Drought resistance index screening and drought resistance evaluation of commonly-used sugarcane parents in field

【Objective】To screen drought resistance indicators for sugarcane in the field and evaluate drought resistance of commonly-used sugarcane parents，in order to provide theoretical basis for subsequent drought resistance identification of sugarcane germplasm resources and formulation of drought resistance evaluation standards，as well as to provide germplasm guarantee for breeding new drought-resistant sugarcane varieties and study on sugarcane drought resistance mechanism.【Method】Twenty commonly-used sugarcane parents，of which 3 were foreign and 17 domestic ones，were used as materials，two treatments of normal irrigation control and drought stress were set up to investigate agronomic trait indexes related to drought resistance. The indexes related to sugarcane drought resistance were selected by significance analysis and correlation analysis，and drought resistance of commonly-used sugarcane parents was comprehensively evaluated by drought resistance coefficient，subordinate function value，comprehensive evaluation value（D value）of drought resistance，and cluster analysis results.【Result】Among the 48 single agronomic traits indexes，8 indexes suitable for evaluating the drought resistance of sugarcane were selected，namely moderate drought period green leaf rate，severe drought period green leaf rate，severe drought period plant height，rewatering period plant height，length of the 4th node，diameter of the 4th node，weight of the 4th node and cane yield；the drought resistance of 20 commonly-used sugarcane parents was evaluated through drought resistance coefficient，subordinate function value and D value，and drought resistance was in the order of Guitang 31（GT31）>Guitang 32（GT32）>Xintaitang 22（ROC22）>Yunzhe 89-159（YZ89-159）>Ke5>Yuetang 00- 236（YT00-236）>Taitang 172（F172）>CP72-1210>Yuetang 94-128（YT94-128）>Liucheng 03-182（LC03-182）>Funong 39（FN39）>CP80-1827>Yuetang 93-159（YT93-159）>Guitang 11（GT11）>Xintaitang 10（ROC10）>Guitang 29（GT29）> Xintaitang 16（ROC16）>Ganzhe 18（GZ18）>Xintaitang 1（ROC1）>Guitang 21（GT21）. Combining clustering analysis and field drought deficiency traits，the drought resistance was divided into 5 categories，among which CP72-1210，YT00- 236，Ke5，ROC22，YZ89-159，GT31 and GT32 were highly drought-resistant，while F172，GT11，ROC1 and ROC10 were drought-resistant，LC03-182，FN39，CP80-1827，GT29 and ROC16 were mediumly drought-resistant，and YT93-159 was not drought-resistant，and GZ18 and GT21 were extremely non-drought-resistant.【Conclusion】Eight indicators suitable for evaluating sugarcane drought resistance are screened and can be used for drought resistance identification of sugarcane germplasm resources and development of sugarcane drought resistance evaluation standards. Seven high drought-resistant varieties can be utilized as important parents for sugarcane drought resistance breeding.