Potential of yam (Dioscorea cayenensis) and sweet potatoes (Ipomaea batatas) for in-vitro culture of the banana burrowing nematode (Radopholus similis)

Abstract

This study focused on investigating the potential of yam (Dioscorea cayenensis) and sweet potatoes (Ipomaea batatas) as alternative substrates for in-vitro culture of the banana burrowing nematode (Radopholus similis). The study aimed to address the challenges associated with the current method of culturing nematodes on carrot discs, including contamination and limited nematode production. Additionally, the research aimed to analyse the effect of temperature on the reproduction of R. similis in-vitro on different substrates. Nematodes were extracted from infected banana roots using the modified Bearman technique and the substrates were prepared into discs under the laminar airflow. The treatments (substrates) were yams, carrots and sweet potato each replicated seven times. After inoculation with sterile female nematodes, the substrates were incubated at 27°C for 5 weeks for the first objective and then incubated at three different temperatures i.e., 25°C, 27°C, 30°C for objective two for the same period of time. Based on the results, the study concluded that sweet potato more than yam could be a viable alternative to carrot discs for the in-vitro culture of R. similis. Carrots had a reproduction factor 31.01 while yams had an RF of 9.46 and finally the sweet potato had an RF of 62.2. The sweet potato offered advantages such as more numbers of R. similis, longer shelf life and reduced susceptibility to contamination. The study further emphasized the effect of temperature on nematode reproduction since the results clearly indicated that 27°C was the best temperature for in-vitro culturing R. similis as compared to 25°C and 30°C because substrates at 27°C temperature registered the highest reproduction factor. In summary, this research contributes to the development of improved methods for nematode culturing and provides insights into the potential of yam and sweet potatoes as alternative substrates. The findings have practical implications for nematode management strategies in banana production, particularly in terms of resistance breeding and screening procedures. Further research is recommended to explore the full potential of these alternative substrates and their applicability in different environmental conditions.