Genetic Uniformity of the MSXJ papaya hybrid (Carica papaya L.) during Micropropagation

Abstract

Objective. To analyze the genetic uniformity of the MSXJ papaya hybrid vitroplants, obtained via direct organogenesis.


Design/methodology/approach. The MSXJ papaya hybrid presents quality characteristics for national and export markets. The in vitro plant tissue culture represents a tool for its multiplication and conservation, but somaclonal variation can decrease its genetic and agronomic uniformity. In order to analyze the genetic uniformity of this hybrid vitroplants, 10 ISSR primers were used in micropropagated vitroplants during nine subcultures. DNA extraction was carried out with the CTAB method. The data analysis was performed with the PopGene v 1.3.1 program.


Results. Eighty five loci of 200 to 2000 bp were generated, with 37 polymorphic loci. In the cluster analysis, three groups were observed that separated subculture one, subcultures two through eight, and subculture nine; the Gst value of 0.87 indicated genetic uniformity up to subculture eight.


Limitations/implications. Papaya is one of the most important tropical fruits worldwide; however it is necessary to have healthy and genetically uniform plants that guarantee their quality. In vitro propagation allows to produce healthy and uniform plants, but it is necessary to study their genetic uniformity during their micropropagation.


Findings/conclusions. The in vitro multiplication of the MSXJ papaya hybrid allowed to regenerate vigorous plants in 30 days. Molecular profiles indicated that up to subculture eight plantlets were genetically uniform, so it is recommended not to carry out more than eight subcultures during micropropagation.