A Hierarchical, Open-Ended Breeding System, Hope, was initiated in the mid-1970s with the objective of developing a very broad-based breeding source for elite genetically unique inbred lines for the short-season corn growing areas of Canada and the Northern U.S. The hope breeding system, as initially designed, consisted of a hierarchy of 4 gene pools based on agronomic performance, i.e., low, intermediate high and elite performance levels. Each performance level had an "A" gene pool and a "B" gene pool, based on heterotic pattern. Thus hope consisted of 8 gene pools arranged in two hierarchical sets of 4 gene pools each. Increasingly stringent selection procedures are employed at each level for the hierarchy, but procedures have changed based on periodic evaluation of the system. Originally, mass selection was used in the low level gene pools, modified ear-to-row at the intermediate and high levels with a higher selection intensity at the high level, and reciprocal recurrent selection in the elite level gene pools. After 9 years (in 1986), half-sib family selection replaced mer at the intermediate level and S2 per se replaced mer at the high level. Currently, hope is undergoing a significant revision, so that only three levels (low, high, elite) are used, and " A " and "B" sets are maintained only at the elite level; thus, the newest version of hope will consist of only 4 gene pools. Mass selection continues to be used at the low level, S2 per se at the high level but reciprocal full sub will be used in the elite level populations, since its inception, about 1,000 introductions have been added to hope. RAPD analyses show that hope is very divergent from commercial hybrids. Two inbreds with hope germplasm were released in 1997.

English

0208|AGRIS 0201|AL-Maize Program|R01PROCE

Juan Carlos Mendieta

CIMMYT Publications Collection