Submitted to: International Sorghum and Millets Newsletter
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 17, 2000
Publication Date: December 1, 2000
Citation: Wilson, J.P., Ouendeba, B., Hanna, W.W. 2000. Diallel analysis of chinch bug damage to pearl millet. International Sorghum and Millets Newsletter 41:78-91. Interpretive Summary: Forage and turf grasses are frequently damaged by chinch bug in the central, eastern, and southern United States. The insects suck plant juices from the base of the stem, behind leaf sheaths, and in leaf whorls, resulting in wilted, stunted or dead plants. Chinch bug damage has become widespread in pearl millet in the southeastern U.S. A severe infestation at tTifton, GA in 1990 provided an opportunity to determine if resistance to chinch bug damage existed in pearl millets from Africa. This study reveals that heritable resistance to damage from chinch bug feeding exists and is recessive or additive in expression. Cultivars with genetic resistance can be developed with appropriate selection techniques.
Technical Abstract: Five pearl millet varieties from west African countries and 10 F1 populations from diallel crosses between the parental populations were planted in four-row plots in a randomized complete block with five replications at Tifton, GA in 1990. The expeiment was severly infested with and expressed damage by chinch bug [Blissus leucopterus leucopterus (Say)]. .The percentage of necrotic foliage in the center two rows of each plot was visually estimated. Data were analyzed by Gardner and Eberhart's diallel analysis III. Necrosis ranged from 17.3 to 25.2% on parents and from 21.4 to 35.6% on F1s. One F1 population had greater necrosis than both parents, and four F1 populations expressed significantly more foliar necrosis than their more resistant parent. These results indicate a recessive or additive expression of resistance. Necrosis in the remaining F1 populations was greater than either parent, but differences from the more susceptible parent were not significant. General combining ability effects of Exbornu and Ugandi were significant. The general combining ability variance was significant, but specific combining ability variance was not. In these populations, only additive genetic variance contributed to the population genotypic variance for susceptibility to chinch bug damage.