| In this study,600 corn inbred straws collected from the United States and China were used.Based on fiber filter bag technology and near-infrared diffuse reflectance spectroscopy,six corn stalk quality traits were obtained.At the same time,the lodging traits were investigated in the field,and the stalk stem,puncture resistance,bending resistance and other traits were measured and cytological evaluated.The following results were obtained:The content of acid detergent fiber and neutral detergent fiber in straws measured by cellulose analyzer based on filter bag technology is not significantly different from that predicted by near-infrared mathematical model using near-infrared spectrometer.Therefore,the near-infrared mathematical model was used to predict for six straw quality traits analysis.The coefficients of variation among the six traits such as ADF(Acid detergent fiber),NDF(Neutral detergent fiber),CEL(Cellulose),ADL(Acid detergent lignin),HCEL(Hemicellulose)and IVDMD(In vitro dry matter digestibility)in the straw components of the test samples were varied greatly.Among them,the largest range of IVDMD is from 12.04% to 58.77%,and the range of ADL variation is from 1.06% to 6.93%.The maximum difference between the two extreme values of ADL is 6.5 times,and the difference between the two extreme values of HCEL is 1.5 times.The coefficient of variation results showed that IVDMD and ADL were the largest,CV were 22.48% and 22.06%,respectively,and NDF and HCEL were less variable,and CV were 8.26% and 7.32%,respectively.The results indicated that there were extensive genetic differences among the six quality traits in the straw composition.Correlation analysis of quality traits showed that the six quality traits of the tested inbred lines were more significantly or significantly correlated.Among them,ADF has the highest correlation with NDF,which r = 0.924.There was a significant or extremely significant negative correlation between IVDMD and the other five quality traits,and the correlation coefficient was large,indicating that the chemical composition of straw cell wall has a decisive role in the IVDMD index.Using IVDMD as the dependent variable,ADF,NDF,CEL,ADL and HCEL as independent variables,multivariate-stepwise regression analysis showed that the chemical compositions of straw cell wall had a significant effect on IVDMD,which could explain the 88.6% phenotypic variation of IVDMD.The results of stem diameter(SD,Stem Diameter),strength of resistance to bending(S,Strength of resistance to bending)and puncture strength(RPR,Rind penetrometer resistance),which related to lodging,showed that there were extensive genetic variations The average values of SD,RPR and S were 18.87%,39.20% and 54.04%,respectively.The maximum amplitude of S is 15.10~93.80%,and the minimum amplitude of SD is 5.77~28.40%.The coefficient of variation results show that the minimum CV of stem is 15.58%,and the maximum CV resistance is 29.36%,indicating the degree of variation of these three traits.Correlation analysis showed that the correlation between RPR and ADF,HCEL was not significant,whereas there was significant or extremely significant correlation with other 7 traits.The stem diameter and lignin contribute significantly to the puncture strength,which can totally explain the phenotypic variation of RPR 23.9%.Using the optical microscope and scanning electron microscope were used to observe the tissue structure of the test sample.It was found that cellulose and lignin can affect the puncture strength of the plant by affecting the morphological structure of the mechanical tissue.The higher the contents of cellulose and lignin were,the stronger the puncture ability of inbred line straws.And a few elite inbred lines corresponding to smaller and larger traits were screened,as parent material,for excavation and creation of high-cellulose(energy type),high-lignin(lodging resistance type)and high digestibility(silage type)germplasm resources and breeding of new varieties provide material and theoretical basis. |
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