Resumen

MALACARNE, María F.  y  SAN VICENTE G, Félix M.. PATRONES HETERÓTICOS DE LÍNEAS TROPICALES BLANCAS DE MAÍZ. Agronomía Trop. [online]. 2003, vol.53, n.4, pp.32-40. ISSN 0002-192X.

The objectives of this study were to determine the heterotie pattems and combining ability of white tropical maize, Zea mays L., inbred lines and to identify superior single cross hybrids. Forty-two lines with different leveis of inbreeding (S₄-S₁₄) were crossed to three testers. One hundred twenty six testerosses and four commercial checks were evaluated at four locations (Maracay, Agua Blanca, El Socorro and Las Guacamayas) in Venezuela during 1999. Data were collected on silking date, plant height, stalk lodging and grain yield. Average yield across locations was 6,55 t ha-¹. Six testcrosses yielded equal or more than the best check. General combining abílity (GCA) effeets among lines were highly significant (P£0,01) for all traits; while GCA effects among testers were only significant for silking date and plant height. Specific combining ability (SCA) effeets were not significant suggésting that grain yield is mostly controlled by additive gene action in this set of lines. Twenty lines had significant GCA effects for yield. Based on GCA and actual yield, two testers were selected to classify the lines in two contrasting groups. According to the SCA effects of the lines with two selected testers, 87% of the genetie material was elassified in two heterotic groups ("A" y "B"), which could be used as source gernplasm in hybrid development programs in Venezuela.

Palabras clave : Maize; Zea mays L; heterotic pattems; tropical germplasm; combining ability.