Initial growth of clonal seedlings of Passiflora mucronata genotypes in response to paclobutrazol concentrations

Patrick Alves De Oliveira,José Carlos Lopes,Paula Aparecida Muniz De Lima,Ariany Das Graças Teixeira,Guilherme Bravim Canal,Rodrigo Sobreira Alexandre,Gardênia Rosa De Lisbôa Jacomino

doi:10.33448/rsd-v9i12.10862

Patrick Alves De Oliveira, José Carlos Lopes + Show 5 more

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https://doi.org/10.33448/rsd-v9i12.10862

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Abstract

Paclobutrazol (PBZ) is a plant growth regulator of the triazole group that can block the biosynthesis of gibberellic acid, resulting in reduced plant height and increased stem diameter. This study aimed to evaluate the effect of different paclobutrazol concentrations on seedling quality of Passiflora mucronata Lam. Two Passiflora mucronata genotypes were used, one resistant (G5) and one tolerant (G7) to fusariosis, prepared as cuttings treated with PBZ. The experimental design was completely randomized, in a 2 x 4 factorial arrangement corresponding to two genotypes (G5 and G7) and four PBZ concentrations (0, 5, 10, and 15 mg plant-1), with three replications of four plants. Data were subjected to analysis of variance, regression analysis, and the F-test, followed by Pearson’s correlation test between variables. PBZ promoted an increase in the plagiotropic shoot diameter and the leaf area index of genotypes G5 and G7, in addition to increased shoot length in genotype G5 and increased number of leaves in genotype G7. PBZ also resulted in increased photosynthesis and stomatal conductance. There was a positive correlation for genotype G5, between the plagiotropic shoot diameter and the leaf transpiration rate, and for genotype G7, between the plagiotropic shoot diameter and the number of leaves. Genotypes G5 and G7 showed different phenotypic responses when subjected to PBZ doses, highlighting the intraspecific divergence of the species.

Highlights

Brazil stands out as the leading passion fruit producer and consumer in the world (Passiflora spp.), with a production of 593,429 tons obtained in 41,584 hectares (Ibge, 2019), mainly cultivated by smallholder farmers in small and medium-sized properties (Furlaneto et al, 2014; Santos et al, 2016)
In a study conducted with mini-grafting, which consists of grafting apical segments from adult plants on young rootstocks, P. edulis f. flavicarpa was grafted on P. mucronata rootstocks, with an 80% success rate (Alexandre et al, 2013)
The cuttings were treated with an aqueous solution in their basal portion for 10 seconds, with the application of 1,000 mg L-1 of indolebutyric acid (IBA) (Alexandre et al, 2014), and planted in 50 cm3 polyethylene tubes filled with the Bioplant® substrate, being kept in a plant nursery provided with a mist irrigation system

Summary

Introduction

Brazil stands out as the leading passion fruit producer and consumer in the world (Passiflora spp.), with a production of 593,429 tons obtained in 41,584 hectares (Ibge, 2019), mainly cultivated by smallholder farmers in small and medium-sized properties (Furlaneto et al, 2014; Santos et al, 2016). Passiflora mucronata Lam., found in the coastal restinga vegetation of the states of Espírito Santo and Rio de Janeiro (Magnago et al, 2011; Garbin et al, 2012), is a species of high agronomic interest for investigations due to its resistance to diseases such as bacterial leaf blight, fruit and branch anthracnose, and microorganisms such as Fusarium (Correia, 2019) In this context, the species becomes a viable alternative as a control method for resistance detection and studies on graft compatibility with commercial species for use as rootstocks (Alexandre et al, 2013; Oliari et al, 2016; Schmildt et al, 2018). The mini-grafting of P. edulis on P. mucronata resulted in an 89% success rate (Oliari et al, 2016)

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