Yield as affected by water availability and plant type in upland rice

Abstract

The relationship among yield, its components and some selected morphophysiological characteristics were determined using 49 cultivars of contrasting plant type, submitted or not to water stress. It was found that water availability affected the relationship between yield and other plant characteristics. Under water stress the most relevant associations with yield were developed by days to flowering, percent of filled grains and leaf angle. When water was supplemented, yield was affected posltively by panicles per square meter, leaf area index at flowering and negatively by leaf width. Those observations can be applied as a selection criteria in upland rice breeding. There are regions in Brazil considered as favored concerning water distribution. For this particular condition it seems appropriate to develop a medium height, medium tillering, lodging resistant cultivars. For regions of high climatic risk, adequate growth cycle and drought resistance are priorities over plant type improvement. The association between yield and leaf angle should be better clarified and may be a way to improve plant type even for the latter situation.