Identification of Rice Genotypes Tolerant to Cold Temperature at Seedling Stage

In Chhattisgarh, rice is also grown during summer season in about 2 lakh hectares, mainly in areas with canal irrigation. Usually the productivity during summer is higher than Kharif season. However, in this season the sowing is usually done in the month of December or January during which the minimum temperature is low, which results in poor seedling establishment, stunting, yellowing and mortality. Many species of tropical or subtropical origin are injured or killed by non-freezing low temperatures, and exhibit various symptoms of chilling injury such as chlorosis, necrosis, or growth retardation. In contrast, chilling tolerant species are able to grow at such cold temperatures. To overcome the problem of damage caused by low temperature, rice breeders have been making efforts to develop more cold-tolerant cultivars mainly at seedling stage. In this study, 25 different genotypes, including commonly grown varieties, were screened under field condition during December-January 2011 and 2012 during seedling stage at Research cum Instructional Farm, IGKV, Raipur (C.G.). The minimum temperature during this period was below 10°C at-least for a 12 days. Lines were evaluated on 1–9 score according to SES of rice, IRRI. Genotypes Samleshwari, Annadaand R-RF-75 showed dark green leaf colour with score 1, while Sahbhagidhan and IR-84887-B-15 exhibited yellowing of leaf with score of 9 and 7, respectively. The result of this study is discussed in context of breeding value and practical significance from farmers'point-of-view.