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20161
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Subject: Plant Breeding and Genetics × Author: Brar, Amrinder Singh × End date: 2020 × Start date: 2000 × Type: Thesis ×
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    Physiological and Molecular Characterization of Cold Tolerant Sugarcane Germplasm
    (Punjab Agricultural University, Ludhiana, 2016) Brar, Amrinder Singh; Sandhu, Surinder K
    In the state of Punjab, the reasons for low productivity of sugarcane are primarily the adverse agro-climatic conditions prevailing in the region. Sugarcane is a cold sensitive plant and its active growth period in Punjab is confined to six to seven months from April to October. Research on cold tolerance is of vital significance as chilling stress affect the quality of mid-maturing cane varieties in sugarcane crop and sprouting of ratoon crop. Conscious efforts were made to select cold tolerant genotypes from huge germplasm assemblage of 1200 genotypes. The selected set of 24 tolerant genotypes was extensively assessed for physio-biochemical parameters in reference to 24 sensitive genotypes as check under natural cold conditions. The significant differences among tolerant and sensitive genotypes for proline, chlorophyll, total soluble sugars, free amino acids, relative water content and carotenoids before and after cold stress elucidated the role of these parameters in imparting cold hardiness. Based on agronomic profiling, cryo-protectant physio-biochemical traits and cane quality, genotypes CoJ 88, ISH 260, ISH 313, ISH 260, F 110/09, F 228/09, CoS 03261 and CoS 03222 were selected as cold tolerant genotypes having high economic potential and suggested for their utilization in breeding for cold tolerance. Visual screening of genotypes, although needed validation can be authentically used for selection of cold tolerance. Expressed Sequence Tags (ESTs), sequences from public domain, reported to be upregulated in response to cold stress were blasted with sorghum genome and primers were designed using corresponding genomic region encoding proteins of Heat Shock Proteins (HSP) and No Apical Dominance (NAM). Molecular markers HSP Sorghum3 and NAM Soghum2 exhibited allelic size polymorphism between tolerant and sensitive genotypes. The two sequence tagged microsattelite markers (STMS) viz., NKS 45 and NKS 46 were found to be associated with high and low sugar content, respectively. These identified markers could be of high utility to screen a large breeding population for high sucrose content at initial growth stage in long duration sugarcane crop. The study could serve a strong foundation to initiate breeding for cold tolerance in sugarcane.