| Leymus chinensis is one of the important building species in the eastern steppe region of Eurasia.It is also an excellent feed resource and plays an important role in ecological security and animal husbandry production in China.However,the agronomic traits and feeding value of large-scale wild Leymus chinensis germplasm resources have not been clarified.Besides,the distribution pattern of resources on a large regional spatial scale is still unclear.For this purpose,a comprehensive evaluation of the agronomic traits and quality of Leymus chinensis germplasm resources was made,the agronomic traits and quality differences of Leymus chinensis germplasm resources under different regions and grassland types were studied,the best evaluation methods and Leymus chinensis germplasm resources were screened.Also the near-infrared spectroscopy(NIRS)technology was used to take a rapid evaluation of Leymus chinensis quality.Through this research it could provid theoretical basis and technical support for the Leymus chinensis varieties selection and scientific utilization.This study collected 102 wild Leymus chinensis germplasm resources from China and Mongolia.The agronomic traits and quality of Leymus chinensis germplasm resources were researched with the same quality garden resources as a platform.Then the agronomic characters and quality related indicators of Leymus chinensis germplasm resources were studied via variance analysis,correlation anallysis,principal component analysis,membership function,cluster analysis,correspondence analysis,partial least squares and NIRS technology.The agronomic traits and quality of Leymus chinensis germplasm resources were explored under the large regional scale.The resource distribution pattern and influencing factors were found out.The NIRS quantitative analysis models for the quality evaluation and screening of Leymus chinensis germplasm resources was established.And internal cross-examination and external verification were carried out on the established models.The conclusions are as follows:(1)The 102 wild Leymus chinensis germplasm resources with different sources had a large degree of variation in agronomic characters and quality,and had rich genetic diversity.The plant height had the highest variation among the agronomic traits which is 236.43%.The CF had the highest variation among the quality indicators which is 54.17%.And the plant height of Leymus chinensis germplasm resources was significantly positively correlated with its fiber content.In clustering analysis,resources from the same or similar geographical environment could be clustered into one category,indicating that resources from the same geographical environment had close relationship.(2)The best method for the agronomic traits evaluation of Leymus chinensis germplasm resources was principal component analysis.RFV was more suitable for the quality evaluation of Leymus chinensis germplasm resources.The membership function method was suitable for the comprehensive evaluation of agronomic traits and quality of Leymus chinensis.According to the resources evaluation by the best methods,the best quality Leymus chinensis germplasm resource was LC99 from Central Province of Mongolia;LC7 which was from meadow grassland in Songliao Plain performed the best,not only in agronomic traits but also in the comprehensive evaluation of quality and agronomic traits.(3)The agronomic traits and quality of Leymus chinensis germplasm resources were obviously different in different regions and have different characteristics.The plant height of resource in Songliao Plain was the highest,with an average of 64.81cm,while the yield of resource in North China Plain was the highest,with an average of 0.99kg/m2.The quality of Leymus chinensis germplasm resources was better in North China Plain and Eastern Inner Mongolia,while the the quality was lower in Central Inner Mongolia and Loess Plateau because of the higher fiber content and the lower CP content.In general,the order of comprehensive characters of Leymus chinensis germplasm resources in the natural geographical regions was as follows,North China Plain>Songliao Plain>Eastern Inner Mongolia>Xiao Xing’anling-changbai Mountain>Central Inner Mongolia>Loess plateau.From the perspective of different areas in Mongolian Plateau,the yield of Inner Mongolia Leymus chinensis germplasm resources was 34.75%higher than that of Mongolia,and the plant cluster was significantly larger than that of Mongolian Leymus chinensis.From the perspective of different grassland types,the Leymus chinensis germplasm resources of meadow grassland had the best quality,while the resource of temperate desert grassland had the worst quality because of the high fiber content and low CP content.(4)On the large regional scale,large climatic conditions dominated the change trend of Leymus chinensis germplasm resources traits.At the same time,heterogeneous small habitat under the large environment could promote small-scale variation of Leymus chinensis traits.The distribution pattern of agronomic traits of Leymus chinensis germplasm resources was affected by the combination of latitude and altitude,but altitude was the more important factor.The quality distribution pattern of Leymus chinensis germplasm resources had a certain correlation with the natural geographical areas,but it was greatly affected by the small habitat.In the same altitude region of the Mongolian Plateau,latitude was also the main factor affecting the distribution pattern of Leymus chinensis germplasm resources.(5)The 9 NIRS detection and evaluation models of Leymus chinensis germplasm resources quality was established and verified.The models of CP,NDF,ADF and Ash could achieve accurate quantitative detection.Because the R2 of them were all above 90%while the RPD were all above 3.The models of DM,CF,ADL and GE could perform general quantitative detection.Because the R2 of them were all above 80%while the RPD were all above 2.5.The EE model could not be used for quantitative detection and needed further study and improvement.Because the R2 of model was 46.11%and RPD was 1.36. |
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