Molecular identification and population dynamics of the stem and bulb nematode Ditylenchus dipsaci species on chickpea in Turkey

Ditylenchus dipsaci is a widely distributed, damaging plant-parasitic nematode that attacks most legume crops, especially chickpea. Controlling nematode numbers is important not only for the in-season crop but for the wider rotation as well. The study was set up in a range of Turkish chickpea environments to evaluate the population dynamics of the D. dipsaci in wild and domesticated Cicer spp. to understand whether this new diversity harbors useful resistance. The field study was conducted in contrasting cold, long-season and hot, short-season environments of SE Anatolia (Ankara and Sanliurfa) in 2015/2016 and 2016/2017. A total 211 soil and root samples were collected from 37 districts in 17 provinces of Turkey. Finally, 95 samples (45%) among the 211 samples were selected to identify the race formation population of D. dipsaci using two PCR primers (DdpS2/rDNA2, and DdpS1/rDNA2) during spring and summer 2014–2016. The results on population dynamics indicated that D. dipsaci attack started in February-March on the chickpea cultivars and the population increased gradually with the growth of the plant. The maximum numbers of nematodes were extracted from samples during June to mid-summer (July) and the population densities were at the lowest during cold months winter (February-March). The low population density was observed on lines 232, 323, 412, and 82 to D. dipsaci. 43% of the nematode samples were positive with two primers. Ditylenchus dipsaci sensu stricto was identified with specific primer sets on chickpea in Aegean, Central, Anatolia, Mediterranean and Trace regions in Turkey.