Comparative Productivity and Seed Nutrition of Cotton by Plant Growth Regulation under Deficient and Adequate Boron Conditions

PLANTA DANINHA ZOHAIB, A. et al. Comparative productivity and seed nutrition of cotton by plant growth regulation under deficient and ... 151103-PD-2016 (9 páginas) PROVA GRÁFICA SOCIEDADE BRASILEIRA DA CIÊNCIA DAS PLANTAS DANINHAS <http://www.sbcpd.org> Article ZOHAIB, A.1* JABBAR, A.1 AHMAD, R.1 BASRA, S.M.A.1 1 ISSN 0100-8358 (print) 1806-9681 (online) COMPARATIVE PRODUCTIVITY AND SEED NUTRITION OF COTTON BY PLANT GROWTH REGULATION UNDER DEFICIENT AND ADEQUATE BORON CONDITIONS Produtividade Comparativa e Nutrição de Sementes de Algodão com o Uso de Regulador de Crescimento Vegetal sob Condições Adequadas e na Deficiência de Boro ABSTRACT - Plant growth regulators (PGRs) potentially improve the productivity and nutritional quality of crops through modulation of morphology, physiology and nutrient dynamics within plants. However, the effect of PGRs may differ under environments with deficient and adequate nutrients. Here the role of mepiquat chloride (MC) on the yield and seed nutritional quality of cotton was explored under boron (B) deficiency and adequate conditions in a two-year field study. Mepiquat chloride was foliar-applied at different dosages (0 and 70 mg L-1) and growth stages (squaring and flowering) and B was applied into soil (0, 1, 1.5, 2 and 2.5 kg ha-1) to establish B deficiency and adequate levels. Seed cotton yield and seed nutritional quality were substantially higher under adequate B conditions, compared to B deficiency. Nonetheless, MC applications improved the seed cotton yield, seed oil yield, seed protein yield and concentration of seed mineral nutrients (N, P, K, B, Zn and Fe except for Mn) under both B deficiency and adequate conditions. Nonetheless, the improvement in all traits caused by MC application was greater under adequate B conditions (2-2.5 kg ha-1 B), compared to B deficiency conditions. Furthermore, the application of MC at squaring proved more beneficial in improving the seed cotton yield and nutritional quality, compared to the flowering stage. In conclusion, MC application improves seed cotton yield and cotton seed nutritional quality under both deficient and adequate B conditions, through an improved nutrient accumulation in seed tissues; however, the efficacy of MC is affected by B deficiency. * Corresponding author: <> Received: May 11, 2017 Approved: May 17, 2017 Planta Daninha 2018; v36:e018177790 Copyright: This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided that the original author and source are credited. 1 Keywords: Boron deficiency; Mepiquat chloride; Seed cotton yield; Cotton seed nutritional quality; Nutrient Dynamics RESUMO - Os reguladores de crescimento vegetal (RCV) melhoram potencialmente a produtividade e a qualidade nutricional das culturas através da modulação da morfologia, fisiologia e dinâmica dos nutrientes nas plantas. No entanto, o efeito dos RCV pode diferir sob ambientes com deficiência ou conteúdos adequados de nutrientes. O papel do cloreto de mepiquat (CM) na produtividade e na qualidade nutricional da semente de algodão foi explorado sob deficiência ou condições adequadas de boro em um estudo de campo de dois anos. O cloreto de mepiquat foi aplicado nas folhas em diferentes doses (0 e 70 mg L-1) e estádios de crescimento (formação de botões florais e abertura das flores), e o B foi aplicado no solo (0, 1, 1,5, 2 e 2,5 kg ha-1) para estabelecer deficiência e níveis adequados desse nutriente. O rendimento do algodão e a qualidade nutricional das sementes foram substancialmente maiores em condições de B adequadas, comparadas à deficiência Department of Agronomy, University of Agriculture, Faisalabad 38040, Pakistan. Doi: 10.1590/S0100-83582018360100040 Planta Daninha 2018; v36:e018177790 ZOHAIB, A. et al. Comparative productivity and seed nutrition of cotton by plant growth regulation under deficient and ... 2 de B. No entanto, as aplicações de CM melhoraram o rendimento do algodão, o rendimento de óleo de sementes, o rendimento de proteína de sementes e a concentração de nutrientes minerais de sementes (N, P, K, B, Zn e Fe, exceto Mn) sob deficiência e condições adequadas de B. Entretanto, a melhoria em todas as características causada pela aplicação de CM foi maior em condições de B adequadas (2-2,5 kg ha-1 de B), quando comparadas às condições de deficiência. Além disso, a aplicação de CM durante a formação dos botões mostrou-se mais benéfica na melhoria do rendimento do algodão e da qualidade nutricional, em comparação com o estádio de abertura das flores. Em conclusão, a aplicação de CM melhora o rendimento do algodão e a qualidade nutricional das suas sementes em condições de deficiência e condições adequadas de B, por meio de melhor acumulação de nutrientes nos tecidos das sementes; contudo, a eficácia do CM é afetada pela deficiência de B. Palavras-chave: deficiência de boro, cloreto de mepiquat, rendimento do algodão, qualidade nutricional de sementes de algodão, dinâmica dos nutrientes. INTRODUCTION Cotton (Gossypium hirsutum L.) is cultivated worldwide for fibers and cottonseeds, due to a diverse seed composition, i.e. oil, fatty acids, protein and mineral nutrition (Bellaloui et al., 2015). Its oil is used for human consumption and meal for animal feed. The production of cottonseed oil has reached the third position after rapeseed and soybean (USDA-ERS, 2013). Cottonseeds are rich in protein (17-27%), oil (12-30%), saturated fatty acids (∼29%) and unsaturated fatty acids (∼70%) (Dowd et al., 2010; Pettigrew and Dowd, 2011). Various environmental and management practices influence the cottonseed composition despite genetic control (Pettigrew and Dowd, 2011; Bellaloui et al., 2015). Thus, a better management of crops and environmental factors is essential to maintain and ensure high productivity and nutritional quality of cottonseeds. Boron is an essential micronutrient that directly or indirectly influences plant growth and development, and physiological and biochemical processes. It is mainly involved in the metabolism of nucleic acid, sugar and starch, protein, indole acetic acid and phenol, cell wall biosynthesis, and it regulates membrane integrity and functioning (Goldbach et al., 2001; Barker and Pilbeam, 2007). Boron deficiency is spreading throughout the world, with wide areas in some regions of the world and smaller areas in others (Shorrocks, 1997; Niaz et al., 2002). Several factors have been held responsible for B deficiency in soil, including drought, high soil pH, calcareousness, low organic matter in soil, B leaching and fixation with clay minerals, and microbial activity (Shorrocks, 1997; Mengel and Kirkby, 2001; Barker and Pilbeam, 2007). Boron deficiency is associated with the abnormal growth of apical regions, normally due to the disturbance in cell wall growth and cell division. However, the most prominent effects (...truncated)