Demand-Driven Technologies for Sustainable Maize ... - IITA

43Genetic analysis of drought tolerancein maize inbred lines: preliminary resultsS.K. Meseka 1 , A. Menkir 2 , and A.S. Ibrahim 31Agricultural Research Corporation, Wad Medani, Sudan.2International Institute of Tropical Agriculture, (IITA), Ibadan, Nigeria3Faculty of Agricultural Sciences, University of Gezira, Wad Medani, SudanAbstractDrought stress causes signifi cant yield reduction in maize (Zea maysL) grown in sub-Saharan Africa (SSA). An understanding of theinheritance of drought tolerance would be useful in developing droughttolerant hybrids. The objectives of this study were to determine (i) theeffects of the level of drought tolerance in parental inbred lines onthe performance of their hybrids, (ii) mode of inheritance of droughttolerance in inbred lines selected for contrasting responses to drought,and (iii) relationship between per se performance of the parental linesand their hybrids. A Design II mating scheme was used to produce96 single-cross hybrids from 24 inbred lines. The parental lines and F 1hybrids were evaluated in separate trials laid out side by side at Ikenne,Nigeria in 2002. Both general (GCA) and specifi c (SCA) combiningabilities were signifi cant (P < 0.01), with GCA accounting for >50%of total variation for all traits except ears per plant under well-wateredconditions. These results indicated that additive genetic effects largelyinfl uenced grain yield and other traits of the hybrids when evaluatedunder water stress. Most of the crosses with at least one tolerant parentproduced tolerant hybrids, whereas most of the crosses involving twosusceptible lines produced susceptible hybrids. Mid-parent values ofinbred lines per se were useful predictors of hybrid performance forall traits except ear aspect scores. Inbred lines KU1409, 1824, 9006,4001, POP10, and (TZI501xKU1414x501) could be used as parentsfor developing drought tolerant maize hybrids. Results of this study ledto the conclusion that yield improvement in drought tolerant maize isassociated with the level of drought tolerance in parental lines.RésuméLa sécheresse est un stress qui cause une réduction signifi cative derendement chez le maïs (Zea mays L) en Afrique sub-Saharienne(ASS). La compréhension du mode de transmission de la toléranceà la sécheresse serait utile pour la création d’hybrides tolérants à lasécheresse. Les objectifs de cette étude étaient de déterminer (i) leseffets du niveau de la tolérance à la sécheresse des lignées parentales