Diallel Analysis of Diverse Maize Germplasm Lines for Agronomic Characteristics and Resistance to Aflatoxin Accumulation.

In this study, diverse, novel maize germplasm from the Genetic Enhancement of Maize (GEM) project was evaluated to determine the combining ability and inheritance of maturity, plant and ear height, and yield with respect to aflatoxin accumulation in hybrid combinations.  Nine GEM germplasm lines and six lines known to be resistant or susceptible to aflatoxin accumulation were selected as parents of a diallel cross that was evaluated over two years at Mississippi State, MS and one year at College Station, TX.  Resistant lines on average are taller and later maturing, with positive and significant GCA effects across environments, but were frequently present as parents in the hybrid combinations with the lowest aflatoxin values.  Of the GEM lines evaluated, NEI9008 generated highly significant positive GCA effects for yield.  GEM lines GEMS-0074 and GEMS-0002 exhibited significant negative GCA effects for plant height and maturity resulting in shorter (11 to 24 mm) and earlier (2.7 to 4.1 days) hybrids.  GEM lines  contributing to significantly shorter and earlier hybrids may be used in a breeding program to improve the agronomic characteristics of known resistant lines while also potentially contributing new sources of resistance to aflatoxin accumulation. These results demonstrate the GEM Project is a useful and untapped source of diverse germplasm for resistance to aflatoxin accumulation and improved agronomic characteristics.

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