Crescimento e rendimento do algodoeiro BRS-200 com aplicações de cloreto de mepiquat e lâminas de irrigação

Abstract

RESUMOVisando contribuir para a melhoria do nível tecnológico da cotonicultura regional, conduziu-se um experimento na estação experimental da EMBRAPA Algodão, em Barbalha, CE, no período de agosto a novembro de 2003, com o objetivo de se estudar o crescimento e o rendimento do algodoeiro BRS 200 Marrom, submetido a quatro doses do regulador de crescimento cloreto de mepiquat (0, 50, 75 e 100 g i.a. ha -1 ) e cinco lâminas de irrigação (125,30, 298,35, 353,89, 521,86 e 741,64 mm); o delineamento estatístico foi em blocos ao acaso, com 4 repetições e arranjo fatorial 4 x 5. A aplicação de 741,64 mm resultou em aumento de 339% na produtividade do algodoeiro. Não se constatou efeito interativo entre lâminas de irrigação e doses de cloreto de mepiquat mas este, no nível de 100 g i.a. ha -1 , reduziu as variáveis de crescimento sem, no entanto, afetar o rendimento nem a abertura do primeiro capulho do algodoeiro. (125.30, 298.35, 353.89, 521.86 and 741.64 mm), in randomized block design, with 4 replications. The irrigation with 741.64 mm resulted in a 339% increase in cotton yield. There was no interactive effect between irrigation levels and mepiquat chloride factors, but the growth regulator, at 100 g i.a. ha -1 , reduced the growth variables without affecting the yield or the first cotton boll opening.

Physiology and production of naturally-colored cotton under irrigation strategies using salinized water

“…The results obtained in the present study revealed that the effects of salinity on naturally-colored cotton production are related to stress during the flowering and production stages. Production decreases due to ECw increases may be attributed to lower water absorption by plants under salt stress because of the lower soil water potential, as concluded by Cordão Sobrinho et al (2007). This was confirmed by the results of the present study, in which the effects of salinity were greater on gas exchange than on a chlorophyll fluorescence, i.e., water restriction due to increased water salinity caused reductions in stomatal conductance, transpiration, and liquid photosynthesis, but did not cause irreversible damage to the photosynthetic apparatus, since the quantum yield values for photosystem II were over 0.75, showing that ionic effects were less expressive.…”

Cultivar, Plant Height and Fungicide for Integrated Control of Ramularia Spot and Increased Cotton Yield

“…It is hypothesized that because of the shortening of the internodes, the distance between the youngest and oldest leaves of the plants was reduced, favoring the dispersion of the pathogenic conidia produced in the lower part of the plants. In addition, it may be that plants with lower height provided greater light penetration within the canopy because they had fewer leaves than larger plants (Sobrinho et al, 2007). As a result, there could have been a higher average daily temperature in the older leaves, and consequently, a more favorable environment for the occurrence of leaf spot (Rathaiah, 1977).…”

“…for the cultivars FMT 701 and FM 975 and 100 g. of i.a. for the cultivar FM 944 (Cordã o Sobrinho et al, 2007). Fungicide and growth regulator sprays were applied with a constant pressure CO 2 sprayer with a 3 m boom and six spray tips (XR 11002) spaced 0.50 m apart.…”

Potassium fertilization in the cultivation of colored cotton irrigated with saline water

“…The reduction in cotton seed weight due to the increase in ECw can be attributed to the reduction in the osmotic potential and metabolic disorders, especially related to the absorption of water and nutrients by plants, resulting in lower number of bolls and, consequently, reductions in cotton production (Cordão Sobrinho et al, 2007;Oliveira et al, 2012). Santos et al (2016), working with the cotton cv.…”