PLANT RESISTANCE Performance of Crosses Among Flint Maize Populations Under Infestation by Sesamia nonagrioides (Lepidoptera: Noctuidae) P. SOENGAS, A. BUTRO ´ N, P. REVILLA, A. ORDA ´ S, AND R. A. MALVAR Misio ´ n Biolo ´ gica de Galicia, Consejo Superior de Investigaciones CientiÞcas, Apartado 28, E-36080 Pontevedra, Spain J. Econ. Entomol. 97(4): 1438Ð1443 (2004) ABSTRACT Flint maize, Zea mays L., varieties provide some interesting agronomic characteristics and kernels that possess a better ability than other kernels for developing high-quality ßour. The pink stem borer, Sesamia nonagrioides Lefebvre, is an important constraint for the maize crop in Medi- terranean regions. The objective of this work was to identify a “ßint  ßint” heterotic pattern that wouldperformwellunderartiÞcialinfestationby S. nonagrioides.A10-populationdiallelwasevaluated under infestation by S. nonagrioides in 2 yr. Variety effects were the only signiÞcant effects involved in stem and ear resistance to S. nonagrioides attack. Variety effects and average heterosis effects were the only signiÞcant effects for grain yield under artiÞcial infestation conditions. Considering variety effects and cross-performance, the heterotic pattern Basto/Enano levantixo  Longfellow (BA/EL  LO) would be recommended for obtaining ßint maize hybrids tolerant to S. nonagrioides attack because BA/EL had the most favorable variety effects for stem resistance, LO exhibited the most positive variety effects for grain yield, and the cross BA/EL  LO yielded signiÞcantly more than the remaining crosses. KEY WORDS Zea mays, Sesamia nonagrioides, pink stem borer, resistance, heterotic pattern THE PINK STEM BORER, Sesamia nonagrioides Lefebvre, is the main pest of maize, Zea mays L., in northwestern Spain (Cordero et al. 1998). The majority of larval development takes place inside the maize plant and can cause stem lodging, ear drop, and direct yield losses (Anglade 1961). Maize yield losses averaged on a set of 45 hybrids was 15% of the yield of the insect- free crop (Butro ´ netal.1999b).Larue(1984)reported that yield losses could reach up to 30%. The use of maize-resistant and tolerant cultivars seems to be one of the most promising methods within an integrated pest management (IPM) framework (Ortega et al. 1980, Pathak 1991). As a prerequisite step to develop resistant and tolerant cultivars, it is necessary to Þnd sources of resistance and tolerance. Many efforts have been devoted to this end, but just a small part of the maize germplasm susceptible to be used in the areas affected by the S. nonagrioides attack has been tested (Malvar et al. 1993, 2004; Cartea et al. 1994; Butro ´ n et al. 1998a, 1999a,b; Velasco et al. 1999a,b). In Europe, most maize hybrids come from the cross between European ßint and American dent maize inbreds (Moreno-Gonza ´ lez 1988, Orda ´ s 1991). European ßint maize material supplies adaptation to European con- ditions, whereas American dent maize brings high yield potential. European ßint maize varieties provide characteristics such as early vigor, earliness, resistance to stem lodging, and resistance to drought stress. In addition, ßint kernels possess a better ability than other kind of maize kernels for developing high-qual- ity ßour. Therefore, the high-quality ßour producers “ßint  ßint” maize hybrids could be a good alterna- tive to the most common hybrids used in Europe, “European ßint  American dent,” mostly in regions where earliness is required. Because S. nonagrioides is a yield limiting factor, those possible ßint  ßint het- erotic patterns should be tested for resistance and tolerance against S. nonagrioides infestation. Some Spanish ßint maize populations along with other populations were previously evaluated for re- sistance to S. nonagrioides attack by Malvar et al. (1993). The ßint maize population Amarillo temprano de Arago ´ n was the most resistant to stem attack by S. nonagrioides. Populations have not been tested for tolerance, calculated as the percentage of yield loss = ((1 - yield of infested plants/yield of no infested plants) * 100), to S. nonagrioides attack. Butro ´ n et al. (1999b) found lack of concordance among general combining ability (GCA) effects for stem resistance, grain yield loss, and grain yield under infestation con- ditions, and low correlation between speciÞc combin- ing ability (SCA) effects for grain yield under artiÞcial infestation and noninfested conditions. Then, it was suggested that yield under artiÞcial infestation con- ditions would be the best trait for evaluating the level of defense (including resistance and tolerance) against S. nonagrioides attack. The objective was to identify a “ßint  ßint” heterotic pattern that could perform well under artiÞcial infestation by S. nona- grioides. 0022-0493/04/1438Ð1443$04.00/0  2004 Entomological Society of America Downloaded from https://academic.oup.com/jee/article/97/4/1438/2218112 by guest on 28 June 2022