Study on the sugarcane ratooning ability evaluation by the morphological characteristics of sugarcane stubble

【Objective】To analyze the correlation between the morphological characteristics of the sugarcane stubble and sugarcane yield or ratooning ability，so as to provide a theoretical reference for innovation of the identification and evaluation of the sugarcane germplasm resources and germplasm of strong ratooning ability.【Method】24 traits including sugarcane biomass，above-ground agronomic traits，root system in sugarcane stubble and under-ground bud morphological characteristics in 29 sugarcane varieties（lines）were carried out. SPSS 22.0 was used for genetic variation analysis，correlation analysis，path analysis，factor analysis and system clustering.【Result】Results showed that the variation coefficients of the tested traits ranged from 7.26%- 49.47%，and the genetic diversity index ranged from 1.616 to 2.030，indicating abundant genetic variation. Except for the root-shoot ratio and number of high bud germination，the remaining 22 traits were significantly different（P<0.05，the same below）among the 29 sugarcane varieties（lines）. There was a significant or extremely significant（P<0.01）correlation between the characteristics of the stubble，biomass and ratooning ability. Path analysis showed that the stubble volume，the effective stalk number，the root crossings number，and the total number of under-ground bud were the key traits that affected the composition of the above-ground biomass of sugarcane. The effective stalk number，total number of under-ground bud and the stubble biomass had great influence on the ratoon sprouting rate. Factor analysis showed that the 22 trait indexes could be simplified to 7 factors，and the cumulative contribution rate reached 82.09%. In cluster analysis, the 29 sugarcane varieties（lines）were divided into 4 groups at genetic distances 15.00，among which LC05-136，FN09-12206，DZ07-36，GT54，GT42 and YZ08-1095 had more abundant under-ground bud banks，more developed under-ground root systems，larger biomass and stronger ratooning ability.【Conclusion】The tested sugarcane varieties（lines）show rich genetic diversity in biomass，ratooning ability and morphological characteristics of the stubble. A comprehensive evaluation model based on the morphological characteristics of sugarcane stubble, sugarcane biomass and ratooning ability has been established to evaluate the ratooning performance of sugarcane. Six sugarcane varieties（lines）with high biomass and strong ratooning ability are screened out, such as LC05-136，FN09-12206， DZ07-36，GT54，GT42 and YZ08-1095.