A comparative study of the reproductive fitness and pathogenicity of a population of Radopholus similis from Davao, Philippines, on banana (Musa spp.)

Abstract

The in vitro reproductive fitness on carrot discs and the in vivo pathogenicity on selected FHIA (Fundación Hondureña de Investigaciónes Agrícola) banana hybrids of a population of Radopholus similis isolated from banana in Davao, Philippines, were investigated at the Bureau of Plant Industry, Davao City, Philippines. It was shown that on carrot discs following inoculation with 25 females, the Davao population had the highest population density and multiplication rate compared with two other R. similis populations from the Philippines (Los Baños and Quezon) and two exotic populations of R. similis (from Uganda and Indonesia). According to the Gompertz model, the Davao population also had a short lag phase and a high maximum specific growth. Following inoculation with one single female, the Davao population also had the highest multiplication rate and the highest proportion of juveniles and females compared with the other four populations included in the experiments. Nine weeks after inoculation with 1000 vermiforms, the R. similis population from Davao had reduced the plant height of the FHIA hybrids included in the experiment (FHIA-3, FHIA-4, FHIA-5, FHIA-18 and FHIA-23) on average by 37%, plant girth by 5.3–40.9%, shoot weight by 20.1–65.8% and root weight by 31.7–69.7%, indicating the high pathogenicity of this population on banana. FHIA-4 was tolerant to R. similis infection.

Keywords:

• burrowing nematode
• carrot discs
• damage
• FHIA banana hybrids
• pot experiments
• reproduction

Acknowledgements

This study was funded by VL.I.R. (Flemish Interuniversity Council, Belgium) and the financial support for the first author is gratefully acknowledged. We also thank the staff of the Plant Disease Laboratory at the Bureau of Plant Industry, Bago-Oshiro, Davao City, Philippines, and the co-researchers of the VL.I.R. funded Nematology project at the Institute for Plant Breeding, University of the Phillipines, Los Baños, Laguna, Philippines, for their collaboration.