Evaluation of root-lesion nematode (Pratylenchus zeae) resistance assays for sugarcane accession lines

Abstract

No sugarcane cultivar is resistant to root-lesion (Pratylenchus zeae) nematode in Australia. Sugar Research Australia commenced a research project to evaluate new sets of accession lines derived from introgression breeding between wild relatives of sugarcane and commercial parents. No established method of assessment was available for comparing the resistance of sugarcane in the glasshouse. This study aimed to determine the most suitable assessment method for comparing resistance in accession lines. Two resistance parameters were measured, (i) number of nematodes per plant, and (ii) number of nematodes per g of roots. Nine screening trials were conducted from 2011 to 2020. Resistance parameter number of nematodes/plant had less variations within trials compared to nematodes/g roots, although both parameters were equally repeatable. Number of nematodes/g of root were negatively correlated (r = ‒0.29 to ‒0.86, p ≤ 0.001) with root biomass in all nine trials, and with shoot biomass in three out of seven trials (r = ‒0.23 to ‒0.31, p ≤ 0.05). In contrast, the number of nematodes per plant were positively correlated with shoot biomass (r = 0.25–0.53, p ≤ 0.05) in three out of seven trials and with root biomass (r = 0.17–0.27, p ≤ 00.05) in three out of nine trials. These results clearly indicated that nematodes per g root is related to reduction in root biomass and shoot biomass.

Penetration and Development of Meloidogyne javanica on Four Pistachio Rootstocks and Their Defense Responses

“…Shoot and root biomass have already been used to assess the reaction of rootstocks ( Stirling et al, 2011 ). Bhuiyan and Garlick (2021) stated in sugarcane plants infected with M. javanica , if plants with similar root biomass have different number of nematodes, then the difference is most likely due to different levels of resistance, but if a plant has smaller root system, the lower number of nematodes could be due to the limitations in the root biomass. So, it may be more desirable to compare shoot and root biomass of inoculated and uninoculated plants of the same rootstocks to assess the resistance level.…”

Understanding Molecular Plant–Nematode Interactions to Develop Alternative Approaches for Nematode Control

“…Moreover, the majority of plant resistance genes used are effective against only the above-mentioned sedentary nematode category [30,33,42]. Hence, introgression of R-genes to confer nematode resistance to susceptible plants via classical genetic breeding can offer potent steps change in crop productivity [43][44][45]. Admittedly, plant genes responsible for PPN resistance are very useful in lowering PPN population levels, enhancing crop yields, and developing effective crop sequences.…”