Host status of rotation crops in Asian rice-based cropping systems to the rice root-knot nematode Meloidogyne graminicola

Abstract

Rotation with nonhost crops is an important practice used for root-knot nematode (RKN) management. Screenhouse experiments were conducted to evaluate the response infection of 27 cultivars belonging to 14 crops (blackgram, cabbage, cauliflower, chickpea, cowpea, garlic, ginger, greengram, groundnut, maize, potato, sesame, soybean, sunflower), which are grown in rotation with rice in lowland and upland rice-based ecosystems, to the RKN Meloidogyne graminicola. Root galling indices observed on all crop rotation cultivars were significantly lower compared with the rice cv. Thihtatyin, used as positive control. Differences in host response to M. graminicola infection were observed between cultivars. All 27 cultivars were poor or nonhosts of M. graminicola, except cv. Yezin 4 of chickpea considered as good host. No significant differences in plant growth were observed between non-inoculated and inoculated plants of all plant/species cultivars, with the exception of a reduction in root length in the chickpea cv. Yezin 4 (good host) and the garlic cv. Shan (poor host). Rotation crops identified as poor or non-hosts of M. graminicola could be useful in the management of RKN in rice-based cropping systems.

Adult-plant resistance of Panax notoginseng to nematodes and interspecific facilitation with pine trees

“…In December 2018, the P. notoginseng seedlings were harvested at ve uniformly distributed survey sites, and the soil was shaken off the roots. The severity of RKN of the root system was visually assessed for each plant by rating the percentage of roots with root tip galls, and it was based on the RKN rating chart of Bridge and Page, with slight modi cations (Table 1) (Page et al 1982;Win et al 2015;Ulloa et al 2016). Subsequently, the P. notoginseng seedlings of each RKN infestation level were separated into aboveground shoot and belowground root parts, and the roots were divided into large (fresh weight > 3 g), medium (fresh weight between 2 ~ 3 g), and small (fresh weight < 2 g) roots.…”