Pearl Millet as a Rotation Crop for Peanut

Abstract

In the southeastern United States, there are limited options for crops that can be grown in rotation with peanut (Arachis hypogaea). Pearl millet (Pennisetum glaucum) has potential as a grain crop, and some hybrids have shown resistance to the peanut root-knot nematode (Meloidogyne arenaria), the primary nematode pest of peanut in this region. The objective of this study was to determine whether pearl millet reduces M. arenaria when planted in rotation with peanut. The experiment was arranged as a randomized, complete-block design with six replications. The rotations were peanut following either 2 years of corn, HGM-100 pearl millet, or TifGrain 102 pearl millet. There were two staggered sequences of each rotation so that a cycle was completed in 2004 and in 2005. Pearl millet did not increase either stem rot or Rhizoctonia limb rot in peanut. In both years, root galling from M. arenaria was lower on peanut following TifGrain 102 (4.6 on a scale of 0 to 10) and corn (4.9) than following HGM-100 (7.5). Peanut yields in 2004 were low and unaffected by the preceding rotation crop; however, in 2005, yields were greater in peanut following 2 years of TifGrain 102 (2320 kg/ha) and corn (2504 kg/ha) than following HGM-100 (1821 kg/ha). The lower yields following HGM-100 were likely due to greater populations of M. arenaria that had developed on the susceptible pearl millet hybrid. Economic analyses showed greater returns above variable costs from the grain crops than from the peanut crops. We conclude that the resistant pearl millet hybrid TifGrain 102 is as effective as corn in limiting population increase of M. arenaria and in enhancing peanut yield compared to the susceptible pearl millet hybrid, HGM-100. Additional research is needed to improve the profitability of pearl millet, and nematode resistance should be an important component of crop improvement programs. Accepted for publication 20 October 2006. Published 2 February 2007.