Growth and development of sourgrass based on days or thermal units

Abstract

-This work was carried out with the objective of evaluating growth and development of sourgrass (Digitaris insularis) based on days or thermal units (growing degree days -GDD). Two independent trials were developed aiming to quantify the species' phenological development and total dry matter accumulation in increasing or decreasing photoperiod conditions. Plants were grown in 4 L plastic pots, filled with commercial substrate, adequately fertilized. In each trial, nine growth evaluations were carried out, with three replicates. Phenological development of sourgrass was correctly fit to time scale in days or GDD, through linear equation of first degree. Sourgrass has slow initial growth, followed by exponential dry matter accumulation, in increasing photoperiod condition. Maximum total dry matter was 75 and 6 g per plant for increasing and decreasing photoperiod conditions, respectively. Thus, phenological development of sourgrass may be predicted by mathematical models based on days or GDD; however, it should be noted that other environmental variables interfere on the species' growth (mass accumulation), especially photoperiod.Keyword: Digitaria insularis, growing degree days, phenology, dry matter, biology. RESUMO -Objetivou-se neste trabalho avaliar o crescimento e o desenvolvimento do capim-amargoso (Digitaria insularis) com base em dias ou unidades térmicas acumuladas (graus-dia -GD). Para isso, dois experimentos independentes foram realizados visando quantificar o desenvolvimento

Growth and Development of Digitaria insularis Biotypes Susceptible and Resistant to Glyphosate

“…These results corroborate those obtained by Marques et al (2014) in D. insularis plants without distinction of glyphosate resistance. However, in the study conducted by Machado et al (2006), a slow growth rate was observed until 45 DAE, and the maximum accumulated total dry matter of D. insularis was 30.7 g per plant at 105 DAE.…”

“…These models can be used to understand the influence of biological, ecological, genetic and management factors on the likelihood of selection for glyphosate-resistant weeds in agricultural lands and in the development of strategies to mitigate these risks by means of simulation models (Neve, 2008;Marques et al, 2014).…”

“…The growth pattern of D. insularis plants was investigated by Machado et al (2006) and Marques et al (2014). However, these authors did not compare the biological cycle of glyphosate-susceptible and resistant biotypes.…”

Dry Matter and Macronutrient Accumulation in Digitaria insularis Biotypes Susceptible and Resistant to Glyphosate

“…The D. insularis species is a perennial plant that is highlighted by the formation of rhizome and clumps, with slow initial growth and posterior exponential dry matter accumulation (Machado et al, 2008;Carvalho et al, 2013;Marques et al, 2014). Such factors is related to its aggressiveness as a weed species and may provide high competitiveness to the species for natural resources, among them, nutrients present in the soil.…”

Crescimento e desenvolvimento, resistência múltipla aos herbicidas inibidores da EPSPS-ALS e alternativas em pós-emergência para controle de <i>Amaranthus palmeri</i> (S.) Wats

“…Assim sendo, ao menos em teoria, uma planta é capaz de crescer sem, necessariamente, desenvolver-se e vice-versa (MARQUES et al, 2014;MACHADO et al, 2014). Assim sendo, para estimar o crescimento e o desenvolvimento vegetal, além da descrição das fases fenológicas, torna-se fundamental a mensuração da massa de matéria seca das diferentes estruturas da planta (ANDRADE et al, 2009;TAKANO et al, 2016).…”