Selection strategy for developing maize inbred lines with drought and disease resistance in Uganda

Breeding for host plant resistance along with performance traits requires the use of an effective breeding method and selection strategy. Such a selection strategy and related indices should contribute to reducing the time required for breeding, and saving resources for further development and testing. This study of a maize (Zea mays) population identified efficient selection indices and a selection strategy for maize lines that combines selecting for traits of primary interest such as anthesis-silking interval (as a proxy for drought tolerance), and resistance to both Turcicum leaf blight (TLB) and maize streak virus (MSV) with other characteristics that directly and indirectly influence grain yield. Testcrosses were generated during the short rainy season of 2011 (August – December) at Kasese, with single cross (SC) testers from heterotic groups A and B used as males, planted in multiple rows, and pollen-bulked. F3 lines were used as females, and planted ear-to-row in single-row plots. These crosses were then tested in three locations (Serere, Namulonge and Bulindi), in order to evaluate the performance of families in their early-segregating generations. Data was collected on a plot basis for: MSV, TLB (using rating scale 1 to 5), and ASI. The anthesissilking-interval (ASI) was calculated from the difference between the silking and anthesis dates (ASI = SD – AD). Analysis of variance for single environments was based on lattice design using the linear mixed model procedure GENSTAT 14th edition.