EVALUATION OF LANDRACE TOPCROSS HYBRIDS OF PEARL-MILLET FOR ARID ZONEENVIRONMENTS

Pearl millet (Pennisetum glaucum (L.) R. Br.) cultivars for marginal, arid environments need to combine the adaptation to stress conditions of indigenous landraces with an improved yield potential and disease r esistance, to allow them to both perform well in fanners fields and to meet the requirements for cultivar release. This paper evaluates land race-based topcross hybrids (adapted landraces crossed on high-yieldin g male-sterile lines), as a quick and efficient way of achieving this objective. Topcross hybrids showed a consistent increase in biomass pr oduction across all test environments, including the harsh arid zone e nvironments. Depending upon the plant type of the male-sterile used to make the hybrid, this was expressed as increased grain yield only, or increased grain and fodder yields. The downy mildew (Sclerospora gram inicola) reaction of the topcross hybrids was determined by the reacti on of the male-sterile line used, with the resistant male-sterile prod ucing resistant topcross hybrids and vice-versa. Topcrossing adapted l andraces on high-yielding male-sterile lines thus provides an opportun ity to improve disease resistance and grain and/or fodder yields, with no apparent loss of adaptation to the marginal environments in which the landraces have evolved.