Phenotypic Screening and Association Mapping of a Peanut Germplasm Collection for Tolerance to Water Deficit Stress

The U.S. peanut minicore collection was screened over two years at two locations in Texas for response to water deficit stress.  The collection was also been evaluated in Burkina Faso at two locations over two years, with differences in rainfall between the two locations.  Field measurements were taken at biweekly intervals in Texas during mid-season drought, and significant differences were found among accessions for SPAD chlorophyll, flowering, paraheliotropism, and canopy temperature; differences in yield were also noted.  In Burkina Faso, stress and wilting ratings were taken, and significant differences were found, as well as for yield.  Association mapping using SSR markers identified markers for traits over multiple environments.  Some markers were associated with multiple traits, suggesting genetic control could involve pathways that govern more than one response.  Identification of novel sources of drought tolerance with different physiological responses, and markers for selection, could lead to improved cultivars.