Int.J.Curr.Microbiol.App.Sci (2018) 7(1): 1103-1109 1103 Original Research Article https://doi.org/10.20546/ijcmas.2018.701.133 Cold Tolerance at Germination and Seedling Stages of Rice: Methods of Evaluation and Characterization of Thirty Rice Genotypes under Stress Conditions Javeed A. Lone 1* , M. Nisar Khan 2 , M. Ashraf Bhat 1 , Asif B. Shikari 3 , Shabir H. Wani 4 , Najeeb R. Sofi 4 , M. Imran Khan 5 and Rayees A. Lone 1 1 Division of Genetics and Plant Breeding, FoA, Sher-e- Kashmir University of Agricultural Science and Technology of Kashmir, Wadura Sopore-193201, Jammu and Kashmir, India 2 Dryland Agriculture Research Station, Budgam, India 3 Division of Plant Biotechnology, Sher-e- Kashmir University of Agricultural Science and Technology, Shalimar-190025, India 4 Sher-e-Kashmir University of Agricultural Science and Technology Shalimar, Rice Research Station (MRCFC) Khudwani, India 5 Division of Agri-Statistics, Sher-e- Kashmir University of Agricultural Science and Technology, Shalimar-190025, India *Corresponding author ABSTRACT International Journal of Current Microbiology and Applied Sciences ISSN: 2319-7706 Volume 7 Number 01 (2018) Journal homepage: http://www.ijcmas.com Rice is one of the most important staple foods among the cereal crops for half of the human population. Unlike other cereals such as wheat and barley, rice plants are susceptible to cold stress, which causes decrease in productivity, especially in regions where the indica subspecies is cultivated. Low temperatures can have direct impacts on rice plants during germination, vegetative growth, and reproductive stages. This study aims to identify a suitable technique to estimate rice (Oriza sativa L.) cold tolerance at the germination stage and identify the variability among 30 rice genotypes. Cold tolerance was evaluated by two methods: in method I, rice seeds were kept and germinated under two conditions; 28 days in 13°C and seven days in 28°C; in experiment II, seedlings were kept at 72 hours 96 hours at 13°C and again 72 hours at 28°C. In experiment I percentages of reduction in radicle and coleoptile length and germination percent and percent decline in germination were measured. In experiment II coleoptiles growth radical regrowth after the cold period were measured. Results showed that low temperature effects in both experiments were varied among studied genotypes. Highest germination was achieved in SKAU-402 fallowed by SI-6, K-332, SI-5 and SI-3 with less percent decline in germination that is, 0.13, 0.17, 0.24 and 0.32 at 13ºC. Percentage of coleoptiles growth by low temperature (13ºC) was varied from 13.8 to 86.6%. In experiment II, radicle regrowth values varied from 2.0 to 12.0 mm, and SI-6,-SI-5, Kamad, SKAU-402 and K332, were the genotypes with high radicle regrowth. Keywords Abiotic stress, Controlled situation, Coleoptile growth, Radical regrowth, Low temperature Accepted: 10 December 2017 Available Online: 10 January 2018 Article Info