Genetic Analysis of Kernel Water Relation Traits in Maize.

The relationship between dry matter accumulation and water content in the kernel, the kernel water relation, is indicative of the final kernel weight and maximum kernel volume, both of which are closely tied to grain yield.  We are determining if rates of accumulation of moisture and dry-matter content in maize kernels can be associated with segregating genomic regions in a family of testcrossed RILs.  Canonical physiological models indicate that dry-matter accumulation in the maize kernel begins after a lag phase and continues until the kernel reaches maturity.  These same models suggest that accumulation is not linear but rather follows a sigmoid curve over time.  Canonical models of moisture content are based on a quadratic relationship with time across all phases of kernel growth and maturation.  (Bewley and Black, 1994) Our approach is to first determine the repeatability of estimated parameters in the models of dry matter accumulation and moisture content.  If the estimates of these parameters are repeatable, variability in the estimated parameters among a family of testcrossed RILs will be used to map QTL.