Genotypic variation for maize weevil resistance in eastern and southern Africa maize inbred lines

Abstract

The maize weevil (Sitophilus zeamais Motschulsky) is the most destructive storage insect pest of maize (Zea mays L.) worldwide, especially among susceptible varieties. Breeding for grain resistance against the weevil is a major component of an integrated pest management strategy in maize production. The objective of this study was to identify diverse sources of weevil resistance for introgression in breeding programmes. A total of 180 inbred lines from three geographical areas were screened for maize weevil resistance. Screening was executed by infesting 50 g of maize grain with 32 newly emerged adult weevils, placed in 250 cm 3 glass jars in a "no-choice" laboratory test. The grain susceptibility parameters used were F 1 weevil progeny emergence, percent grain damage, median development period, Dobie's index of susceptibility, and parental weevil mortality. New sources of weevil resistance for maize breeding were identified. Eight inbred lines were consistently resistant and, therefore, selected as potential donors for weevil resistance in the maize improvement programmes. There was significant genetic variation, and high levels of heritability (89 -96%) for weevil resistance that suggested high potential for germplasm improvement through selection. No significant association was observed between maize weevil resistance and grain yield, suggesting that breeding for maize weevil resistance can be achieved without compromising grain yield.

Factors Influencing Genomic Prediction Accuracies of Tropical Maize Resistance to Fall Armyworm and Weevils

“…In Africa, tremendous efforts were made during the last two decades to build host plant resistance to insect pests in maize through traditional pedigree (phenotypic)-based selection (PS) with substantial desirable results. Several Africa-adapted maize lines were developed and successfully tested for resistance to MW damage on grains [ 7 , 8 , 9 , 10 , 11 , 12 ]. Some of the success stories are from the International Center for Maize and Wheat Improvement (CIMMYT) of Kenya through the Insect Resistant Maize for Africa project (IRMA) that produced several storage pest and stem borer resistant maize lines [ 7 , 8 , 13 , 14 , 15 ].…”

Genomic Prediction of Tropical Maize Resistance to Fall Armyworm and Weevils: Genomic Selection Should Focus on Effective Training Set Determination

“…In Africa, tremendous efforts were made during the last two decades to build host plant resistance to insect pests in maize through traditional pedigree (phenotypic)-based selection (PS) with substantial results. Several Africa adapted maize lines were developed and successfully tested for resistance to MW damage on grains MW damage on grains (7)(8)(9)(10)(11)(12). Some of the success stories are from the International Center for Maize and Wheat Improvement (CIMMYT) of Kenya through the Insect Resistant Maize for Africa project (IRMA) that produced several storage pest and stem borer resistant maize lines (7,8,(13)(14)(15).…”