Resistance Breeding for Northern Corn Leaf Blight with Dominant Genes, Polygene, and Their Combinations—Effects on Disease Traits

Resistance breeding is the most effective method to control northern corn leaf blight (NCLB). The objectives were (1) Assess effects of dominant genes (Ht(s)), polygene (PG), and their combinations disease rating (DR), number lesions per (NLPL), lesion size (LS); (2) Estimate genetic components, general combining abilities (GCA), heritability under two Line × Tester analyses; (3) Determine gene action through mid-parent heterosis (MPH) better-parent heterobeltiosis (BPH) analysis. A total 163 genotypes, including 120 crosses, parents, 10 hybrid checks, evaluated NCLB artificial inoculations in 2015 2016. results indicated that PG had best resistance DR, NLPL, LS followed by PGHt(s) single Ht(s). Ht1 both resistant susceptible lesions. Ht2 Ht3 expressed more significantly, while Htm1 Htn1 NLPL. Htm1/Ht2, PG/Htm1, other 11 found excellent for resistance. analysis showed additive important, GCA Ht(s) reduced traits. However, lower narrow sense low. MPH BPH over-dominant actions existed DR