Cotton root growth response to mepiquat chloride application in early reproductive stages are cultivar dependent

Abstract

Mepiquat chloride (MC) is essential to reduce shoot growth and improve cotton (Gossypium hirsutum L. var. latifolium Hutch) harvest index, but the effect of high rates on cotton root growth is not known yet. The objective of this study was to evaluate the effect of different rates of MC application on root and shoot growth of different cotton cultivars. Two studies were conducted in a greenhouse to (a) characterize the stage of greatest susceptibility to high rates of MC and (b) evaluate the response to MC on root growth of cultivars of different maturity cycles (FM 906GLT, early; TMG 44B2RF, mid‐early; TMG 81WS, late; and FM 985GLTP, late). Regardless of the cultivar, spraying of MC in the early reproductive stage (B3) reduced root length. These reductions began approximately 2 wk after spraying. But spraying MC in the late reproductive stage (F1) can increase root length. Application of up to 30 g ha−1 of MC hindered shoot growth for 2 wk, but applications of 60 g ha−1 hindered shoot growth for 3 wk. We recommend a maximum application of 30 g ha−1 of MC in the first application to reduce root growth damage and balance biomass production.

Enhance Growth and Flower Quality of Chrysanthemum indicum L. with Application of Plant Growth Retardants

“…Mepiquat chloride is a growth regulator widely applied in different crop production; it improves the allocation of biomass to a reproductive structure and by that leaf area and node length is reduced [27,28]. Mepiquat chloride inhibits gibberellins biosynthesis, has a high potential to restrict cell elongation, and so it is reducing the growth of plants [29,30].…”