Research On Yield And Nitrogen Efficiency Of New Wheat Varieties With Different Fertility Levels

Fertilization and variety have significant effects on wheat yield.Screening and breeding nutrient-efficient wheat varieties have important implications for sustainable agricultural development in China.We conducted a two-year field experiment on two soil fertility in loess soil in the Guanzhong Plain of Shaanxi Province.Based on a two-factor randomized block design of fertilization and variety,the yield and nitrogen efficiency of wheat varieties Zhongmai 578,Weilong 169 and Xiaoyan 22 were investigated.The fertilization treatments included no fertilization（CK）,farmer fertilization（FP）,and Optimized fertilization（BMP）.The tested wheat varieties were Zhongmai 578,Weilong 169,and Xiaoyan 22.The obtained main results and conclusions are as follows:（1）Fertilization and variety significantly affect wheat yield.Wheat yield ranged from3151-8110 kg ha^-1.Wheat spike number ranged from 385-552 10⁴ spike ha^-1,kernel number ranged from 24-38 per spike,and thousand-grain weight ranged from 41-53 g.There was no significant difference in yield between BMP and FP treatments,both of which were significantly higher than CK.The wheat varieties with higher yields on both soil fertility were Weilong 169 and Xiaoyan 22.（2）Fertilization and variety significantly affect nitrogen efficiency in wheat.Nitrogen use efficiency ranged from 46-64 kg kg^-1,nitrogen harvest index ranged from 80%-87%,and the nitrogen requirement for 100 kg of grain ranged from 1.90-2.24 kg.The nitrogen use efficiency and nitrogen harvest index in BMP treatment were significantly higher than those in FP treatment,while the nitrogen requirement for producing 100 kg of grain was the opposite.Weilong 169 had higher nitrogen use efficiency and nitrogen harvest index than Zhongmai578 and Xiaoyan 22,and its nitrogen requirement for 100 kg of grain was lower.（3）Fertilization and variety significantly affect the tillering ability and spike rate of wheat.The tillering ability of wheat varieties ranged from 2.2-3.4,and the spike rate ranged from0.36-0.57.Fertilization significantly enhanced the tillering ability of wheat.The tillering ability of Weilong 169 and Xiaoyan 22 was significantly higher than that of Zhongmai 578.Organic-inorganic compound fertilization reduced the ineffective tillers of wheat and increased the spike rate.The spike rate of Zhongmai 578 and Xiaoyan 22 was significantly higher than that of Weilong 169.（4）The roots of different wheat varieties showed some differences.The root length density of wheat varieties in the 0-20 cm soil layer ranged from 6.57-23.21 km m^-3,the root surface area density ranged from 11.27-25.57 m² m^-3,the root volume density ranged from1.33-2.47 dm³ m^-3,and the root weight density ranged from 0.43-0.80 kg m^-3.Among different wheat varieties,the root length density and root surface area density of Xiaoyan 22 and Weilong 169 were slightly higher than those of Zhongmai 578,while their root weight density was similar.（5）Fertilization and variety significantly affect the SPAD values of wheat flag leaves at flowering and the rate of change in SPAD values after flowering.The SPAD values at wheat flowering range from 39-59,and the rate of change in SPAD values of flag leaves after flowering ranges from 0.0439-0.1141.Fertilization significantly increases the SPAD values of wheat flag leaves at flowering,and compared to Weilong 169 and Xiaoyan 22,Zhongmai 578had a slower rate of SPAD decline after anthems.（6）Fertilization and variety significantly affect wheat water-soluble carbohydr-ates content at pre-anthesis,water-soluble carbohydrates content at maturity,water-soluble carbohydrates transport amount,water-soluble carbohydrates transport rate,and the contribution rate of water-soluble carbohydrates to yield.The water-soluble carbohydrates content at pre-anthesis of wheat ranged from 997-2205 kg ha^-1,water-soluble carbohydrates content at maturity ranged from 94-371 kg ha^-1,water-soluble carbohydrates transport amount ranged from 1442-2057 kg ha^-1,water-soluble carbohydrates transport rate ranged from 68%-94%,and the contribution rate of water-soluble carbohydrates to yield ranged from 14%-36%.There were differences in the transport capacity of water-soluble carbohydrates to the grains among different wheat varieties,and Weilong 169 had a stronger water-soluble carbohydrates transport capacity.In summary,the experimental results show that the nitrogen efficiency of the BMP treatment is higher than that of the FP treatment,and there is no significant difference in yield between the two treatments.The newly developed variety,Weilong 169,has high nitrogen utilization efficiency and yield.Therefore,the BMP is recommended with wheat variety of Weilong 169 in the Guanzhong area of Shaanxi to obtain high yield and nitrogen efficiency.