Drought response of pearl millet landrace-based populations and their crosses with elite composites

Drought is the primary constraint in pearl millet (Pennisetum glaucum) production in the drier semi-arid and arid regions of south Asia and Africa. The traditional landraces from drier regions are good sources of drought adaptation but often lack high yield under near-optimum growing environments. The objective of this paper was to assess whether crosses between landrace populations and elite germplasm can produce hybrids with better grain yield under favourable conditions than landraces, without compromising grain yield under drought. The research evaluated 20 crosses and their nine parents (consisting of landrace-based populations and elite composites) under drought and non-drought conditions. Drought response index (DRI), based on flowering and grain yield measured in drought and non-drought environments, was used to assess drought tolerance. Landrace populations yielded significantly more grain under drought stress than elite composites and crosses and had the highest mean DRI (3.99). In contrast, composites showed maximum sensitivity to drought with significantly negative DRI (-3.64). Adaptation to either drought or high productivity conditions appeared to be associated with different plant types: higher panicle number, lower grain number per panicle, and smaller seed size were associated with drought adaptation; low tillering and greater number of large-sized seeds per panicle were favoured for optimum growing conditions. Crosses yielded significantly better than composites under drought, better than landrace populations under non-drought and had a wide range in drought sensitivity. Around 40% of crosses produced on average 23% higher grain yield than the best landrace under favourable conditions, without compromising grain yield under drought. The results illustrate that hybridization of landrace populations with elite composites can produce germplasm that combines drought tolerance of traditional material with high production potential of elite genetic material.