Impact of increasing mean air temperature on the development of rice and red rice

Isabel Lago,Cleber Maus Alberto,Gizelli Moiano De Paula,Felipe Brendler Oliveira,Nereu Augusto Streck

doi:10.1590/s0100-204x2008001100001

Isabel Lago, Cleber Maus Alberto + Show 3 more

Open Access

https://doi.org/10.1590/s0100-204x2008001100001

Copy DOI

Abstract

The objective of this study was to assess the development response of cultivated rice and red rice to different increases in minimum and maximum daily air temperatures, in Santa Maria, Rio Grande do Sul State, Brazil. One hundred years climate scenarios of temperatures 0, +1, +2, +3, +4, and +5ºC, with symmetric and asymmetric increases in minimum and maximum daily air temperatures were created, using the LARS-WG Weather Generator, and a 1969-2003 database. Nine cultivated rice genotypes (IRGA 421, IRGA 416, IRGA 417, IRGA 420, BRS 7 TAIM, BR-IRGA 409, EPAGRI 109, EEA 406 and a hybrid), and two red rice biotypes (awned black hull-ABHRR, and awned yellow hull-AYHRR) were used. The dates of panicle differentiation (R1), anthesis (R4), and all grains with brown hulls (R9) were estimated with a nonlinear simulation model. Overall, the duration of the emergence-R1 phase decreased, whereas the duration of the R1-R4 and R4-R9 phases most often increased, as temperature increased in the climate change scenarios. The simulated rice development response to elevated temperature was not the same, when the increase in minimum and maximum temperature was symmetric or asymmetric.

Highlights

There is a major consensus among scientists, except for some minor disagreements, that climate is changing and air temperature is raising due to increasing concentrations of CO2 and other atmosphere greenhouse gases (Weiss et al, 2003; Kerr, 2005; IPCC, 2007)
A trend of increasing negative deviations was observed in the duration of the vegetative (EM–R1) phase, for increasing mean air temperature scenarios, for both symmetric and asymmetric increase in minimum and maximum temperature (Tables 3, 4 and 5)
The shortest EM–R1 phase was simulated for the asymmetric increase – based scenarios, and deviations increased with the length of this phase

Summary

Introduction

There is a major consensus among scientists, except for some minor disagreements, that climate is changing and air temperature is raising due to increasing concentrations of CO2 and other atmosphere greenhouse gases (Weiss et al, 2003; Kerr, 2005; IPCC, 2007). There are reports that the 90’s was the warmest decade in the last millennium (Kerr, 2005), and projections indicate that it is very likely that mean global temperature will increase from 1.1 to 6.4oC by the end of this century, in several locations, including Brazil (IPCC, 2007). Agroecosystems are likely to be affected by the projected climate change (IPCC, 2007), and their responses will cause considerable impacts on public policy at national and international levels. The State of Rio Grande do Sul is the largest Brazilian rice producer, with an average yield of 6.7 Mg ha‐1, in about one million hectares of flood‐irrigated fields (Instituto Rio Grandense do Arroz, 2007). Red rice (Oryza sativa L.) is one of the top weeds and it has caused considerable yield reduction in paddy rice fields worldwide (Noldin et al, 1999; Marchezan et al, 2004)

Objectives

Methods

Results

Conclusion