Evapotranspiration and grain yield of upland rice as affected by water deficit

Abstract

A B S T R A C TTo achieve an accurate phenotyping for drought tolerance, it is important to control water stress levels and timing. This study aimed to determine water use by upland rice plants during periods of irrigation withholding and its relationship with grain yield in order to increase the efficiency of this phenotyping. Two experiments were carried out in a randomized block design in which six water treatments (irrigation withholding for periods of 2, 4, 6, 8, 10 and 12 days) were compared, with four replicates. In the first experiment, treatments were applied at the R3 stage (panicle exsertion) and, in the second, at the R5 stage (beginning of grain filling). The amount of water evapotranspired was determined by the difference between the soil water storage at the beginning and at the end of irrigation withholding periods, from the surface to 80-cm depth. Evapotranspiration of upland rice from R3 stage was higher compared to that observed from R5 stage, when subjected to similar irrigation withholding periods in both growth stages. Rice grain yield is more sensitive to irrigation withholding imposed from R5 stage than from R3 stage.Evapotranspiração e produtividade do arroz de terras altas afetadas pela deficiência hídrica R E S U M O Para se obter fenotipagem acurada para tolerância à deficiência hídrica, é importante controlar o nível de estresse hídrico e a época de sua aplicação. Este trabalho objetivou determinar o uso de água pelas plantas de arroz de terras altas durante períodos de supressão da irrigação e sua relação com a produtividade de grãos, para aumentar a eficácia desta fenotipagem. Foram conduzidos dois experimentos no delineamento de blocos ao acaso e comparados seis tratamentos hídricos (supressão da irrigação por períodos de 2, 4, 6, 8, 10 e 12 dias) com quatro repetições. No primeiro experimento os tratamentos foram aplicados no estádio R3 (emissão das panículas) e no segundo, no estádio R5 (início do enchimento de grãos). A água evapotranspirada foi determinada pela diferença entre o armazenamento de água no solo no início e no fim dos períodos de supressão da irrigação, da superfície até 80 cm de profundidade. A evapotranspiração do arroz no estádio R3 foi mais alta comparada com a observada no estádio R5, quando submetida a período similar de supressão da irrigação em ambos os estádios. A produtividade do arroz foi mais sensível à supressão da irrigação imposta a partir do estádio R5 do que do estádio R3.

Genetic Behavior of Some Root and Grain Quality Traits Under Water Deficit and Normal Conditions in Rice (Oryza Sativa L.)

“…grain length in cross II and grain shape in both crosses exhibited highly significant negative heterosis as a deviation from midparents under both water deficit and normal conditions. Similar results were reported earlier by Abd El-Lattef et al (2008), Ganapathy and Ganesh (2008), Abd-Allah (2009), Hassan et al (2011), Mall et al (2011), Concepcion et al (2015 and Guimaraes et al (2016).…”

“…Additive gene effects can be exploited in early generations because the dominance effects were also non-significant and lower in magnitude than these additive effects. Similar results were reported by Shehata et al (2004), Manickavelu et al (2006), Kumar et al (2006, Hassan et al (2011), Hijam et al (2012, Ravikumar et al (2014) and Guimaraes et al (2016).…”

“…The present investigation was carried out at Sakha Agricultural Research station Farm, Sakha, Kafr El-Sheikh, Egypt, during 2014, 2015and 2016 seasons to study the genetic behavior of some root and grain quality traits in rice under water deficit and normal conditions, i.e., root length (cm), root volume (cm 3 ), number of roots/ plant, root/ shoot ratio, grain length (mm), grain shape (mm), hulling %, milling %, head rice % and amylose content %.…”

Genetic Behavior of Some Root and Grain Quality Traits Under Water Deficit and Normal Conditions in Rice (Oryza Satival.)

“…,Abd-Allah (2009),Hassan et al (2011),Mall et al (2011),Concepcion et al (2015) andGuimaraes et al (2016).…”

Morphological and Physiological Traits of Upland Rice Cultivars Affected by Water Deficit

“…Therefore, the Douradão cultivar showed lower transpiration in well-watered conditions and under moderate water deficit and did not differ from the BRS Soberana in severe water regimes. Guimarães et al (2016b) also found that rice transpiration decreased with water deficit and Cabuslay et al (2002) observed that rice cultivars with moderate tolerance to water stress showed higher relative transpiration rates, which confirms the greater tolerance of the Douradão cultivar to water stress in relation to the BRS Soberana.…”