Analysis Of Drought Tolerance Of BC₁F₁ Progenies Derived From Sugarcane And Erianthus Fulvus

Sugarcane（Saccharum spp.）is a major sugar crop in China,and drought affects the proper absorption of water during the growth of sugarcane,which affects its normal development and sugar accumulation,resulting in a reduction of sugarcane yield and quality.Erianthus fulvus,as a closely related wild species of sugarcane,has excellent traits such as drought resistance,cold resistance,barren tolerance and high hammer degree,and is an excellent parental material which is of great use in cross breeding of sugarcane.In order to further study the drought tolerance of the progeny materials containing cane fescue lineage,and also to provide scientific basis for the use of these materials in sugarcane drought tolerance breeding,19 BC₁F₁materials and three parental materials obtained from the backcross between Dianzhe 01-58 and Erianthus fulvus were analysed and comprehensively evaluated at the agronomic traits,physiological and biochemical,photosynthetic characteristics and molecular levels after drought stress:（1）Agronomic traits of the materials decreased after drought stress compared to the overall level of the control,indicating that drought stress can cause irreversible damage to the plants despite being applied at the seedling stage.Chromosome number was strongly associated with stem diameter,internode length and leaf width with abundant genetic potency.（2）The correlation between all the indicators was greater or lesser,among which cell membrane permeability and superoxide dismutase activity were significantly positively correlated with drought tolerance,while relative water content was highly significantly negatively correlated with drought tolerance,indicating that the stronger the cell membrane permeability,the higher the superoxide dismutase activity and the lower the relative water content,the stronger the drought tolerance of the material under drought stress.Based on the comprehensive evaluation of the drought tolerance of the materials based on the physiological and photosynthetic indexes,the 22 test materials were classified into three categories:highly drought tolerant,moderately drought tolerant and non-drought tolerant,among which the drought tolerance of Erianthus fulvus was the strongest,the drought tolerance of Yacheng 89-9 was the weakest,the drought tolerance of the offspring materials was the strongest in 16-5 and the weakest in 16-6.The further analysis revealed that the lower the number of chromosomes,the more drought-tolerant the material was,which could provide a certain theoretical basis for the drought tolerance of future generations.（3）From the transcriptome data of the extreme materials,we annotated 19216 genes on the KEGG database,23914 genes in GO,14367 genes in KOG and 23322 genes in Pfam.The Venn diagram comparison analysis identified 1584 differential genes specific to the most drought tolerant materials.（4）The transcription factor analysis of the extreme materials revealed that the RLK,b HLH and MYB families have important roles in drought tolerance in sugarcane,and it is important to investigate the subsequent functions and regulatory mechanisms of the related transcription factors,if the genes in these gene families can be cloned and transferred into sugarcane,it may be possible to improve its drought tolerance and produce new materials.