Low temperatures that occur during the cultivation of rice in the Southern region of Brazil cause reductions in to the yield and quality of the rice grain. Genotypes tolerant to low temperatures would be an alternative to minimize these problems. In the present work cold tolerance was evaluated in rice families (M4 generation) in the vegetative and reproductive phases, in order to identify possible genetic variability. For the evaluation in the vegetative stage, 10 seeds from each family were placed in cell trays and kept at 13 ºC for 10 days in controlled chamber with 12 hour day light. The evaluation at the reproductive stage consisted of the application of low temperature at anthesis, by a stress of 15 ºC for 7 days. The results suggest that in the vegetative phase, 6 families presented 0-20% reduction in stature, showing a high degree of tolerance. For the reproductive phase there were no families showing higher tolerance than the tolerant control.
Oryza sativa L.; plant breeding; induced mutation
