice-wheat rotation regions is the highest,which are 69.4%and 75.7%respectively,the contribution rate of cultivars to yield variation is 6.4%and 3.6%respectively,at the same sites,cultivars renewal is still of great significance to improve yield.Among varieties,biomass,harvest index and panicle number had greater effects on wheat yield than other factors.Wheat yield in dryland wheat growing regions was significantly positively correlated with grain number per panicle and 1000 grain weight;there was a significant negative correlation between wheat-maize rotation regions and 1000 grain weight;there was a significant negative correlation between rice-wheat rotation regions and grain number per panicle.Among different sites,the main soil factors affecting wheat yield include available potassium,available copper,the application amount of nitrogen（N）and phosphorus（P2O5）fertilizer.In wheat-maize rotation regions,the yield was significantly negatively correlated with soil available potassium;In rice-wheat rotation regions,the yield was significantly negatively correlated with available potassium,but significantly positively correlated with the amount of soil available copper,the application amount of nitrogen and phosphorus fertilizer.In the same place,breeding wheat cultivars with high biomass,harvest index and spike number,adjusting the application amount of nitrogen and phosphorus fertilizer,soil available potassium and available copper are conducive to obtain high yield.2.The grain sulfur concentration of leading wheat cultivars in dryland wheat growing regions,wheat-maize rotation regions and rice-wheat rotation regions was 1.73-2.27,1.59-2.01and 1.42-1.73 g kg?1 respectively,with an average of 1.98,1.78 and 1.53 g kg?1,the sulfur concentration of grain in dryland wheat growing regions was significantly higher than that in wheat-maize rotation regions and rice-wheat rotation regions.In wheat interval,the sulfur concentration of wheat grain is mainly affected by cultivars gluten type and yield dilution.In the same wheat regions,it is mainly affected by cultivtrs,sites and year.The contribution rate of cultivars to the variation of grain sulfur concentration was the highest in dryland wheat growing regions,which was 13.1%,the contribution rate of sites to grain sulfur concentration variation in wheat-maize rotation regions and rice-wheat rotation regions is the highest,which were 34.2%and 52.0%respectively,the contribution rate of cultivars was 25.4%and 7.1%respectively.The effects of harvest index and grain sulfur uptake on wheat grain sulfur concentration were greater than other factors.There was a significant positive correlation between 1000 grain weight and aboveground sulfur absorption in dryland wheat growing regions;there was significantly negatively correlated with yield and positively correlated with sulfur harvest index in wheat-maize rotation regions;there was no significant relationship between1000 grain weight and aboveground sulfur absorption in rice-wheat rotation regions.Grain sulfur concentration was significantly positively correlated with grain nitrogen,phosphorus,magnesium,iron,zinc and manganese concentration in three wheat production regions,but only with grain zinc,calcium and copper in individual wheat regions,and significantly positively correlated with grain zinc in dryland wheat growing regions;there was a significant positive correlation with grain calcium in wheat-maize rotation regions;there was a significant positive correlation with grain copper in rice-wheat rotation regions.The main soil factors affecting wheat grain sulfur concentration include p H,soil available iron,available manganese,available zinc and available sulfur concentration.In DW,the higher GSC of Yongshou wheat compared with that of Yangling may be due to the significant higher soil available phosphorus and sulfur concentration;in wheat-maize rotation regions,grain sulfur concentration was significantly positively correlated with soil available iron and manganese;in rice-wheat rotation regions,the sulfur concentration of wheat grain was significantly negatively correlated with soil p H,available zinc and available sulfur,and positively correlated with available iron.At the same site,breeding wheat varieties with low harvest index and high grain sulfur absorption,regulating soil p H,available iron,available manganese,available zinc and available sulfur concentration,and improving soil sulfur supply capacity is conducive to improving wheat grain sulfur concentration.3.In dryland wheat growing regions,wheat-maize rotation regions and rice-wheat rotation regions,the grain sulfur concentration of leading wheat cultivars under the same yield level is significantly different.The sulfur requirement of wheat cultivars in each wheat regions is 3.7-6.4,3.2-5.1 and 2.5-4.2 kg Mg?1 respectively,with an average of 4.9,3.9 and 3.2 kg Mg?1.In order to reasonably apply sulfur fertilizer,the prediction model of sulfur requirement of wheat cultivars was constructed based on the yield and grain sulfur concentration of each wheat regions.The standard root mean square error（n RMSE）of the model was less than 10%and the regression significance was higher than 5%.It can accurately predict the sulfur requirement of wheat cultivars with different yield and sulfur concentration levels.The average fitting sulfur requirement of dryland wheat growing regions,wheat-maize rotation regions and rice-wheat rotation regions were 4.5,3.7 and 3.7 kg Mg?1 respectively.When the yield increased from low to high,the sulfur requirement of wheat cultivars in dryland wheat growing regions and rice-wheat rotation regions decreased by 16.3%and 23.4%respectively,while that in wheat-maize rotation regions increased by 7.6%.When the grain sulfur concentration increased from 1.5 g kg?1 to 1.8 g kg?1,the sulfur requirement of wheat cultivars in dryland wheat growing regions increased by 17.2%,when the grain sulfur concentration increased from 1.2 g kg?1 to 1.8 g kg?1,the sulfur requirement of wheat cultivars in wheat-maize rotation regions and rice-wheat rotation regions increased by 21.4%and 116.5%.When applying sulfur fertilizer in wheat production,the sulfur requirement should be determined according to the yield and grain sulfur concentration of wheat cultivars planted in different wheat regions,and then combined with the sulfur supply capacity of soil to determine the reasonable amount of sulfur fertilizer.To sum up,in wheat production,we should comprehensively consider the variety factors affecting yield and grain sulfur concentration in different wheat regions,improve soil p H and soil fertility,determine the sulfur requirement according to the yield potential and target grain sulfur concentration of cultivars,and reasonably apply sulfur fertilizer in combination with soil available sulfur concentration and sulfur supply capacity,so as to achieve high yield,quality,efficiency and green production of wheat. |
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