Bhat, SumangalaManel, Dapanage2019-09-232019-09-232015-09http://krishikosh.egranth.ac.in/handle/1/5810128947Moisture stress causes significant yield loss in all crops and sugarcane is also not an exception. Studying the diversity among the commercial sugarcane varieties and molecular basis of stress tolerance is useful while developing moisture stress tolerant sugarcane varieties. Fifty-two commercial sugarcane varieties were subjected for moisture stress by withholding the irrigation and grouped into different tolerance categories based on the time taken for appearance of wilting symptoms. Two (Co 775 and Co 99010) out of 52 varieties showed wilting symptoms early (4 days after withholding the irrigation) were grouped as highly susceptible and three varieties namely Co 94008, CoT 8201 and ISH 100 showed very late wilting symptoms (12 days) were grouped as highly tolerant. Varieties showed significant variation in the traits such as proline content, EC, RWC and chlorophyll content and positive correlation were observed between RWC and chlorophyll content under moisture stress condition with time taken for appearance of wilting symptoms. Molecular diversity among 52 commercial varieties studied using 54 SSR markers revealed higher (58 per cent) similarity among the varieties. The transcriptome profile of a moisture stress tolerant sugarcane variety, Co 94008, under moisture stress were studied by total RNA sequencing in Illumina Solexa NGS platform and more than 17000 transcripts were identified. Among them, 1143 transcripts showed significant differential expression under moisture stress and expressions of 487 were found to be up-regulated and 656 were down-regulated. Of the top 20 up-regulated transcripts, nine showed more than 100 fold expression and expressions of sixteen genes were highly down regulated (> -5 folds) under moisture stress. Expression profiles of TFs generated using semi qRT-PCR followed by qRT-PCR revealed significant differential expression of nine TF genes among the susceptible and resistant varieties under different levels of moisture stress. The TF, bZIP was significantly up regulated in resistant variety under both moderate and sever stress conditions than the susceptible variety.ennullThesis