Pearl Millet and Grain Sorghum Yield Response to Water Supply in Nebraska

Abstract

Pearl millet [Pennisetum glaucum (L.) R. Br.] is a drought‐tolerant crop that may serve as an alternative summer crop in Nebraska. Field experiments were conducted in 2000 and 2001 near Sidney and Mead, NE, to determine the water use efficiency (WUE) and yield response to water supply at critical developmental stages of pearl millet and grain sorghum [Sorghum bicolor (L.) Moench]. Four water regimes were used: (i) no irrigation, (ii) single irrigation at boot stage, (iii) single irrigation at mid–grain fill, and (iv) multiple irrigations. Pearl millet grain yields were 60 to 80% that of grain sorghum. Average grain yields at Mead were 5.1 Mg ha−1 for pearl millet and 6.1 Mg ha−1 for grain sorghum. At Sidney, average pearl millet yields were 1.9 and 3.9 Mg ha−1 in 2000 and 2001, respectively, and average grain sorghum yields were 4.1 and 5.0 Mg ha−1 in 2000 and 2001, respectively. Both crops used a similar amount of water (336 and 330 mm in 2000 and 370 and 374 mm in 2001 for pearl millet and grain sorghum, respectively) and responded to irrigation with a linear increase in grain yield as water use increased. Grain sorghum had greater WUE than pearl millet (12.4–13.4 kg vs. 5.1–10.4 kg grain ha−1 mm−1). Pearl millet, with lower and less stable yields, does not currently have the potential to be a substitute crop for grain sorghum in Nebraska.