Simultaneous selection for stem borer resistance and forage related traits in maize (Zea mays ssp mays L.) x teosinte (Zea mays ssp mexicana L.) derived populations

Maize spotted stalk borer (Chilo partellus Swinhoe Pyralidae) (MSSB) is a serious pest of the maize (Zea mays ssp. mays L) crop in Pakistan. This study was conducted to introgress resistance in maize against MSSB by exploring wild sources of resistance for the development of a resistant maize variety. To achieve this, teosinte ('PI566674') x maize ('Sargodha-2002') crosses were conducted and three populations (F-1, F-2 and F-3) were established. These populations were screened at various locations and in a contrasting artificial insect infestation experiment. Teosinte species 'PI566674', following screening, was shown to be highly resistant to MSSB and had the ability to produce a high biomass (5 times higher than susceptible genotypes) under high temperatures (36-40 degrees C). The biomass of the F-1 hybrid, which was highly susceptible to MSSB, was significantly reduced (P <= 0.05) following infestation by MSSB in all experiments. The introgression from teosinte for genes conferring resistance to MSSB was screened in segregating F-2 and F-3 generations. Despite a susceptible F-1 population, F-2 was resistant to MSSB. Twenty new recombinant plants with resistance to MSSB and a high leaf soluble solid (16 degrees Brix) content were identified. They were selected to grow the F-3 population. Mean values of F-3 progenies showed similar resistance to the F-2 population but a high percentage (60%) of resistant plants was recovered. (C) 2013 Elsevier Ltd. All rights reserved.