Yield and physiological aspects of 17 varieties of corn grown in runoff farming

Abstract

A micro-catchment water harvesting agrisystem in Avra Valley, west of Tucson, Arizona, was utilized to grow 17 varieties of drought tolerant corn (Zea mays). The primary objective of this study was to isolate and evaluate the grain yield performance of these cultivars. Additional measurements were also taken on transpiration rate (TR), leaf water potential (0), stress degree day (SDD), and crop water stress index (CWSI), during the period 24 October to 2 November, between two irrigations, in search of possible physiological mechanisms of drought adaptability and their impact on production. The system's performance in terms of economical crop growth is subject to further research. The analysis of grain yield indicates a significant varietal difference. Physiological parameters monitored also show trends of differences among cultivars. It was found that cultivars capable of maintaining a higher plant water content, by preserving their TR, Ψ1, CWSI, and SDD are not necessarily the better yielding cultivars. Possible justifications of this phenomena are discussed. It is suggested that a distinction has to be made between crop adaptability to drought and preservation of a high grain yield since under limited moisture conditions, one might be attained through the suppression of the other.