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

Abstract

The maize weevil (MW) (Sitophilus zeamais), and the larger grain borer (LGB) (Prostephanus truncatus) are major storage pests causing serious losses in maize (Zea mays L.) in developing countries of Latin America (LA). This study identified maize landraces with high levels of resistance to MW and LGB by screening 1171 genotypes collected from 24 LA countries in 38 sampling areas. Maize grain weight losses (GWL), total dust production (TDP) and number of adult progeny (NAP) were measured for LGB and MW attack in each genotype. Susceptibility traits to MW and LGB were related to specific geographical location. Range of resistance for MW was from 0.6 to 51 %, while for LGB from 0.1 to 66 %. Approximately 28 % of the analyzed genotypes showed high level of resistance to MW, with Antilles region offering the most resistant accessions with races of EarCar, Chande, Haitye, Nal-Tel, Tuson, and Canill. Resistance to LGB was observed in 22 % of genotypes analyzed with accessions from Southern México with races of Cónico, Nal-Tel, Vandeño, Elotes Occidentales, Cubano, Tuxpeño, and Tepecintle. Low correlation (r = 0.28; P < 0.01) between maize resistance to MW and LGB indicated a divergent adaptive response of maize grain to these two pest. Geographic data showed a negative correlation between latitude and longitude with MW resistance traits being significant only for longitude (r = -0.253; P < 0.05). Opposite trend of correlations, positive but not significant, was observed for LGB resistance traits. These results indicate an influence of geographic location in local varieties being selected for storage pest resistance over time. Genotypes with excellent postharvest insect resistance have now been identified for maize breeders to use in developing improved cultivars for use in LA.The maize weevil (MW) (Sitophilus zeamais), and the larger grain borer (LGB) (Prostephanus truncatus) are major storage pests causing serious losses in maize (Zea mays L.) in developing countries of Latin America (LA). This study identified maize landraces with high levels of resistance to MW and LGB by screening 1171 genotypes collected from 24 LA countries in 38 sampling areas. Maize grain weight losses (GWL), total dust production (TDP) and number of adult progeny (NAP) were measured for LGB and MW attack in each genotype. Susceptibility traits to MW and LGB were related to specific geographical location. Range of resistance for MW was from 0.6 to 51 %, while for LGB from 0.1 to 66 %. Approximately 28 % of the analyzed genotypes showed high level of resistance to MW, with Antilles region offering the most resistant accessions with races of EarCar, Chande, Haitye, Nal-Tel, Tuson, and Canill. Resistance to LGB was observed in 22 % of genotypes analyzed with accessions from Southern México with races of Cónico, Nal-Tel, Vandeño, Elotes Occidentales, Cubano, Tuxpeño, and Tepecintle. Low correlation (r = 0.28; P < 0.01) between maize resistance to MW and LGB indicated a divergent adaptive response of maize grain to these two pest. Geographic data showed a negative correlation between latitude and longitude with MW resistance traits being significant only for longitude (r = -0.253; P < 0.05). Opposite trend of correlations, positive but not significant, was observed for LGB resistance traits. These results indicate an influence of geographic location in local varieties being selected for storage pest resistance over time. Genotypes with excellent postharvest insect resistance have now been identified for maize breeders to use in developing improved cultivars for use in LA.

Postharvest insect resistance in maize

“…1) (APHLIS, 2017; CABI, 2017; EPPO, 2017). P. truncatus has an enormous impact on the agriculture due to its voracious behavior (Abass et al, 2014;García-Lara and Bergvinson, 2013;Midega et al, 2016). In Latin America, losses caused by this pest can be as high as 50e80% (García-Lara and Bergvinson, 2013;Kumar and Kalita, 2017).…”

“…P. truncatus has an enormous impact on the agriculture due to its voracious behavior (Abass et al, 2014;García-Lara and Bergvinson, 2013;Midega et al, 2016). In Latin America, losses caused by this pest can be as high as 50e80% (García-Lara and Bergvinson, 2013;Kumar and Kalita, 2017). In Western Kenya, 84% of farmers experienced severe losses in stored maize caused by P. truncatus (Midega et al, 2016), while in Tanzania these losses reached 56.7% (Abass et al, 2014).…”

“…International breeding efforts have endeavored to develop high yield insect-resistant maize varieties (Abebe et al, 2009;Tefera et al, 2013Tefera et al, , 2016, using maize landraces as natural sources of resistance, which are also adapted to the farming conditions of the target regions. (Arnason et al, 1994;Abebe et al, 2009;García-Lara and Bergvinson, 2013;Midega et al, 2016;Mikami et al, 2012;Tefera et al, 2016). Thus, the knowledge of the mechanisms and molecular bases of the natural resistance is crucial to the identification of resistance traits, which can be used in high-yield insect-resistant varieties.…”

Frequency and time pattern differences in acoustic signals produced by Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae) and Sitophilus zeamais (Motschulsky) (Coleoptera: Curculionidae) in stored maize

“…The larger grain borer Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae) and the maize weevil Sitophilus zeamais (Motschulsky) (Coleoptera: Curculionidae) are the main damaging storage insect pest for maize (García-Lara and Bergvinson, 2013) regionally. The P. truncatus is more injurious, and in endemic situations, extensive grain damage results in over 30% dry weight loss losses (Farrell and Schulten, 2002;Borgemeister et al, 2003).…”

“…Acoustic devices enable non-destructive, automated detection, and monitoring of insect infestations in grain (Fleurat-Lessard, 1988;Weinard, 1998, Gobernado et al, 2005Schwab and Degoul, 2005;Eliopoulos et al, 2015), including pre-emergent stages of postharvest pests Kiobia et al, 2015). These devices can be incorporated in continuous insect pest surveillance during storage and at ports of exit/entry during grain trade.…”