TY  - PRO
AU  - Preciado Ortiz,R.E.
AU  - Erazo Barradas,M.
AU  - Gomez M.N.O.
AU  - Sierra Macias,M.
AU  - Torreón Ibarra,A.D.
ED  - Centro Internacional de Mejoramiento de Maiz y Trigo (CIMMYT), Mexico DF (Mexico)
ED  - Arnel R. Hallauer International Symposium on Plant Breeding
TI  - Use of the heterotic pattern concept to group inbread lines from different sources
U1  - 631.53 
PY  - 2003///
CY  - Mexico, DF (Mexico)
PB  - CIMMYT
KW  - Crossbreeding
KW  - Germplasm
KW  - AGROVOC
KW  - Inbred lines
KW  - Performance
KW  - Subtropical zones
KW  - Hybrids
KW  - Plant breeding
N2  - A key factor in most applied breeding programs is the establishment of a heterotic pattem (HP) among varieties for selecting inbred lines as potential seed stock in hybrids. Lines obtained from respective HP tend to complement one another in maximizing hybrid performance. HPs provide a logical choice of testers based on origin of lines. Also breeders can take advantage of knowledge about pedigree origin and relations among lines by evaluating experimental crosses between lines derived from identified HPs. After HPs have been established, breeding efforts are planned to enhance and optimize the selected HP . The selected HP has a strong impact on breeding materials chosen for selection. Reid Yellow Dent (RYD) and Lancaster Sure Crop (LSC) represent a well-known worldwide HP .Most public and private maize breeding programs are based on this HP for temperate regions and the use of an alternate HP for them is not practical because most applied programs are heavily involved with line recycling (Hallauer and Miranda 1988). For lowland tropical regions, Wellhausen (1978) suggested using the existing HP between flint and dent complexes. Nevertheless, because a broad genetic variation is involved in those sources, tropical and subtropical breeding projects should define their own HP to group their germplasm involved in hybrid development. Efforts to classify germplasm into HPs at INIF AP was initiated in 1987 for tropical lowland, and in 1993 for subtropical regions. The objective of this poster is to present results and advances of these efforts
ER  -