Comparação de parâmetros de crescimento e de desenvolvimento de dois biótipos de arroz vermelho com genótipos de arroz irrigado

Abstract

GROWTH AND DEVELOPMENTAL OF RED AND PAD RICE GENOTYPESThe characterization growth and development of red rice biotypes may help controll strategies, the enhancement of competitiveness of cultivated rice with this weed and breeding programs. The objective of this is study was to quantity some growth and development parameters of two red rice biotypes as compared to irrigated genotypes. A field experiment was carried out at Santa Maria, Rio Grande do Sul State, Brazil, during the 2004/2005 growing season with five sowing dates. The experimental design was a completely randomized with four replication in a two factorial arrangement (genotypes and sowing dates). The experimental unity was a 12 L pot with 10 plants. The genotypes used were: IRGA 421, IRGA 416, IRGA 417, IRGA 420, BR-IRGA 409, BRS 7 TAIM, EPAGRI 109, EEA 406, a hybrid, and two red rice biotypes (awned yellowhull-AVCAA, and awned blackhull-AVCPA). The date of major developmental stages in the COUNCE scale, leaf area, panicle length, plant height, phyllochron, main culm final leaf number, and tillering were measured in five plants per pot. Red rice biotypes usually had an intermediate developmental cycle compared to cultivated rice genotypes, with AVCAA having a longer cycle than AVCPA. Red rice biotypes had greater leaf area, greater height, greater panicle length and greater phyllochron, than modern rice genotypes. Tillering of red rice varied according to the sowing date.

Características morfoagronômicas de dois genótipos arroz vermelho em cultivo inundado

“…Em ensaio conduzido na região Nordeste, no ano de 2005, por Rangel et al (2006) observou-se altura de 85 cm para a variedade SCSBRS Tio Taka, valor 16 cm inferior ao encontrado neste experimento. A maior estatura confere, à planta, grande capacidade de competição pelo recurso de radiação solar mas maior susceptibilidade ao acamamento (Streck et al, 2008). Reduções na altura da planta em variedades de arroz vermelho podem ser obtidas em programas de melhoramento vegetal.…”

“…A maior estatura das plantas de arroz vermelho confere, a esta planta daninha, grande capacidade de competição pelo recurso de radiação solar. Além disso, maior estatura concede maior susceptibilidade ao acamamento, um aspecto prejudicial a mais em lavoura de arroz (Streck et al, 2008).…”

“…Na comparação de uma variedade de arroz vermelho com 15 de arroz branco em regime de irrigação por inundação com lâmina d'água permanente, observou-se praticamente o mesmo potencial de produção entre variedades. As características intermediárias de crescimento e desenvolvimento de genótipos de arroz vermelho entre cultivares modernas de porte baixo e ciclo curto e cultivares tradicionais, de porte mais elevado e ciclo longo, refletem a condição de planta daninha em constante processo de evolução (Streck et al, 2008). Brunes et al (2007) detectaram, em seu experimento, fluxo gênico a 10 m de distância entre o arroz vermelho e o arroz cultivado, o que ajuda a explicar o alto potencial de contaminação em áreas de cultivo comercial.…”

Potential of plant species for bioremediation of soils applied with imidazolinone herbicides

“…Among the weeds, there is red rice as the most problematic, causing losses of up to 20% in grain yield, if no control method is adopted (Marchesan et al, 2004). Besides being considered a difficult to control species, because it possesses morphological and physiological similarities with cultivated rice, herbicides traditionally used to control red rice have been shown to be ineffective (Santos et al, 2007;Streck et al, 2008).…”

Rice root growth and development in competition with weedy rice

“…By exploiting basically, the same ecological niche, weedy and cultivated rice genotypes compete for the same resources in time and/or space (Fleck et al, 2008). However, a number of distinct traits, such as early vigor, greater tiller emission and height (Abraham and Jose, 2014), give weedy rice a competitive advantage, primarily from sunlight (Streck et al, 2008). Solar radiation regulates the physiological and biophysical processes of plants (Yang et al, 2013), acts as an environmental signaler (Jiao et al, 2007), and is a significant source of competition for several weed species (Rizzardi et al, 2001).…”