Effect of Root-knot Nematodes (Meloidogyne incognita and M. enterolobii) on Root and Shoot Biomass of Psidium cattleianum and Interspecific Hybrid Progenies of Guava

The present experiment was conducted in the Division of Crop Protection at the ICAR-Indian Institute of Horticultural Research, Bengaluru (Karnataka), India during 2022–2023 for nine months to investigate the effect of root-knot nematodes (M. incognita and M. enterolobii) on the biomass of resistant wild parent P. cattleianum, common guava; P. guajava and the interspecific hybrid progenies. Results revealed significant variations in the growth of shoot and root parameters among the parents and hybrid progenies. Reduction in shoot and root weight was recorded in all the susceptible plants whereas, the resistant species recorded increased growth parameters of both shoot and root. In the susceptible plants inoculated with M. enterolobii a drastic reduction in shoot weight, root weight and root length were observed. However, in the resistant wild species (P. cattleianum var. cattleianum and P. cattleianum var, lucidum) the growth of shoot and root was increased as normal. In contrast, it was noticed that the root length was decreased in susceptible plants inoculated with M. enterolobii due to decomposition and deterioration of roots over three to nine months whereas, resistant wild species did not express these kinds of symptoms. Based on the shoot and root growth parameters, this study confirms that M. enterolobii is a more dangerous, devastating and virulent species compared to M. incognita. This indicates that these resistant species have the potential to exploit their resistance in guava breeding, especially the development of resistant varieties.