Perfilhamento como característica mitigadora dos prejuízos ocasionados ao milho pela desfolha do colmo principal

Abstract

Resumo -O objetivo deste trabalho foi verificar se os perfilhos podem mitigar os prejuízos ocasionados pela desfolha do colmo principal em milho. Os experimentos foram implantados em Lages, SC, em 20/10/2006 e 31/10/2008. O delineamento experimental utilizado foi o de blocos ao acaso, com parcelas subdivididas. Na parcela principal, foram testados dois destinos dos perfilhos: manutenção até a colheita e remoção quando o colmo principal apresentava nove folhas expandidas (V9). Nas subparcelas, avaliaram-se quatro épocas de desfolha do colmo principal: V9, V15 (quinze folhas expandidas), VT (pendoamento) e folhas preservadas até a colheita. Avaliou-se o híbrido P30F53, à densidade de 55 mil plantas por hectare. Determinaram-se: a produtividade total, a do colmo principal e a dos perfilhos. As desfolhas realizadas em V15 e VT diminuíram a produtividade, em comparação ao tratamento sem desfolha, independentemente do destino dos perfilhos. Quando o milho foi desfolhado em V15 e VT, a produtividade total das parcelas em que os perfilhos foram mantidos foi maior do que daquelas em que eles foram removidos. Isto indica que os perfilhos foram benéficos ao colmo principal do milho, quando houve restrições à produção de carboidrato oriundas da perda de área foliar próximo do florescimento.Termos para indexação: Zea mays, perfilho, massa de grãos, produtividade. Tillering as a trait to mitigate damages caused to maize by the main stem defoliationAbstract -The objective of this work was to verify if tillers can mitigate damages caused by the main stem defoliation in maize. The experiments were set up in Lages, SC, Brazil, on 10/20/2006 and 10/31/2008. The experimental design was a randomized block with split plots. Two tiller destinations were tested in the main plots: tillers preserved until harvesting, and tillers removed when the main stem had nine expanded leaves (V9). Four main stem defoliation times were assessed in the split plots: V9, V15 (15 expanded leaves), VT (tasseling), and leaf maintenance until harvesting. Hybrid P30F53 was tested at 55 thousand plants per hectare. Total grain yield, tiller grain yield and main stem grain yield were determined. Defoliations performed at V15 and VT decreased total productivity, in comparison to the control, regardless of tiller destination. When the main stem was defoliated at V15 and VT, plots where tillers were kept promoted higher total grain yield than those where tillers were removed. This indicates that tillers were instrumental to maize main stem when there were restrictions to the production of carbohydrates due to leaf area loss close to flowering.Index terms: Zea mays, tiller, grain mass, productivity. IntroduçãoOs perfilhos são ramificações laterais que se desenvolvem a partir de gemas axilares dos nós abaixo da superfície do solo. São estruturas utilizadas pelas plantas da família Poaceae como estratégia para compensação de espaços vazios dentro da comunidade (Li et al., 2003;Almeida et al., 2004). Nas espécies em que o perfilhamento é comum, como o trigo, o arroz ...

Induced Defoliation and Corn Productivity Performance

“…For stem diameter, whose average values ranged from 2.1 to 2.4 cm, no significant difference was found between treatments (Tables 2 and 3) as it was also found by Vaz et al (2016) and Gaias et al (2017). According to Sangoi et al (2012), the stem has a vital function in plant support when subjected to stresses on the leaf area, caused by pests, physiological disturbances, climate, hail and wind, being a source of carbohydrate supply to compensate the plant balance.…”

Effect of tillers on corn yield: Exploring trait plasticity potential in unpredictable environments

“…These decisions could be influenced by expected behavior of corn tillers and their ability to compensate a significant portion of yield lost with missing or damaged plants. This potential was previously identified by Sangoi et al (2012a) as a successful plant mitigation strategy to overcome defoliation in mid-to-late vegetative stages and by Carter (1995) as a compensation mechanism to recover a portion of yield lost due to late frost damage.…”

Morphoagronomic traits of BRS 610 sorghum submitted to artificial defoliation

“…This fact is probably related to stem photoassimilates, as emphasized in literature by Alvim et al (2010) and Sangoi et al (2012). For Sangoi et al (2001), hybrids that have the characteristic to redirect stem sugars to another part of the plant, have greater agronomic stability, which may have occurred in this Means followed by the same lowercase letter in line and capital letter in column are from the same group according to Scott Knott test at 5% of probability.…”