An official website of the United States government.
<ul> <LI>Develop lines from tropical germplasm and from crosses between adapted, 100%-tropical lines and US material.<LI> Evaluate semi-exotic GEM families and derive inbred lines from better ones. <LI>Convert late-maturing NC lines releases to earlier maturity. Incorporate resistance to gray leaf spot into adapted materials. <LI>Gain increased understanding of gametophyte factors found in tropical maize.
Non-Technical Summary: The US maize germplasm base is dangerously narrow. This project incorporates new sources of elite tropical germplasm into useful, adapted lines. <P> Approach: Breeding materials will be obtained from crosses with 4th generation lines derived from a base population of tropical hybrids. Within less-adapted pedigrees, sib-mating will be conducted prior to selfing. Ear-to-row selection will include standability, disease resistance, low plant and ear height, and low ear moisture. The GEM project will continue collaboration with private companies to test 50%-exotic populations. F1S1, F2S1, or F2S2 families are evaluated in yield trials using elite testers. Selfing and testcrossing is continued in better-performing GEM families. Continue conversion of later-maturity NC lines to earlier flowering by backcrossing to early, elite sources. Resistance to gray leaf spot will be incorporated into standard backcrossing and line development efforts. Individual plant selection will be used to speed dry-down.