Improvement of wheat in Zambia using incomplete resistance against rusts

The programme of wheat improvement developed in Zambia used local facilities (finance, personnel, infrastructure), low budget, and few personnel. Incomplete resistance against rusts was used to obtain durable resistance.<br/>The abiotic conditions, socio-economic status of the farmers, cropping methods, economic aims of wheat production and the status of research are described. Pests and diseases are discussed including some which are yet of minor importance. Possible grain yield losses are estimated.<br/>Recent literature on stem and leaf rusts in southern Africa is reviewed; epidemiology of both rusts, race shifts, seasonal variations in development, yield losses, and possible effects of an increase in wheat area are considered. Selections exhibiting stable incomplete resistance may have differential resistance.<br/>Qualitative and quantitative plant characteristics are described and results of trials from various irrigation seasons, are discussed. Selection criteria are given.<br/>Avoidance of differential resistance, selection of parent genotypes. multiple crosses using Ethrel, breeding scenarios, implementation of selection and management of trials are described.<br/>Suitable lines for irrigated, dambo and seepage wheat production were produced within 5 years by means of different scenarios. Resistance to helminthosporium and tolerance to low pH needed improvement, resistance to various pests and diseases was incomplete but adequate.<br/>Opportunities for increasing wheat production in Zambia are discussed, and possible uses of the new lines indicated.<p/>