Productivity, morphology, phenology, and physiology of a desert-adapted Native American maize (Zea mays L.) cultivar
Author(s)Muenchrath, Deborah Ann
Agronomy and Crop Sciences
Ecology and Evolutionary Biology
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AbstractWater is the single most limiting resource for crop production. Increasing demands for water by agricultural and non-agricultural users, together with recurring droughts, necessitate research to maintain and improve rainfed crop productivity. Basic understanding of agroecosystems that have persisted in arid environments will contribute to development of drought-resistant cultivars and ecologically sound production practices for arid and drought-prone regions. Native Americans of the arid southwestern U.S. and northern Mexico developed agricultural systems that provided viable levels of production within environmental constraints for centuries. This research was conducted to identify biological attributes contributing to the reputed drought resistance of a traditional maize cultivar, and to determine the effects of production practices on maize productivity under arid conditions. The study examined the responses of Tohono O'odham maize, a landrace native to the Sonoran Desert, and a modern hybrid, adapted to the North Central U.S., to five irrigation regimes. Responses were evaluated in the contexts of traditional indigenous and modern commercial planting geometries and depths. Dry matter production and partitioning, morphology, phenology, and stomatal behavior of these cultivars were evaluated. Tohono O'odham maize had higher harvest indices and lower, but more stable, grain yields per unit land area, and produced more grain per unit leaf area compared to the hybrid. The native maize produced smaller plants and leaves, tillered, and tended to be prolific. Tohono O'odham maize emerged and developed more rapidly, and flowered earlier than the hybrid. Both cultivars emerged and flowered earlier when grown in the hill pattern than in the row geometry. In the drier season, flowering was accelerated in the native maize and delayed in the hybrid. Tohono O'odham maize maintained a short anthesis-to-silking interval. Each year, seasonal mean stomatal conductance and transpiration rates were greater in Tohono O'odham maize than the hybrid, with the native maize exhibiting lower rates during the vegetative phase and greater rates during flowering and early grain-fill. The drought resistance of Tohono O'odham maize is attributable to a combination of small plant size, phenological and reproductive plasticity, and stomatal responsiveness.