Maize is a staple food in many of the SSA countries and is commonly grown by resource poor, small-scale farmers in rural areas.
It covers 25 million hectares in SSA that produce 38 million metric tons  but the average maize yield in the region is estimated at 1.4 tons per hectare, which is about 20%, 37% and 56% of the average maize yield in developed countries, Brazil and Philippines, respectively .
Identification of QTL with large phenotypic effects conserved across genetic backgrounds and environments is one of the prerequisites for crop improvement using marker assisted selection (MAS).
The objectives of this study were to identify meta-QTL (m QTL) for grain yield (GY) and anthesis silking interval (ASI) across 18 bi-parental maize populations evaluated in the same conditions across 2-4 managed water stressed and 3-4 well watered environments.
At least the 4 m QTL (m QTL2.2, m QTL6.1, m QTL7.5 and m QTL9.2) associated with GY under both water-stressed and well-watered environments and detected up to 6 populations may be considered for fine mapping and validation to confirm effects in different genetic backgrounds and pyramid them into new drought resistant breeding lines.
This is the first extensive report on meta-analysis of data from over 3100 individuals genotyped using the same SNP platform and evaluated in the same conditions across a wide range of managed water-stressed and well-watered environments. mays L.) is an important source of food and nutritional security for millions of people in the developing world, especially in sub-Saharan Africa (SSA) and Latin America .Several factors, including high frequency of drought stress, scarcity and high cost of irrigation, and farmers’ inability to obtain quality seeds and fertilizers, contribute to such low productivity in the region.Given the unpredictable nature of drought and climate variability over years, breeders must develop improved maize hybrids that are able to withstand drought stress without significant yield penalty under optimal rainfall conditions [3–5].The meta-analyses identified 68 m QTL (9 QTL specific to ASI, 15 specific to GY, and 44 for both GY and ASI).Mean phenotypic variance explained by each m QTL varied from 1.2 to 13.1% and the overall average was 6.5%.Each physical interval of the m QTL consisted of 5 to 926 candidate genes.Meta-analyses reduced the number of QTL by 68% and narrowed the confidence intervals up to 12-fold.Neither Bio One nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the Bio One website.Stress caused by early weed competition is known to delay the rate of maize development which may result in a decrease in kernel number.Using MABC, Ribaut and Ragot  introgressed 5 QTL associated with yield components and flowering in maize from a donor parent into a drought susceptible recurrent parent.The authors reported increased grain yield and reduced ASI under water-limited conditions.