Influence of Sowing Time on the Establishment and Development of Flooded Rice

Abstract

There is a great regional climatic variation in RS, the largest rice producing state in Brazil, which causes different responses in grain yield, making the sowing time, the determining factor of the annual production of this cereal. This study aimed to evaluate flooded rice cultivars with different development cycles as a function of sowing date and the agroecological sub-region of RS. Two experiments were carried out in the Central and Southern region of RS, evaluating grain yield in eight sowing dates (from 09/01 to 12/15) with cultivars from four different maturation cycles: super short, short, medium and long. The thermal sum was quantified for the main stages of the crop, as well as the speed of establishment at all dates. Early sowing (until 10/01) can harm the initial stand and the establishment of the culture is delayed according to the anticipation of sowing. The difference in the need for thermal sum accumulation between cycles is more contrasting from the emergence- panicle differentiation subperiod and the sowing date for RS, differs according to the cycle being 09/15 to 10/01 for long cultivars, 10/01 to 10/15 for medium, 10/1 to 11/15 for short and 11/15 for super short.

Keywords
IRGA 424; photoperiod; bioclimatic; cold