Abstract:

Plant-parasitic nematodes cause grain yield loss in maize. The most important genera of plant-parasitic nematodes demonstrated to be of economic importance to maize are Pratylenchus spp., Meloidogyne spp. and Heterodera spp. In Uganda, the most prevalent species are Pratylenchus zeae and Meloidogyne spp. The current study was initiated with the following objectives: (i) assessing farmers’ awareness of maize nematodes, other maize production constraints, and desirable agronomic traits; (ii) assessing the efficiency of sterile carrot discs for mass culturing of Pratylenchus zeae; (iii) Characterising the inheritance of nematode resistance in maize, through, estimation of the general combining ability (GCA) of various parents, and the specific combining ability (SCA) of a parent in a cross with another parent; and through determining the contribution of cytoplasmic effects to inheritance of resistance to nematodes; and (iv) determine the level of nematode resistance among F, hybrids and estimate grain yield, heterosis and yield losses associated with maize hybrids under nematode infestation; (v) comparing the gains in nematode resistance and grain yield obtained following two cycles of St progeny recurrent selection in three tropical maize populations. In the participatory rural appraisal, data were collected from 120 households in two maize growing districts. Maize roots and soil samples were also collected from farmers’ fields, and nematode incidence determined. A small percentage (18.5%) of farmers was familiar with nematodes and the damage they cause in maize. Pratylenchus zeae occurred at generally higher frequencies than Meloidogyne spp. in susceptible cultivars. The landraces and the cultivar Longe 5 supported high nematode populations. Farmers also reported that Longe 5 had low yields when compared to the rest of the cultivars. Farmers’ most preferred traits were pest and disease resistance, high grain palatability, long storage duration and large kernels. These findings justify the need for a programme to raise farmers' awareness on nematodes, their effects on crops as well as control strategies, and also a breeding programme that incorporates nematode resistance with farmer-preferred characteristics in maize.