Evaluation of resistance to chinch bug in pearl millet in temperate and subtropical environments.

Pearl millet inbreds and hybrids were evaluated for resistance to chinch bug at Lincoln, NE, and Tifton, GA, in 2003 and 2004. Insect feeding damage expressed as plant mortality, stunting, leaf sheath necrosis, and tiller mortality was observed over time. Resistance was expressed by a slower rate of plant damage to resistant genotypes compared to susceptible ones. Across experiments, inbreds 59464B and 59668M-1 were most frequently identified as resistant. Inbred Tift 99B was susceptible in every experiment and by every assessment criterion. The experiments revealed information on the genetic expression of resistance. When insect damage among hybrids made with Tift 454 was compared, resistance tended to be dominant or overdominant in expression. Evidence for location-specific resistance caused by environmental conditions or genetic differences in the insect populations between the two locations was observed. Inbreds 03GH707 and Tift 454, developed at Tifton, were resistant only in some assessments at Tifton, but not at Lincoln. 16RmR1, developed at Lincoln, was susceptible in both Lincoln experiments, but not at Tifton. 03GH706 was susceptible in some Tifton assessments, but was not among the most susceptible inbreds in the Lincoln experiments. Evaluations are needed at multiple locations to effectively identify resistance to damage caused by chinch bug feeding in pearl millet.