Heterotic patterns among French and Spanish maize populations

Abstract

The objective of this work was to identify heterotic patterns among maize (Zea mays L.) populations representing the variability of Southwestern Europe. Six Spanish and six French maize populations were crossed in a complete diallel without reciprocals. The average yield of hybrids and populations was 6.1 t ha-1; mid-parent heterosis for yield was 22.0%, ranging from 12.2% to 51.9%. The population Lazcano produced the hybrids with highest yield, followed by Tuy, Rastrojero and Millette du Lauragais (ML). The environment x population interaction was significant for yield, therefore each environment was analyzed separately in order to determine the best heterotic pattern for each environment. The heterotic patterns suggested were Tuy x Rastrojero (Pontevedra), Rastrojero x ML (Zaragoza), Bade x Millette Montagne Noire (Mauguio), and Tuy x Lazcano (Saint Martin de Hinx). The most promising early heterotic pattern was Bade x Esterre. The most promising combination across sites was Lazcano x ML with the highest yield (7.7 t ha-1) and a mean heterosis of 30.7%. The cluster analysis based on mid-parent heterosis showed three clusters, corresponding to the dry areas of Spain, northern Spain, and southern France. These clusters are consistent with previous knowledge based on history, isozymes, and RFLP. The potential heterotic patterns are dry Spain x humid Spain or dry Spain x south France, although within these groups there were also some favorable combinations.