Breeding of maize for fall armyworm resistance in southern Africa

In 2016 sub-Saharan Africa (SSA) was invaded by the transboundary maize-eating pest, fall armyworm [Spodoptera frugiperda (J.E. Smith); FAW]. The pest has threatened food security and livelihoods of the majority of smallholder farmers in the region. The main aim of this study was to investigate the potential of breeding maize with resistance to FAW in southern Africa. The first study aimed to assess the breeding potential of introduced exotic FAW resistant trait donor maize lines with southern Africa germplasm. Thirteen mid-altitude adapted inbred lines were crossed with seven FAW-resistant exotic donor lines, in a line x tester mating scheme that produced 84 F1s which were evaluated together with checks at four locations under natural FAW infestation. The best exotic donor lines with low and negative general combining ability (GCA) effects for foliar FAW damage (FFAWD) resistance scores and good grain yield (GYD) per se performance were CML139, CML67, CML121 and CML345. Local lines that showed similar good attributes were CimExp1, CimExp4, CimExp5, CimExp8 and CimExp10. The best crosses were CimExp1/CML331, CimExp1/CML345, CimExp10/CML331 CimExp5/CML331 and CimExp5/CML345. In the second study, two sets of germplasm (hybrids/OPVs and inbred lines) were evaluated for FAW resistance under managed and natural FAW infestation. The objective was to evaluate commercial and experimental maize hybrids and parental lines cultivated in southern Africa for resistance to FAW. Commercial cultivars were significantly more affected by FAW infestation than experimental hybrids. The introduced FAW-resistant donor lines (CML338, CML67, CML121 and CML334) showed better resistance to FAW damage, individually and in hybrid combinations. Local inbreds, SV1P, CML491 and CML539, also showed good FAW resistance. Husk cover, ear rot, anthesis date and plant height were correlated with FAW resistance. The third study aimed to investigate the stability of grain yield performance and resistance