Resistance of tropical maize genotypes to the larger grain borer

Abstract

Post-harvest losses caused by the larger grain borer (LGB, Prostephanus truncatus) aggravate food insecurity among small-scale farmers. Host plant resistance is a method of LGB control which should be prioritized in order to reduce these losses. The objective of this study was to assess maize resistance to the larger grain borer and recognize some potential causes of resistance. One hundred and sixty-three (163) genotypes were tested; these included 85 hybrids, 2 checks, 6 open pollinate varieties, and 70 landraces, among them gene bank accessions. Grain biochemical content, (protein, oil and starch) and insect resistance parameters, (percentage grain damage, weight loss, flour weight, and number of emerged insects) were measured. There were significant differences (P \ 0.001) among the genotypes for all the traits measured except number of insects. The most resistant hybrids were CKPH08024, CKPH08009, CKPH08012, CKPH08014, CKP08033, CKPH08026, CKPH08014, and CKPH08003. The most resistant landrace accessions were BRAZ 2451, GUAT 1162, BRAZ 2100, and GUAN 36. The percentage weight loss was found to be the most important resistance trait for discriminating among genotypes for it had the largest canonical coefficient. Protein content had higher contribution to variation in resistance to the larger grain borer and this probably contributed to the grain hardness which is a putative trait of resistance to storage pests. The LGB-resistant germplasm could be used for the development of an integrated pest-management program against the LGB.

Varietal susceptibility of maize to larger grain borer, Prostephanus truncatus (Horn) (Coleoptera; Bostrichidae), based on grain physicochemical parameters

“…However, variety factor had a significant effect on susceptibility parameters such as number of emerged insects, median development time, percent of grains attacked, percent of grains weight loss and susceptibility index. The current study indicate also that the number of emerged adults is positively related to attacks and weight loss percents of grains, which is consistent with previous work [22,54]. Early-Thaï, SWAN and Tzee-Yellow varieties that had the lowest susceptibility index (resistant varieties) have recorded few insects emergence in F 1 and exhibited lowest percents of attack and weight loss of grains.…”

IDENTIFICATION OF MAIZE LANDRACES WITH HIGH LEVEL OF RESISTANCE TO STORAGE PESTS Sitophilus zeamais Motschulsky AND Prostephanus truncatus Horn IN LATIN AMERICA

“…Present results confirm the fact that LGB causes major losses compared to MW, as formerly proposed by Meikle et al (1998). Levels of resistance were higher compared with previous studies (Bergvinson, 2001;Kumar, 2002;Mwololo et al, 2012).…”

Comparison of the processing and quality of tortillas produced from larger grain borer Prostephanus truncatus (Horn.) resistant and susceptible maize genotypes

“…This insect preferably feeds from the germ, the main reservoir of crude fat, instead of the endosperm, where starch and gluten proteins are located. These behaviors also contrast with a recent report of mechanism of resistance in P. truncatus where Mwololo et al (2012) show a positive correlation between the quantities of protein and fat with P. truncatus resistance.…”