Harnessing available genetic variation using the maize Allelic Diversity Platform at Syngenta

Breeders have exploited the genetic variation in maize to develop high yielding modern maize hybrids.  During this process a significant number of novel alleles were left behind. This untapped genetic variation present in wild relatives and land races may be useful for developing superior maize cultivars.  However, screening for useful novel alleles from this resource and introgression of such alleles into elite lines is time consuming. It is well documented that the allelic effects are over-estimated in QTL mapping context if the mapping population size is under 1000 individuals (Beavis effect). Also, the effect of novel superior alleles might be masked due to background interactions.  In order to evaluate and utilize the available genetic variation, Syngenta has developed a Maize Allelic Diversity (AD) Platform.  To identify the superior alleles, comparison of an allele series at a locus should be done in a uniform genetic background.  To accomplish this, Syngenta has developed two NIL panels.  In the first, a set of 134 lines comprising of diverse inbreds and land races were selected as donors, and two elite inbred lines (one stiff stalk and one non-stiff stalk) were used as recurrent parents.  The genomic regions of the donor lines were introgressed into recurrent parents by backcrossing for five generations.  The average introgression size ranges from 10-15 cM in size. In a second NIL panel, NAM founder lines were introgressed into B73.  The B73 NIL’s set was made available for public research by Syngenta through CIMMYT.  Solexa sequencing information along with metabolite profiling data is available for all the donors and NAM founder lines. This information is utilized for linking genes to specific metabolites and for marker development. Syngenta has been using the diversity platform to broaden their germplasm base in  a variety of different ways : i) for faster introgression of favorable alleles into elite lines, ii) for fine-mapping and cloning quantitative trait loci, and iii) for moving superior alleles from tropical germplasm to temperate lines.  Syngenta is looking for partners to establish trait collaborations where the AD collection and associated genomics resources are used to accelerate trait knowledge understanding in maize.