Decreased Night Temperature Affects Development And Grain Yield Only In Cold-Susceptible Rice (Oryza Sativa) Plants

It is largely known that low temperature stress can affect rice (Oryza saliva L.) development and yield. However, most studies have focussed on unique and uninterrupted cold treatment, which is not representative of cold conditions for early sowing in temperate and subtropical areas where cold nights are followed by warm days during early vegetative stages. In order to elucidate whether rice plants could recover from the damages caused by repetitive cold nights, we submitted a cold-tolerant (CT) and a cold-sensitive (CS) indica genotype to 28 cold nights (10 degrees C) followed by warm days (26 degrees C) and analysed the developmental and productivity traits of plants cultivated in greenhouse and field conditions. While CT plants were able to recover from cold damage without significant development and seed production penalties, CS plants were affected, presenting lower results in plant height, tiller number, number of seeds per plant, % of full seeds per plant, grain length and area, weight of 1000 full grains, and grain weight per plant, with a grain yield reduction of 82% and 30% when cultivated in greenhouse and field conditions, respectively. Such data on sowing period, night temperatures and the cold response of the rice cultivar used are important for the producer to consider.