Inheritance of antibiosis to Sesamia nonagrioides (Lepidoptera : Noctuidae) in maize

The stem borer Sesamia nonagrioides (Lefebvre) is the main pest of maize, Z en mays L., in northwestern Spain. The inheritance of the stalk resistance to this maize borer is unknow. The objective of this work was to study the inheritance of antibiosis to Sesamia in maize stalks. Three maize inbreds w ith different stalk resistance levels to S. nonagrioides were used and 2 cr osses were made: CM109 X EP31 (resistant X medium resistant) and CM109 X EP 42 (resistant X susceptible). For each cross, 6 generations, consisting of the P-1, P-2, F-1, F-2, and backcrosses (BC1 and BC2), were evaluated for 2 yr. Additive, dominance, epistatic, environmental effects, and the genotyp e X environment interaction were estimated from generation mean analysis. C orrelation coefficients among stalk damage traits showed that tunnel length was a good indicator of stalk resistance to Sesamia. The inheritance of st alk resistance to Sesamia is under genetic control. The additive-dominance model without nonallelic and genotype X environment interactions fit the ge neration mean analysis for both crosses, but gene action differed from one cross to another. For the cross CM109 X EP31, the additive and dominance ge ne effects were significant and had. in general, similar importance; wherea s for CM109 X EP42, stalk resistance involved largely additive effects. A r ecurrent selection approach should be used to improve resistance to Sesamia combining additive and dominance gene effects or considering only additive effects, depending on the cross evaluated. Resistance was dominant to susc eptibility. The resistant inbred CM109 could be used as a donor of stalk re sistance.