Genetic variation and diversity of pearl millet [Pennisetum glaucum (L.)] genotypes assessed for millet head miner, Heliocheilus albipunctella resistance, in West Africa

Pearl millet (Pennisetum glaucum L.), the major source of minerals and dietary energy for people living in the semi-arid regions of Sahel, is regularly damaged by millet head miner, Heliocheilus albipunctella. In order to identify the plant-based resistance sources for millet head miner along with high grain Fe and Zn, we have screened forty pearl millet genotypes, using an artificial infestation method. Analysis of variance revealed significant differences in the genotypes tested for head miner resistance. The genotypes Gamoji, ICMP 177001, ICMP 177002, ICMV 177003, ICMV IS 90311, LCIC9702, Souna 3, ICMV IS 94206 and PE08043 exhibited antibiosis resistance mechanism to Heliocheilus albipunctella with appreciable agronomy and grain yield when compared with the susceptible check ICMV IS 92222. The genotypes Faringuero, ICMV 167005, ICMV IS 99001, Sadore local, SOSAT-C88, and ICMP 177004 exhibited tolerance to head miner damage with good per se performance. The genotypes ICMP 177001, ICMP 177002, ICMV 177003, and Moro exhibited resistance to millet head miner and had consistent grain Fe content across seasons (ranging from 44 to 70 ppm). Association between the head miner resistance and morphological traits showed a positive and significant correlation of larval production index (%) with head miner damage (r = 0.59**). Grain Fe and Zn contents exhibited negative association with panicle length and grain yield indicating proper care should be taken in breeding for these traits. Hence, the identified resistance sources can be effectively utilized in breeding head miner resistant pearl millet OPV’s/ hybrids, with high grain yield including Fe and Zn concentrations, to overcome the hunger and malnutrition seen in populations living in the semi-arid tropics

Assortative Mating between European Corn Borer Pheromone Races: Beyond Assortative Meeting

BACKGROUND: Sex pheromone communication systems may be a major force driving moth speciation by causing behavioral reproductive isolation via assortative meeting of conspecific individuals. The 'E' and 'Z' pheromone races of the European corn borer (ECB) are a textbook example in this respect. 'Z' females produce and 'Z' males preferentially respond to a 'Z' pheromone blend, while the 'E' race communicates via an 'E' blend. Both races do not freely hybridize in nature and their populations are genetically differentiated. A straightforward explanation would be that their reproductive isolation is a mere consequence of "assortative meeting" resulting from their different pheromones specifically attracting males towards same-race females at long range. However, previous laboratory experiments and those performed here show that even when moths are paired in a small box - i.e., when the meeting between sexual partners is forced - inter-race couples still have a lower mating success than intra-race ones. Hence, either the difference in attractivity of E vs. Z pheromones for males of either race still holds at short distance or the reproductive isolation between E and Z moths may not only be favoured by assortative meeting, but must also result from an additional mechanism ensuring significant assortative mating at close range. Here, we test whether this close-range mechanism is linked to the E/Z female sex pheromone communication system. METHODOLOGY/PRINCIPAL FINDINGS: Using crosses and backcrosses of E and Z strains, we found no difference in mating success between full-sisters emitting different sex pheromones. Conversely, the mating success of females with identical pheromone types but different coefficients of relatedness to the two parental strains was significantly different, and was higher when their genetic background was closer to that of their male partner's pheromone race. CONCLUSIONS/SIGNIFICANCE: We conclude that the close-range mechanism ensuring assortative mating between the E and Z ECB pheromone races is unrelated to the difference in female sex pheromone. Although the nature of this mechanism remains elusive, our results show that it is expressed in females, acts at close range, segregates independently of the autosome carrying Pher and of both sex chromosomes, and is widely distributed since it occurs both in France and in the US

Biological control of the millet head miner Heliocheilus albipunctella in the Sahelian region by augmentative releases of the parasitoid wasp Habrobracon hebetor: effectiveness and farmers’ perceptions

On-farm augmentative releases of the parasitoid Habrobracon hebetor (Say) for controlling the millet head miner (MHM) Heliocheilus albipunctella (de Joannis) were tested in Burkina Faso, Mali and Niger from 2007 to 2009. In addition, a survey of farmers’ perceptions of insect pests, with particular focus on MHM, and the biological control program (BCP) was carried out. There was a significant increase of MHM parasitization rate after the releases, with up to 97% mortality. The survey on farmers’ perceptions revealed a fair knowledge of the MHM and the ability of farmers to describe the pest and the damage it caused. Farmers claimed that the biocontrol agent H. hebetor is effective and perceived a significant gain in grain yield due to this control strategy. Implications of these findings for a large extension of the MHM biocontrol program are discussed