Accurate Evaluation And Mechanism Anaiysis Of Mechanical Strength Of Sugarcane Stalk

Lodging is an important factor limiting sugarcane yield,and it is closely related to the mechanical strength of the stalk.In view of the fact that the lodging is one of the key problems limiting sugarcane production in China,this study carried out the research on the accurate evaluation of the mechanical strength of sugarcane stalks and the mechanism analysis,in order to provide reference for the cultivation of sugarcane lodging resistant varieties.In this study,117 natural sugarcane strains in 2019 were used as test materials to determine the mechanical properties of the materials.It was found that the puncture force of mature sugarcane internodes was significantly positively correlated with the breaking force of immature internodes(p<0.001),and the mechanical parameters were also significantly positively correlated between different test blots(p<0.001).The research results achieved the accurate evaluation of the mechanical strength of sugarcane stalks.On the basis,a total of 721 sugarcane germplasms were collected in 2019 and 2020,and calibrated in combination with the near infrared spectroscopy(NIRS)modeling strategy,calibration,internal cross validation and external validation,equations with high relative analysis error(RPD)and calibration coefficient(R~2)were generated,especially the puncture force equation with RPD of 17.7 and R~2of 1.0.All the predicted and real values of the equation show excellent linear correlation and good prediction performance.The established puncture force equation was verified by using the puncture force of 300 stalks collected in 2021.The results showed that the measured values were significantly correlated with the predicted values of the equation.In general,the established equations of puncture force and breaking force provide a feasible scheme for the high flux analysis of sugarcane stalk mechanical strength.Secondly,the established method was applied to the evaluation of sugarcane germplasm population.It was found that the variation range of the mechanical strength of the stalks of the population materials was large,and the correlation of the mechanical strength of the stalks of the materials of the same strain among different experimental blots was significant.The materials with extreme differences in the mechanical strength of the stalks were further screened out.Combined with lodging resistance index,the lodging resistance of sugarcane stalks was evaluated.It was found that there was a certain internal relationship between the mechanical strength of sugarcane stalks and lodging resistance.Finally,the materials with extreme difference in mechanical strength of stalks and different lodging resistance(GT42 and LC05-136)were analyzed.The results showed that the difference in mechanical strength of stalks was related to stalk bark tissue,but not to stalk pith.The mechanical strength of stalk bark tissue of different varieties affected the lodging resistance of sugarcane stalks;Cytological analysis showed that the strains with high mechanical strength of sugarcane stalks had relatively high contents of cellulose,hemicellulose and lignin,and cellulose was significantly correlated with the mechanical strength of sugarcane stalks(the correlation coefficient was more than 0.9).Further study found that the material with extremely high mechanical strength of sugarcane stalk also had high crystallinity and polymerization degree of cellulose,and the crystallinity and polymerization degree were significantly correlated with the mechanical strength of sugarcane stalk.The study preliminarily revealed the internal mechanism of the mechanical strength of sugarcane stalk.To sum up,this study is the first to carry out accurate evaluation of sugarcane stalk mechanical strength and establish corresponding high-throughput analysis methods,and apply them to the evaluation of sugarcane germplasm population materials.Through the fine mechanical analysis and cytological analysis of sugarcane stalks,the internal influence mechanism of sugarcane stalk mechanical strength was preliminarily analyzed,and the research provided theoretical and technical support for the cultivation of sugarcane lodging resistant varieties.