Action of auxin inhibitors on growth and grain yield of soybean

Fernando Debastiani,José Abramo Marchese,Felipe Patel,Elouize Xavier,Michelangelo Muzell Trezzi,Edemir Miotto Junior,Gederson Luiz Buzzello

doi:10.1590/s0034-737x2013000500004

Fernando Debastiani, José Abramo Marchese + Show 5 more

Open Access

https://doi.org/10.1590/s0034-737x2013000500004

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Abstract

Soybean genotypes grown in sub-tropical climate may exhibit lodging. The plant lodging is influenced by soil type and fertility level, sowing date, latitude and altitude of the location, plant population and conditions of crop development. Plant regulators and herbicides are able to avoid or reduce plant lodging. This study aimed to verify the effects of the growth regulators TIBA and daminozide on vegetative growth and yield of soybean cultivar CD 214 RR. The experiment was carried out at a field in randomized block design with four replications in a factorial scheme. The A factor was represented by the combination of regulators TIBA and daminozide and its concentrations, and the Factor B was seven times of evaluation of injury and plant height or eight times of evaluation of lodging. In the range of doses used, the application of daminozide resulted in greater injury to soybean plants than TIBA. The smaller plant height was achieved by the application of 6 g ha-1 of TIBA and 1200 g ha-¹ of daminozide. Treatments with daminozide (100 g ha-¹) and TIBA (10 g ha-1) stood out due to the reduced lodging of soybean plants. Grain weight increased linearly when the levels of TIBA increased. There was a negative correlation between lodging and grain yield and a positive correlation between plant height and lodging. There was also a negative correlation between injury caused by the application of plant regulators and lodging.

Highlights

Growth retardants are plant growth regulators that lower division and cell elongation in meristematic tissues, and physiologically regulate plant height (Cathey, 1964), without decreasing grain yield (Rademacher, 2000)
The treatments were arranged in a factorial scheme, where the first factor corresponded to plant regulators and their concentrations, as it follows: untreated control, 2,3,5-triiodobenzoic acid (TIBA commercial product) in concentrations 6, 8 and 10 g ha-1 applied at R1 stage, and daminozide (B-Nine commercial product), at doses 100, 300, 400, 1200 g ha-1, applied at stage V
Plants treated with TIBA, at all concentrations showed no injury, and no differences compared to the control treatment at any evaluation time

Summary

Introduction

Growth retardants are plant growth regulators that lower division and cell elongation in meristematic tissues, and physiologically regulate plant height (Cathey, 1964), without decreasing grain yield (Rademacher, 2000). Its use can prevent the excessive growth of soybean plants, minimizing the lodging. Plant growth regulators can cause injury or phytotoxicity to plants, so it is important that these issues do not decrease the crop yield. The 2,3,5-triiodobenzoic acid (TIBA) and succinic acid-2,2-dimethylhydrazide (daminozide) are well-known plant growth regulators. The TIBA is an inhibitor of basipetal auxin transport (Geldner et al 2001). The daminozide inhibits the action of tryptamine oxidase in the endogenous indolylacetic acid biosynthesis (Castro & Appezzato-da-Glória, 1993). According to Rademacher (2000), daminozide is an inhibitor of 2-oxoglutarate dioxygenase and blocks the formation of gibberellic acid (GA)

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