Influence of gibberellin inhibitors applied during flowering of nonirrigated 'Hass' avocado trees

Bruna Do Amaral Brogio,Sérgio Figueiredo Angolini,Rafael Vasconcelos Ribeiro,Tatiana Cantuarias-Avilés,Edypol Guilherme Baptista,Simone Rodrigues Da Silva

doi:10.1590/s0100-204x2018000800006

Bruna Do Amaral Brogio, Sérgio Figueiredo Angolini + Show 4 more

Open Access

https://doi.org/10.1590/s0100-204x2018000800006

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Abstract

Abstract: The objective of this work was to evaluate the effect of different gibberellin biosynthesis inhibitors on shoot growth above the panicle, as well as on fruit yield, size, and shape of nonirrigated 'Hass' avocado (Persea americana) trees. The experiment was carried out in a randomized complete block design, with five treatments, four replicates, and 40 trees. From 2013 to 2015, the following treatments were applied at full bloom, as foliar sprayings: water (control), 250 mg L-1 prohexadione-calcium, 2,500 mg L-1 trinexapac-ethyl, 1,750 mg L-1 paclobutrazol, and 350 mg L-1 uniconazole; the first two are acylcyclohexanediones and the last two, triazoles. Fruit yield, yield efficiency, and alternate bearing were not affected by the application of plant growth regulators. However, the gibberellin inhibitors increased fruit size and modified the fruit shape of nonirrigated 'Hass' avocado. Uniconazole reduces shoot growth above the panicle, and this effect may vary depending on environmental conditions, especially water supply.

Highlights

Brazil has excellent soil and climate conditions for avocado (Persea americana Mill., Lauraceae) production
Gibberellin inhibitors applied during flowering of nonirrigated 'Hass' avocado trees orchards of 'Hass' avocado, the main cultivar planted around the world, have shown the effectiveness of applying phytoregulators in the bloom period, with improvements in fruit yield and size, increasing the economic return to growers (Erasmus & Brooks, 1998; Lovatt, 2005)
The objective of this work was to evaluate the effect of different gibberellin biosynthesis inhibitors on shoot growth above the panicle, as well as on fruit yield, size, and shape of nonirrigated 'Hass' avocado trees

Summary

Introduction

Brazil has excellent soil and climate conditions for avocado (Persea americana Mill., Lauraceae) production. In order to manage these limitations and increase fruit yield, the application of phytoregulators has been adopted in the main avocado producing countries (Lovatt, 2005). Gibberellin inhibitors applied during flowering of nonirrigated 'Hass' avocado trees orchards of 'Hass' avocado, the main cultivar planted around the world, have shown the effectiveness of applying phytoregulators in the bloom period, with improvements in fruit yield and size, increasing the economic return to growers (Erasmus & Brooks, 1998; Lovatt, 2005). Symons & Wolstenholme (1990) pointed out that the intense competition for resources between the shoot growing above the panicle and the concurrently developing flowers and newly set fruit is mitigated by the application of gibberellin inhibitors The most widely adopted phytoregulators in irrigated avocado orchards are gibberellin biosynthesis inhibitors, the triazoles paclobutrazol and uniconazole (Menzel & Le Lagadec, 2014). Symons & Wolstenholme (1990) pointed out that the intense competition for resources between the shoot growing above the panicle and the concurrently developing flowers and newly set fruit is mitigated by the application of gibberellin inhibitors

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