Submitted to: Crop Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/11/2005
Publication Date: 3/1/2006
Citation: Williams, W.P., Windham, G.L. 2006. Registration of maize germplasm line Mp717. Crop Science. 46:1407-1408. Interpretive Summary: Aflatoxin is a toxin produced by the fungus Aspergillus flavus. The presence of this toxin in corn reduces the value of the grain and greatly restricts its marketability. Aflatoxin contamination is a major limitation to profitable corn production in the southern USA. Growing corn hybrids with genetic resistance to fungal infection and aflatoxin accumulation is considered to be the best way of reducing losses to aflatoxin contamination. To produce such hybrids, corn germplasm with resistance must be identified and developed. Mp717 was developed by several generations of breeding and selection for higher levels of resistance. It exhibits a level of resistance similar to that of the best aflatoxin-resistant lines now available. It also matures earlier than the other resistant lines, and early maturity is a desirable attribute. It combines well with other resistant lines to produce hybrids with high levels of resistance to aflatoxin contamination. Seed of Mp717 are available to plant breeders for use in their breeding programs. Its use in commercial breeding programs should increase the level of aflatoxin resistance in corn hybrids available to farmers.
Technical Abstract: Maize (Zea mays L.) germplasm line Mp717 was released by USDA-ARS and the Mississippi Agricultural and Forestry Experiment Station in July 2005 as a source of resistance to Aspergillus flavus infection and aflatoxin contamination. Mp717 was developed from a cross of MP420 and Tx601 by selfing for eight generations and selecting for resistance to aflatoxin contamination in the grain. Mp717 was evaluated for resistance to aflatoxin contamination in a series of experiments conducted from 2000 to 2004 at Mississippi State, MS. Ears were inoculated with an A. flavus spore suspension 7 to 14 d after silk emergence and aflatoxin content in the grain was determined in mature ears. Mp717 exhibited significantly greater resistance than its parent, Mp420, and levels of resistance similar to Mp313E and Mp715. Mean levels of aflatoxin contamination for the resistant germplasm lines Mp313E, Mp420, Mp715, and Mp717 were 145, 875, 280, and 189 ng g -1. Mean levels of contamination for susceptible lines GA209, Mp339, and SC212M were 4002, 2005, and 5580 ng g -1. In a diallel cross, Mp717 exhibited significant general combining ability for reduced aflatoxin contamination. Mp717 flowers approximately 7 d earlier than Mp313E and 14 d earlier than Mp715. Mp717 has yellow kernels, white cobs, and good husk coverage. Plants are approximately 1.3 m tall.