Author(s)

Andréa Celina Ferreira Demartelaere, Luciana Cordeiro do Nascimento, Cristina O. Marinho, Marciano Costa Nunes, Patrícia Clemente Abraão, Rommel S. S. Gomes, Mônica Danielly de Mello Oliveira, Larissa Almeida, Mirelly M. Porcino, Caroline Vargas e Silva, Wilza C. O. Souza

Programa de Pós-Graduacao em Agronomia, Departamento de Fitotecnia e Ciências Ambientais, Universidade Federal da Paraíba, Areia, Brazil.

The tangerine pathotype of Alternaria alternata is the aetiological agent of Alternaria brown spot on tangerines. In the state of Paraíba, Brazil, its occurrence on “Dancy” tangerine trees is associated with genetic aspects as well as the influence of environmental conditions on reproduction and dissemination within and between populations. The aim of the present study was to evaluate the diversity of isolates of this pathogen using morphophysiological and molecular markers. For the analysis of mycelial growth and sporulation, 30 isolates from different locations were examined at 24-hour intervals until the seventh day, when the spores were quantified. The 30 isolates were characterised based on molecular markers (ISSR) and genetic similarity (Jaccard index). A factor arrangement was used: 30 isolates, four media (ODA, PDA, LEA and V8), three light regimes (continuous dark, alternating light and continuous light) and three temperatures (15°C, 25°C and 35°C), with 12 repetitions. Groups 1, 2 and 3 presented low genetic variability. Group 4 showed high genetic variability of the isolates obtained from the Massaranduba (state of Paraíba-Brazil) producing region and higher mycelial growth and sporulation of A. alternata. The continuous light regime and the temperature 25°C in PDA and V8 media were the ideal conditions for the mycelial growth and sporulation, respectively, of the isolates of A. alternata.

Citrus tangerine, Alternaria Brown Spot, Fungal Variability, Environment Factors, ISSR Markers

Ferreira Demartelaere, A. , do Nascimento, L. , Marinho, C. , Nunes, M. , Abraão, P. , Gomes, R. , de Mello Oliveira, M. , Almeida, L. , Porcino, M. , e Silva, C. and Souza, W. (2018) Diversity among Isolates of the Tangerine Pathotype of Alternaria alternata. American Journal of Plant Sciences, 9, 196-215. doi: 10.4236/ajps.2018.92017.