| Wheat is one of the main food crops in China.The agronomic traits,quality and disease resistance of wheat are the main research directions of production and processing.The improvement of agronomic traits can improve wheat yield.With the improvement of living standards,people’s requirements for wheat quality are constantly increasing,and wheat powdery mildew has gradually become one of the main diseases affecting wheat yield and quality improvement.Under different genotypes and environmental conditions,the agronomic traits and quality of different wheat are very different,so it is very important to study the stability of wheat agronomic traits and quality.Powdery mildew is mainly affected by genotype,and early prevention of disease is the main means to control powdery mildew.Analyze the spectral rule of wheat with different resistance and predict the chlorophyll content of wheat with different resistance after powella infection by hyperspectral technology Therefore,this study explores from two aspects.On the one hand,the agronomic traits and quality stability of 27 materials in three planting areas of Yangling in Shaanxi,Nanyang in Henan and Suqian in Jiangsu were studied.On the other hand,27 wheat materials were identified for powdery mildew,establish the estimation model of SPAD value in different stages of wheat powdew infection based on partial least square method,and explore the effective method for early prediction of SPAD value of wheat powdew The main results of this experiment are as follows:(1)Agronomic traits were greatly affected by environment.The wheat yield of 27 materials in three planting regions was Yangling,Shaanxi,Suqian,Jiangsu,Nanyang,Henan.The overall order of plant height was Suqian > Nanyang > Yangling.The yield stability of different materials was Suqian > Nanyang > Yangling.The plant height stability was Yangling > Suqian > Nanyang.On the whole,the plant height and yield stability of Zhengmai 366 were best.(2)Three experimental areas had different effects on wheat grain quality.Wheat grains in Yangling,Shaanxi Province are fuller.The degree of environmental impact on the length and width of wheat grains of different materials was Yangling,Shaanxi > Nanyang,Henan >Suqian,Jiangsu.The thousand-grain weight,grain length and width stability of Fanmai 8,Xinmai 26 and M625 were excellent.The grain length and width were more stable than thousand-grain weight in the three regions.Hardness is most obviously affected by genotype and environment compared with other indexes.There was no significant difference in grain water content among the three regions,and it was relatively stable among the materials,indicating that the water content was less affected by the environment.(3)The three main indexes of protein quality were consistent on the whole.The average values of crude protein,sedimentation value and wet gluten content of all materials in three regions were Yangling > Nanyang > Suqian,the stability is Nanyang > Yangling > Suqian.M118 showed the best stability of protein quality,while Panmai 8 showed the worst stability.The stability of the three indexes was crude protein > sedimentation value > wet gluten.Wheat bulk density was less affected by environmental factors.The stability of wheat water absorption in Suqian was lower than that in the other two places.(4)The results of powdery mildew identification of 27 wheat showed that 12 materials were highly susceptible,11 materials were moderately susceptible and 4 materials were moderately resistant.The spectral changes of different resistant wheat infected with powdery mildew at 0,3,5 and 7 days were determined.At 449 nm～680 nm band,the reflectance of resistant wheat was higher than that of susceptible wheat at different infection stages,and the difference was small at 689 nm～747 nm band.There was a significant difference between wheat and healthy leaves with different disease grades in the visible region,but no significant difference in the near infrared region.The difference between infected leaves and healthy leaves was minimal at 550 nm in the visible region.(5)The SPAD value of wheat with different disease grade decreased gradually with the increase of days of infection.The characteristic bands that affected the SPAD value of wheat powdery mildew were mainly concentrated in the visible region,while the correlation between near infrared region and SPAD value was not significant.TCARI index was significantly negatively correlated with SPAD value at different infection periods.Partial least squares regression(PLSR)algorithm was used to establish SPAD models of leaves at different infection periods based on feature bands and vegetation indices.Therefore,it is proved that PLSR model based on vegetation index has better prediction effect on SPAD value of wheat powdery mildew.The SPAD accuracy of 0 and 7 days was better than that of3 and 5 days.It was considered that 0 and 7 days were the best time to predict the SPAD value of wheat powdery mildew. |
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