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Near-Isogenic Line Allelic Series (NILAS)

A goal of this project is to deepen our understanding of genetic factors limiting access and use of genetic variability harbored by tropical germplasm for global maize improvement. We are producing a new germplasm resource for research and breeding. NILAS are collections of inbred lines differing at a single specific locus for a range of functional alleles. Using marker-assisted selection, we are producing NILAS for a set of genomic loci where there is overwhelming evidence of their role in photoperiodism.

Zea mays photoperiod QTL (ZmPRQTL) have been precisely mapped in a study using the 5k RIL nested association mapping population of maize (Hung et al. 2012). The QTL support intervals from this study are being used to guide marker-assisted development of the NILAS. Four ZmPRQTL are being separately introgressed from seven donor parent (DP) lines into two different recurrent parent (RP) lines. For each QTL x DP x RP combination, 12 separate introgressions are being produced, one containing the full interval and 11 representing a tiling path across the target region. Various NILAS contrasts will be used to test hypotheses on adaptation, selection, and linkage drag.