Resource use efficiency of cotton in improved vs conventional planting geometry with exogenous application of bio-stimulant and synthetic growth retardant.

M Arif,S Latif,A Anwar,M N Salim,N Hussain,S Naz,A Yasmeen,I Qadir,J Iqbal,M Bibi

doi:10.1590/1519-6984.213951

Abstract

Plant growth regulators and improved planting density are the innovative techniques in the establishment of more productive cotton crop. A field study was planned to assess the role of growth regulators in the resource utilization efficiency of cotton cultivars under different row spacing at Agronomic Research Area, Bahauddin Zakariya University Multan and Usmania Agricultural Farm, Shujaabad during Kharif 2012. The study was comprised of cotton cultivars viz. CIM-573 and CIM-598, cultivated under conventional (75 cm), medium (50 cm) and improved ultra-narrow row spacing (25 cm) and foliar spray of growth regulators viz. moringa leaf extract (MLE) and mepiquat chloride (MC), either alone or in combination, distilled water as a control. The application of MLE alone and in combination (MLE + MC) showed the promoting effect on crop growth rate, net assimilation rate, leaf area index, leaf area duration, sympodial branches and number of bolls leading to higher seed cotton yield of both cotton cultivars grown under conventional row spacing. While application of MC averts the plant growth without considerably improving the productivity. MLE being rich source of growth promoting hormone and nutrients showed its potential to a far greater extent under conventional row spacing in efficient utilization of available resources compared to MC and distilled water.

Highlights

The management of available resources i.e. land, water, seed, optimum growing season and labour to enhance their utilization is one of the key factors in crop management practice
The application of moringa leaf extract (MLE) alone and in combination (MLE + mepiquat chloride (MC)) showed the promoting effect on crop growth rate, net assimilation rate, leaf area index, leaf area duration, sympodial branches and number of bolls leading to higher seed cotton yield of both cotton cultivars grown under conventional row spacing
MLE being rich source of growth promoting hormone and nutrients showed its potential to a far greater extent under conventional row spacing in efficient utilization of available resources compared to MC and distilled water

Summary

Introduction

The management of available resources i.e. land, water, seed, optimum growing season and labour to enhance their utilization is one of the key factors in crop management practice. Higher cotton plant population had earlier canopy development, and self-shading hinders the solar radiation prevalence on lower leaves resulting in the reduction of photosynthesis and assimilate production, which resulting in loss of seed cotton yield and fiber quality (Brodrick et al, 2013). Application of plant growth retardants is one of the approaches normally used in cotton production for modifying morphological and reproductive growth which helps in enhancing the cotton productivity by reducing the auto‐shading (Gonias et al, 2012). Use of MC improved the photosynthesis mechanism and canopy CO2 exchange rate, in relation with a greater specific leaf weight considering that additional amount of carbohydrates stored in the leaves (Zhao and Oosterhuis, 2000). Cotton plants produced thicker leaves having excessive chlorophyll that influence the photosynthetic potential and productivity (Fan et al, 2013)

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