Abstract
Abstract The diversity and seasonal fluctuations of plant-parasitic nematodes (tylenchids) were investigated in five alfalfa fields in five counties of the Kerman Province of Iran during four consecutive seasons in 2013. Hundred soil samples were obtained per county, with 25 sub-samples per field being composited to five to represent five replicates per field per county per season. In total, 500 samples were analyzed during the study. Nematodes were extracted from soil samples using the modified tray method. In total, 11 plant-parasitic nematode genera and 12 species were recorded. According to prominence values, Ditylenchus (e.g. D. acutus, D. myceliophagus, D. terricolus and D. sarvarae), followed by Helicotylenchus pseudorobustsus, Pratylenchus neglectus and Meloidogyne javanica were the most prominent species. The season and the localities significantly affect the population densities of nematodes. Values for both the Shannon (H’) and Evenness (E) indices were the highest in Bam and the lowest in Jiroft counties. A significant, negative correlation existed between soil pH and mean population densities of Scutylenchus rugosus, while significant and positive correlations existed between soil electrical conductivity and Helicotylenchus pseudorobustus, Aphelenchoides sp., Amplimerlinius globigerus and Pratylenchus neglectus. In conclusion, diversity of plant-parasitic nematodes in Bam county was higher than other localities.
Highlights
Worldwide, alfalfa (Medicago sativa L.), a flowering plant belonging to the family Fabaceae, is cultivated as a forage crop (Tucak et al, 2008)
Plant-parasitic nematode genera (Table 1 or Fig. 2A-K) and species were identified from 25 fields sampled from five counties
According to prominence value (PV), alfalfa fields in Bardsir were dominated by H. pseudorobustsu during the Winter (Table 3; Fig. 2B) and by P. neglectus during Summer (Table 3; Fig. 2C), whereas M. brevidens dominated in fields at Rabor during winter (Table 3; Fig. 2E)
Summary
Alfalfa (Medicago sativa L.), a flowering plant belonging to the family Fabaceae, is cultivated as a forage crop (Tucak et al, 2008). A wide range of plant-parasitic nematodes have been associated with alfalfa crops in various countries, such as the USA (Gray and Griffin, 1994), South Africa (Kleynhans et al, 1996) and others (Abivardi and Sharafeh, 1973; Sturhan and Brzeski, 1991) Nematodes such as Aphelenchoides ritzemabosi and Ditylenchus dipsaci are major pests of the foliar parts of alfalfa (Gray et al, 1994; Milano de Tomasel and McIntyre, 2001), whereas Meloidogyne spp. and Pratylenchus spp. in particular infect roots of this genus and cause substantial yield losses (Hafez and Sundararaj, 2009). The aim of this investigation was to determine the biodiversity, prominence and seasonal population fluctuations of plant-parasitic tylenchids that occur in soil of alfalfa plants in this province and to identify whether relationships exist between selected soil properties and nematode population densities
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