An Open Access Journal published by ICRISAT SAT eJournal  ejournal.icrisat.org - 1 - December 2009  Volume 7 Inheritance of chinch bug resistance in grain pearl millet Andrea Maas 1 * and Xinzhi Ni 1,2 1. Soybean Production Research, Monsanto Company, 36142 E. State Route 10, PO Box 33, Mason City, IL 62664, USA 2. Present address: USDA-ARS Crop Genetics and Breeding Research Unit, 2747 Davis Road, Bldg. #1, PO Box 748, Tifton, GA 31793-0748, USA *Corresponding author: andrea.l.maas@monsanto.com Abstract Pearl millet (Pennisetum glaucum) is a promising alternative feed grain for southeastern US crop productions systems because of its ability to reliably produce grain under drought conditions on sandy, acidic and low fertility soils. Chinch bug [Blissus leucopterus leucopterus (Say) (Heteroptera: Blissidae)] infestation was very high under the drought conditions in southern Georgia in 2006 and 2007 when 37 elite inbred breeding lines and 145 hybrids were screened for chinch bug resistance. The objective of this research was to determine if chinch bug resistance existed in current elite inbred parental materials, and if so, what level of inheritance was demonstrated for this trait. In September 2006, 37 inbred lines replicated six times were assessed for resistance under heavy natural chinch bug infestation. In 2007, 145 F 1 hybrid progenies, replicated three times were assessed twice (July 16 and 30) under heavy natural chinch bug infestation. Plots were scored 0 (no damage) to 4 (dead) for insect damage. The damage rating ranged from 1.0 to 2.86 in inbred lines and from 1.0 to 3.3 in hybrids. Seven of the 37 inbred lines and 8 of the 145 hybrids were identified as chinch bug resistant, while seven of the 37 inbred lines and four of the 145 hybrids were identified as the most susceptible to chinch bug infestation. Observed inheritance (h n 2 ) for this population was 0.69 with P <0.001. Introduction Pearl millet (Pennisetum glaucum) is a promising alternative feed grain for southeastern US crop production systems because of its ability to reliably produce grain under drought conditions on sandy, acidic, and low fertility soils (Menezes et al. 1997). Chinch bug [Blissus leucopterus leucopterus (Say) (Heteroptera: Blissidae)] infestation was very high under drought conditions in 2006 and 2007 confirming early predictions by Hudson (1995) that chinch bug would be the most important insect pest on pearl millet grown for grain. Chinch bug is a piercing-sucking insect with multiple generations occurring throughout the growing season (Hudson 1995). The US dwarf grain pearl millet hybrids average 85 days to maturity allowing for a large growing window in southern Georgia or an opportunity for double cropping, but the multiple generations of chinch bug severely limit this if the grower seeks to plant millet to avoid infestation. Additionally pearl millet is typically being grown under yield-limiting conditions such as drought or on low fertility soils making low input costs of critical importance. Zeta-cypermethrin [S-cyano (3- phenoxyphenyl) methyl (+) cis/trans 3-(2,2-dichloro- ethenyl)-2,2 dimethylcyclopropane carboxylate] is labeled for use on pearl millet, but it can account for as much as 15% of the variable costs of production (Lee et al. 2004). Additionally chinch bugs are difficult to control due to the lush growth of pearl millet and the insect’s preference to inhabit the inside of the leaf sheath unless populations are exceptionally high (Hudson 1995). Because of these factors natural host plant resistance would provide the best form of insect control. The objective of this research was to determine if chinch bug resistance exists in 37 current elite parental inbred lines, and if so what level of inheritance was demonstrated for this trait in the related hybrids. Materials and methods Thirty-seven elite inbred breeding lines from a diverse background developed by the USDA-ARS pearl millet breeding program at Tifton, Georgia, USA, and 145 F 1 Citation: Maas A and Ni X. 2009. Inheritance of chinch bug resistance in grain pearl millet. Journal of SAT Agricultural Research 7.