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Pakistan Journal of Biological Sciences
  Year: 2003 | Volume: 6 | Issue: 12 | Page No.: 1070-1076
DOI: 10.3923/pjbs.2003.1070.1076
Effect of a Range of Constant Temperatures on Germination of Fifteen Bangladeshi Rice (Oryza sativa L.) Cultivars
M.G. Ali, R.E.L. Naylor and S. Matthews

Abstract:
Germination of 15 rice cultivars were investigated on a temperature gradient plate with a range of temperatures 13.7-37.3 °C to identify rice genotypes tolerant of low temperature which would facilitate in cultivar selection for winter sown rice (Boro rice) in Bangladesh. The results demonstrated a plateau of more than 90% final germination between 18 and 33 °C for eleven cultivars. Three cultivars had a plateau of less than 90% germination. At the lowest temperature seven cultivars achieved 80% germination whereas lower quality cultivars showed less than 8% germination. The rest of cultivars were intermediate with about 30-50% germination. The rate of germination (the reciprocal of median germination time) for all cultivars increased linearly from 13.7 up to 30.9 °C and then declined rapidly between 30.9 and 37.3 °C. At optimum temperature cultivars with lower quality seed sample (BR1, KS, KG and BR30) had the lowest rates of germination along with cv. BR5. Rates of germination at higher temperatures (20.1 and 30.9 °C) were significantly related to the rates of germination at lower temperature (13.7 and 15.8 °C). The base temperature differed little between cultivars (range 12.6–13.9 °C) and optimum temperature ranged from 29.9 to 33.5 °C (mean 32.1 °C). Thermal time to achieve 50% germination at sub-optimal temperatures ranged from 526 to 1667 °C h and differed significantly between cultivars. Cultivars with lower quality seeds and BR5 required than above 900 °C h. The application of these findings to the development of routine methods to identify rice genotypes able to germinate at lower temperature is emphasized. Measurements of rates of germination at higher temperatures (20 and 30 °C) could provide a relatively rapid screening method indicative of low temperature performance for large numbers of genotypes.
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How to cite this article:

M.G. Ali, R.E.L. Naylor and S. Matthews, 2003. Effect of a Range of Constant Temperatures on Germination of Fifteen Bangladeshi Rice (Oryza sativa L.) Cultivars. Pakistan Journal of Biological Sciences, 6: 1070-1076.

DOI: 10.3923/pjbs.2003.1070.1076

URL: https://scialert.net/abstract/?doi=pjbs.2003.1070.1076

 
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