Project Number: 1907-21000-034-22
Project Type: General Cooperative Agreement

Start Date: Oct 01, 2011
End Date: Mar 31, 2014

Objective:
A multidisciplinary team involving USDA, Embrapa, JIRCAS, IRRI and Moi University will work on the identification and characterization of genes associated with maize P efficiency (tolerance to low P). The objectives for this research project include: 1. Pup-1 candidate gene identification in maize 2. QTL/gene mapping for P use efficiency in maize 3. Inheritance studies on maize root architecture under high and low P 4. Validation of maize Pup-1 candidate genes and if necessary, novel P efficiency QTL (if maize Pup1 homologues are not functional in P efficiency)

Approach:
A multidisciplinary team involving USDA, Embrapa, JIRCAS, IRRI and Moi University will work on the identification and characterization of genes associated with maize P efficiency (tolerance to low P). Bioinformatics will be used to identify homologues of the rice Pup-1 (P uptake efficiency) gene in maize and a set of markers for these genes will be developed. An Embrapa inbred line panel that was developed for breeding for P efficiency be phenotyped in the field for this trait measured as grain yield under contrasting P conditions and in the greenhouse/lab for root architecture traits; also the Buckler association panel will be phenotyped for P efficiency and root architecture traits in the green house/lab at USDA-ARS. Finally, a maize RIL population from the cross of a highly P efficient tropical maize line (L3) with a P inefficient line (L22) will be phenotyped to identify QTLs for P acquisition, internal P efficiency and root architecture traits. Also, candidate genes for p efficiency will be mapped on the same RIL population, in order to verify the co-segregation of Pup-1 homologs with QTLs for different P-efficiency traits. Finally, association analysis using Embrapa’s elite inbred lines panel and the Buckler maize association panel will be carried out to validate candidate genes.