Differences in parasitism of root-knot nematodes (Meloidogyne spp.) on oilseed radish and oat

Abstract

Oilseed radish and oat are cool season annual crops that are potentially used as "trap" or "biofumigant" crops for the suppression of plantparasitic nematodes in soil. Cultivars of oilseed radish (Carwoodi, Cardinal, Final, Image, Concorde, Control, Eco-Till, Karakter and Cannavaro), white (Tachiibuki) and black (Pratex) oats were evaluated for their ability to reduce reproduction of three root-knot nematode species: Meloidogyne javanica, M. incognita race 3, and M. arenaria race 1. Nematode penetration and development were also evaluated using selected resistant and susceptible cultivars under greenhouse conditions. Root galling severity, number of eggs per gram of fresh root, and rate of reproduction varied among the cultivars in response to nematode infection. Oilseed radish cv. Carwoodi was resistant to M. javanica, whereas Karakter and Concorde were maintenance hosts allowing the nematode to maintain or increase its population on the plants. For M. incognita, Control and Carwoodi oilseed radish and Tachiibuki oat were resistant hosts. The cultivars that supported little reproduction of M. arenaria were Karakter and Carwoodi radish, and Tachiibuki oat. Comparable numbers of nematodes entered the roots of susceptible and resistant cultivars of oilseed radish and oat during early stages of infection. However, the development of the nematodes as evident from counting young and egg-laying females in roots were significantly decreased or inhibited in the resistant cultivars compared to the susceptible cultivars indicating that resistance occurs at post-infection stages. Histopathological examinations of galled-root tissues also revealed the susceptibility and resistance responses of selected cultivars of oilseed radish and oat to these nematode species.

Screening of anti-nematode potential through inhibition of egg hatching in plant-parasitic nematode Meloidogyne javanica

“…Phylogenetic studies of nematode genome have provided evidences supporting the evolution of parasitism on various occasions during evolution in plantparasitic nematodes [6]. Similar trend was followed by animal parasitic nematodes as well [7][8][9]. This observation strongly suggests acquisition of favourable gene during evolution of nematodes [10,11].…”

Discovery of a major QTL for resistance to the guava root-knot nematode (Meloidogyne enterolobii) in ‘Tanzania’, an African landrace sweetpotato (Ipomoea batatas)

“…While a RF less than one is, by this de nition, resistant, maintaining nematode populations at or near the initial load is not satisfactory for growers. Ideally, a next-generation sweetpotato variety would be so highly resistant as to be considered a non-host (RF < 0.1), as de ned by Hamidi and Hajihassani (2020). The TB population has demonstrated that this level of resistance is attainable in sweetpotato through a single cross with a resistant parent.…”