Phenotyping and morpho-physiological behavior of rice genotypes under water deficit

Abstract

Given the current climate change, understanding and selectimg of the drought tolerant genotypes become extremely important. The upland rice is sensitive to climatic conditions and it is damaged by the occurrence of water deficit. Once the variability has been found for drought tolerance, upland rice crop can be studied and worked by breeders in order to solve the problem. Thus, the objective of this work was to fine phenotype upland rice genotypes, contrasted by behavior under water deficit, using analysis of morpho-physiological characteristics, and phenotypic correlations estimation between index of response variation from evaluated characters. For this, two trials were conducted using six previously selected genotypes, and stress start was at panicle initiation. A trial was conducted in a randomized block design, with three repetitions and two water treatments, irrigated (IRR) and stressed (STR), at Embrapa Rice and Beans, Santo Antônio de Goiás, Brazil. And a second one, at CIRAD, Montpellier France, was conducted in a completely randomized design, with three repetitions and two water treatments, IRR and STR. Several characters were evaluated and used for fine phenotyping plant development, until panicle emergence, determining in this phase water stress end. To better understand data obtained, were done analyzes of variance, means grouping by Scott-Knott test, orthogonal contrasts and phenotypic correlations between response index to evaluated characters were performed. Through the analyzes was possible to conclude that CIRAD 409 presents potential drought tolerance, without behavior change and a significant increase in water use efficiency for dry weight production under water stress. The spikelet number reduction is strongly related to panicle branch number reduction, but not related with panicle length reduction. The flag leaf width and length reduction is directly related with panicle spikelet number of the main stem.