Breeding potential of maize landraces evaluated by their testcross performance

Abstract

Significant amounts of crop diversity, especially in out-crossing species like maize (Zea mays L.) is, are often distributed both between and within related groups of accessions. Thus, a detailed characterization and classification of gene bank accessions should be performed prior to use of the best of them for introgression programs to enlarge the genetic base of the elite germplasm pool. Based on performances per se, 40 landraces were chosen out of the wide pool of Western Balkan landraces, previously clustered into 11 homogenous groups. The objective of this study was to evaluate the heterotic pattern of landraces in testcrossing with three divergent elite testers L217, L73B013 and L255/75-5. According to the results of a two-year trial conducted at four locations, landraces 1267, 1346, 197, 1569, 1509 and 2036 expressed the best general combining abilities (GCA) for grain yield. Landraces 1960, 642, 2006, 1945, 1346, 1569, 1450, 1534, 1509 and 1665 performed well in crosses to L217, while landraces 1960, 773, 1798, 1665, 632, 877 and 1569 gave the best results in crosses to inbred tester L73B013. In crosses to inbred tester L255/75-5, the highest heterotic effects were expressed by landraces 467, 773, 1346, 1534, 2249 and 288. Particular attention is to be paid to landraces 1346, 1569 and 1509, having simultaneously high GCA and specific combining abilities (SCA). A certain number of landraces expressed heterosis with two inbred testers, indicating existence of a new unrelated heterotic pattern within the local germplasm pool evaluated.