Growth of the crabgrass species Digitaria ciliaris and Digitaria nuda

Abstract

-The aim of this research paper was to compare the growth of D. ciliaris and D. nuda crabgrass species under non-competitive conditions. To this end, two experiments were conducted, one from March -July 2010 and the other from February -June 2011. The experimental design of both trials was completely randomized making a factorial (2 seasons x 2 species crabgrass x 12 evaluation periods) with four replications. Assessments began at 15 days after sowing (DAS), and repeated weekly until 92 DAS. The variables evaluated were total dry matter (roots+leaves+stems), leaf area, leaf number and tiller. The results were submitted to analysis of variance and the absolute growth rate, relative growth rate and leaf area ratio were calculated using the means, which were adjusted regression models. The crabgrass species were significantly different in leaf area, leaf number, tiller number and dry matter per plant. D. ciliaris for all variables was statistically higher than D. nuda. Regarding the speed at which the growth of the species occurred, the absolute growth rate and relative growth rate of D. ciliaris was also greater than D. nuda. In addition, D. ciliaris also had a lower leaf area ratio indicating greater efficiency in converting light energy into carbohydrates. It can be concluded that D. ciliaris has a higher growth rate in conditions where there is no limitation of nutrients and water availability in relation to D. nuda, mainly due to D. ciliaris have greater leaf area, number of leaves and dry matter accumulation per plant.

Periods of weed interference in maize crops cultivated in the first and second cycles

“…The presence of these plants leads to a high utilization of environmental resources, as they can accumulate biomass for up to 73 days after emergence, which has led to drastic interference up to 40% in developing maize (SOUZA et al, 2012). Table 5.…”

Growth Analysis of Chloris elata

“…However, at the end of the cycle, culms had greater participation in the accumulation of mass, with 61.5%, compared to other parts of the plant (19.2% for leaves, 14.4% for roots and 8.1% for inflorescences). These percentages indicate that, at more advanced development stages, In another study, Digitaria ciliaris plants had larger leaf area, number of leaves and tillers and, consequently, higher dry matter during the experimental period, in relation to D. nuda plants (Souza et al, 2012). However, the species reached 50% of their maximum produced dry matter only at 57 and 58 DAS, respectively.…”

“…The absolute growth rate of D. ciliaris and D. nuda, annual cycle grasses, increased slowly during the initial phase of the experimental period, reaching their maximum value at 71 and 73 DAS, respectively (Souza et al, 2012). This contributed to a greater accumulation of mass per plant for D. ciliaris, compared to D. nuda, also justified by the higher relative growth rate of D. ciliaris at the early stage of the cycle.…”

“…This contributed to a greater accumulation of mass per plant for D. ciliaris, compared to D. nuda, also justified by the higher relative growth rate of D. ciliaris at the early stage of the cycle. The growth rate is an important characteristic used to describe plants with different ecological strategies (Souza et al, 2012).…”

Aspectos da biologia, suscetibilidade diferencial e eficácia de herbicidas alternativos ao glyphosate no manejo de populações de capim-pé-de-galinha (<i>Eleusine indica</i> L. Gaertn.)

“…A adaptabilidade ecológica de biótipos resistentes pode ser afetada, em função de alguns mecanismos que conferem a resistência, como por exemplo, a translocação reduzida, que poderia resultar em menor capacidade de acúmulo de matéria seca, sementes e raízes (PRESTON et al, 2009). Uma das formas de avaliar diferenças na adaptabilidade de diferentes populações ou espécies é a construção de curvas de crescimento (CHRISTOFFOLETI; WESTRA; MOORE, 1997;CARVALHO, 2006;SOUZA et al, 2012;.…”