HETEROSIS AND ENDOSPERM TEXTURE IN CROSSES INVOLVING MAIZE LANDRACES OF THE ST-LAWRENCE GREAT-LAKES REGION OF NORTH-AMERICA

The native peoples of the St. Lawrence-Great Lakes region of North Ame rica grow and protect their own landrace varieties of white floury mai ze (Zen mays, L.). They use the grain as food. The kernel and ear char acteristics of the landraces are valued by the native peoples. The Ind ian Agricultural Program of Ontario (IAPO) has collected 35 maize acce ssions from native farmers in Ontario and New York State and has used some of them in a pilot project to establish a snack food industry usi ng traditional native cooking techniques to process indigenous maize p roduced by native farmers. The floury endosperm texture of the IAPO ma ize is suitable for processing, but the landraces have poor standabili ty and yield in comparison with commercial maize hybrids. Improvements in agronomic performance might be obtained by using variety crosses a mong the landraces, and/or by crossing of the landraces with other mai ze germplasm. In this study, several crosses among IAPO landraces and several crosses between IAPO landraces and unrelated white flint inbre ds were evaluated in field experiments. Significant heterosis over the mid-par ent value was observed in crosses involving a low-yielding la ndrace from one reserve of origin with higher yielding landraces from another reserve. However, these variety crosses did not yield signific antly more than the best yielding landrace. Crosses between landraces and white flint inbreds yielded more than either parent. At one evalua tion site, they yielded significantly more than the best yielding land race. As anticipated, the landrace x inbred crosses lacked some of the characteristic ear traits of the IAPO germplasm. Six landraces were a lso crossed with inbred testers homozygous for the floury endosperm1 ( fl1) allele. None of the F-2 kernels from these testcrosses mere vitre ous, indicating that the IAPO material probably carries the fl1 allele .