Resumen

GONZALEZ HUERTA, Andrés et al. Grain yield of maize genotypes under rainfed conditions and their relation to ear rot. Agric. Téc. Méx [online]. 2007, vol.33, n.1, pp.33-42. ISSN 0568-2517.

At the Toluca-Atlacomulco Valley, in the State of Mexico, Mexico, 250 000 ha of maize are annually sown mainly with landrace s belonging to races adapted to this highland region. The obj ectives of this study were to evaluate the susceptibility of 25 maize genotypes to Fusarium spp. and to determine its relationship with days to female flowering, stalk and root lodging, ear-rot and grain yield. The genotypes were grown during 2004 at three locations under natural disease incidence in a randomized complete block design with four replications. The analysis of the data gathered across environments was performed as a series of experiments. The differences between hybrids and landraces and between Palomero Toluqueño and Cacahuacintle with Cónico and Chalqueño races explained most of the variability found among genotypes for the evaluated traits. The Ixtlahuaca landrace (control) showed a delayed flowering than Palomero Toluqueño and was earlier than other genotypes. Ixtlahuaca had lower stalk and root lodging and ear-rot percent than Palomero Toluqueño, Cacahuacintle, and Chalqueño; however, its stalk and root lodging percent was higher than that of hybrids of other races. Ixtlahuaca outyielded Palomero Toluqueño and Cacahuacintle, but was outyielded by Chalqueño, Cónico-Chalqueño hybrids, and hybrids of other races such as AS-722, Cóndor, and H-40. The genotype by-trait analysis indicated that Palomero Toluqueño was the earliest and lowest grain yielder race. Cacahuacintle was the most susceptible to stalk and root lodging and to ear-rot caused by Fusarium spp. Cónico and Chalqueño races were more resistant to stalk and root lodging and ear-rot, and outyielded Palomero Toluqueño and Cacahuacintle. As a group, the hybrids Cóndor, H-33, H-40, H-44, and H-90E showed high grain yield and low ear-rot percent. Ear-rot was positively correlated with stalk and root lodging and both traits were negatively correlated with grain yield.

Palabras llave : Fusarium moniliforme; Fusarium graminearum; Zea mays L.; genotype by trait analysis; highland maize races.