ISSN e:2007-4034 / ISSN print: 2007-4034

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     Vol. 27, issue 1 January - April 2021   Creative Commons License

      
 

     Vol. 27, issue 1 January - April 2021  

 
  

Effect of population densities and paclobutrazol applications on seedling quality and yield in tomato

Efecto de densidades de población y aplicaciones de paclobutrazol en calidad de plántula y rendimiento en jitomate

Esaú del Carmen Moreno-Pérez; Felipe Sánchez-Del Castillo; Mario Ruiz-Díaz; Efraín Contreras-Magaña

Keywords: Solanum lycopersicum, late transplanting, growth retardants, greenhouse production

10.5154/r.rchsh.2020.05.010

Received: 2020/05/19
Accepted: 2020-10-03
Available online: 2020-11-17
Pages:5-17

The development of an alternative greenhouse tomato (Solanum lycopersicum L.) production system to obtain four annual growing cycles requires delaying transplantation from 50 to 60 days after sowing (das). The study objectives were to evaluate the effects of paclobutrazol applications and population densities in the seedbed on the quality of seedlings to be transplanted at 60 das, and on the number of flowers and yield of plants pruned to three clusters. A randomized complete block experimental design was used with a split-plot arrangement with four replicates and 16 treatments that resulted from combining two population densities (150 and 300 seedlings∙m-2) and seven paclobutrazol treatments (one, two and three applications with 25 and 50mg∙L-1 of active ingredient), plus two controls (without application). The lower density in the seedbed resulted in lower height, larger stem diameter and higher seedling dry weight at 60 das; however, at the end of the growing cycle the number of flowers and the yield per plant were lower. Triple applications of paclobutrazol, with 25 and 50 mg∙L-1, significantly decreased height and leaf area, but dry weight and stem thickness were similar to the control. Triple application of paclobutrazol resulted in two flowers and two more fruits per plant compared to the control, possibly because the temporary arrest of vegetative growth, caused by paclobutrazol, left more photoassimilates available for the inflorescences in formation.

The development of an alternative greenhouse tomato (Solanum lycopersicum L.) production system to obtain four annual growing cycles requires delaying transplantation from 50 to 60 days after sowing (das). The study objectives were to evaluate the effects of paclobutrazol applications and population densities in the seedbed on the quality of seedlings to be transplanted at 60 das, and on the number of flowers and yield of plants pruned to three clusters. A randomized complete block experimental design was used with a split-plot arrangement with four replicates and 16 treatments that resulted from combining two population densities (150 and 300 seedlings∙m-2) and seven paclobutrazol treatments (one, two and three applications with 25 and 50mg∙L-1 of active ingredient), plus two controls (without application). The lower density in the seedbed resulted in lower height, larger stem diameter and higher seedling dry weight at 60 das; however, at the end of the growing cycle the number of flowers and the yield per plant were lower. Triple applications of paclobutrazol, with 25 and 50 mg∙L-1, significantly decreased height and leaf area, but dry weight and stem thickness were similar to the control. Triple application of paclobutrazol resulted in two flowers and two more fruits per plant compared to the control, possibly because the temporary arrest of vegetative growth, caused by paclobutrazol, left more photoassimilates available for the inflorescences in formation.

 

Comparative analysis of floral volatiles between the ‘Hass’ variety and Antillean race avocado

Análisis comparativo de los volátiles florales entre la variedad de aguacate ‘Hass’ y la raza Antillana

Álvaro J. Campuzano-Granados; Leopoldo Cruz-López

Keywords: Persea americana, taxonomy, solid-phase microextraction, gas chromatography-mass spectrometry, terpenes

10.5154/r.rchsh.2020.05.012

Received: 2020/05/26
Accepted: 2020/10/03
Available online: 2020-11-17
Pages:19-26

Mexico is the world's leading producer of ‘Hass’ avocado and the Antillean race avocado is grown in the south of the country. Avocado plant flowers produce a great variety of volatile compounds, which act as chemical signals to attract herbivores and pollinating insects, in addition to providing information for taxonomic purposes. The research aim was to identify and compare the floral volatiles between the ‘Hass’ and Antillean race avocado. Floral volatiles were captured by solid-phase microextraction, and identification was made by gas chromatography coupled to mass spectrometry (GC-MS). Thirty-five compounds were identified as constituents of the flower aromas; most were monoterpenes and sesquiterpenes. α-Pinene, sabinene, β-pinene, (E)-linalool oxide, benzyl nitrile, lavandulol, methyl salicylate, α-copaene, β-gurjunene and γ-muurolene were only found in ‘Hass’ avocado flowers. The differences can help classify the two types of avocados analyzed into different races. Eventually, this information could be used to find out if these volatile compounds influence the interactions of avocado with its pollinating insects and herbivores.

Mexico is the world's leading producer of ‘Hass’ avocado and the Antillean race avocado is grown in the south of the country. Avocado plant flowers produce a great variety of volatile compounds, which act as chemical signals to attract herbivores and pollinating insects, in addition to providing information for taxonomic purposes. The research aim was to identify and compare the floral volatiles between the ‘Hass’ and Antillean race avocado. Floral volatiles were captured by solid-phase microextraction, and identification was made by gas chromatography coupled to mass spectrometry (GC-MS). Thirty-five compounds were identified as constituents of the flower aromas; most were monoterpenes and sesquiterpenes. α-Pinene, sabinene, β-pinene, (E)-linalool oxide, benzyl nitrile, lavandulol, methyl salicylate, α-copaene, β-gurjunene and γ-muurolene were only found in ‘Hass’ avocado flowers. The differences can help classify the two types of avocados analyzed into different races. Eventually, this information could be used to find out if these volatile compounds influence the interactions of avocado with its pollinating insects and herbivores.

 

Organic fertilization for the beginning of sweet potato (Ipomoea batatas L.) cultivation in savanna soils

Fertilización orgánica para introducir el cultivo de camote (Ipomoea batatas L.) en suelos de la sabana

Elton da Silva Dias; João Luiz Lopes Monteiro Neto; Brito Luís Dresch; Rannyonara Oliveira Rodrigues; Wellington Farias Araújo; Edvan Alves Chagas; Sonicley da Silva Maia; Raphael Henrique da Silva Siqueira; Pollyana Cardoso Chagas; Roberto Tadashi Sakazaki; Edgley Soares-da-Silva; José de Anchieta Alves de Albuquerque; Carlos Abanto-Rodríguez

Keywords: nutrient management, savanna soil, organic material

10.5154/r.rchsh.2020.05.011

Received: 2020-05-25
Accepted: 2020-10-14
Available online: 2021-01-13
Pages:27-42

Due to limited information on sweet potato (Ipomoea batatas L.) cultivation in uncultivated savanna areas, the objective of this research was to determine the ideal dose and type of organic fertilizer for sweet potato cultivation in savanna soils with no history of use. In four experiments, the following fertilizer doses were tested: cattle manure (0, 10, 20, 30, and 40 t∙ha-1), poultry manure (0, 5, 10, 15, and 20 t∙ha-1), compost A (0, 0.75, 1.5, 2.25, and 3.0 t∙ha-1), and compost B (0, 0.75, 1.5, 2.25, and 3.0 t∙ha-1). The fifth experiment consisted of an organic fertilizer efficiency test using applications already recommended for sweet potato crops, which resulted in six treatments: control (without organic fertilization), cattle manure (20 t∙ha-1), poultry manure (10 t∙ha-1), compost A (1.5 t∙ha-1), compost B (1.5 t∙ha-1), and compost C (0.375 t∙ha-1). In the first four experiments, the products and their recommended doses were defined in order of production efficiency, as follows: poultry manure (doses between 13 and 20 t∙ha-1) > cattle manure (doses between 30 and 40 t∙ha-1) > compost B (doses between 0.75 and 2.25 t∙ha-1) = compost A (doses between 2.25 and 3.00 t∙ha-1). The fifth experiment concluded that: 1) poultry manure was the most suitable starting point for sweet potato cultivation in savanna soils and 2) sweet potato yield was directly linked to the commercial root mass, number of commercial roots, and branch productivity, which, in turn, were maximized by an increase in organic matter and satisfactory amounts of phosphorus in the soil.

Due to limited information on sweet potato (Ipomoea batatas L.) cultivation in uncultivated savanna areas, the objective of this research was to determine the ideal dose and type of organic fertilizer for sweet potato cultivation in savanna soils with no history of use. In four experiments, the following fertilizer doses were tested: cattle manure (0, 10, 20, 30, and 40 t∙ha-1), poultry manure (0, 5, 10, 15, and 20 t∙ha-1), compost A (0, 0.75, 1.5, 2.25, and 3.0 t∙ha-1), and compost B (0, 0.75, 1.5, 2.25, and 3.0 t∙ha-1). The fifth experiment consisted of an organic fertilizer efficiency test using applications already recommended for sweet potato crops, which resulted in six treatments: control (without organic fertilization), cattle manure (20 t∙ha-1), poultry manure (10 t∙ha-1), compost A (1.5 t∙ha-1), compost B (1.5 t∙ha-1), and compost C (0.375 t∙ha-1). In the first four experiments, the products and their recommended doses were defined in order of production efficiency, as follows: poultry manure (doses between 13 and 20 t∙ha-1) > cattle manure (doses between 30 and 40 t∙ha-1) > compost B (doses between 0.75 and 2.25 t∙ha-1) = compost A (doses between 2.25 and 3.00 t∙ha-1). The fifth experiment concluded that: 1) poultry manure was the most suitable starting point for sweet potato cultivation in savanna soils and 2) sweet potato yield was directly linked to the commercial root mass, number of commercial roots, and branch productivity, which, in turn, were maximized by an increase in organic matter and satisfactory amounts of phosphorus in the soil.

 

Endosymbionts associated with Diaphorina citri, vector of Candidatus Liberibacter asiaticus

Endosimbiontes asociados a Diaphorina citri, vector de Candidatus Liberibacter asiaticus

Mireya Paloma López-San Juan; Laura Delia Ortega-Arenas; José Abel López-Buenfil; José Manuel Cambron-Crisantos; Marco Antonio Magallanes-Tapia; Cristian Nava-Díaz

Keywords: symbiotic relationship, prokaryotes, Candidatus Wolbachia, transmission

10.5154/r.rchsh.2019.12.022

Received: 2019-12-02
Accepted: 2020-10-10
Available online: 2021-01-13
Pages:43-54

Diaphorina citri is considered the most dangerous citrus pest because it transmits Candidatus Liberibacter asiaticus, the causal agent of Huanglongbing (HLB). Like other hemiptera insects, D. citri has developed mutualistic interactions with prokaryotic organisms known as endosymbionts. This symbiosis can be obligatory, when the interaction occurs with a primary endosymbiont, or facultative, when it is a secondary endosymbiont. Symbiosis is essential for various physiological functions, but some endosymbionts can adversely affect the psyllid's abilities. D. citri is associated with a great diversity of endosymbionts, with Candidatus Carsonella ruddii, Candidatus Profftella armatura, Candidatus Wolbachia spp. and Candidatus Liberibacter spp standing out. The aim o symbiotic relationship, prokaryotes, Candidatus Wolbachia, transmission of Candidatus Liberibacter asiaticus.

Diaphorina citri is considered the most dangerous citrus pest because it transmits Candidatus Liberibacter asiaticus, the causal agent of Huanglongbing (HLB). Like other hemiptera insects, D. citri has developed mutualistic interactions with prokaryotic organisms known as endosymbionts. This symbiosis can be obligatory, when the interaction occurs with a primary endosymbiont, or facultative, when it is a secondary endosymbiont. Symbiosis is essential for various physiological functions, but some endosymbionts can adversely affect the psyllid's abilities. D. citri is associated with a great diversity of endosymbionts, with Candidatus Carsonella ruddii, Candidatus Profftella armatura, Candidatus Wolbachia spp. and Candidatus Liberibacter spp standing out. The aim o symbiotic relationship, prokaryotes, Candidatus Wolbachia, transmission of Candidatus Liberibacter asiaticus.