Genetic responses of single crosses of maize to Striga hermonthica (Del.) Benth. and Striga asiatica (L.) Kuntze

Striga hermonthica (Del.) Benth. and Striga asiatica (L.) Kuntze infest millions of hectares of land under cereals in sub Saharan Africa, threatening food security. One of the major crops threatened is maize (Zea mays L.), a staple food for many Kenyans. A diallel cross involving 16 inbred lines was used to study the genetics of resistance to S. hermonthica and S. asiatica. Three inbred lines each from TZL comp 1, Zea diploperennis Iltis, Doebley & Guzman X Zea mays (Diplo pool), and a low emergence stimulant pool (LE Pool) classified as resistant were crossed to adapted but susceptible inbred lines CML-204, CML-373, and CML-395 from CIMMYT and MUG-1, MUG-2, MUG-3, and MUG-4 from Kenya. The hybrids were evaluated for two seasons at Matuga for S. asiatica and at Kibos and Alupe for S. hermonthica. General combining ability mean squares were higher than specific combining ability mean squares for all traits for the two species, indicating additive genetic effects were more important. Inbreds producing crosses with better resistance than the local checks were identified for both Striga species. Diplo pool and LE Pool were better sources of resistance to S. hermonthica and LE Pool and TZL pools were better sources of resistance or tolerance to S. asiatica.