ABSTRACT.


Carol Müller T.1, René Cortázar S.2, Patricio C. Parodi3 y Pablo Alvarado V.4
 

Six spring wheat (Triticum aestivum L.) genotypes were crossed in a diallel system. The F1 generation was evaluated for heterosis heterobeltiosis, combining ability, and gene action, as experessed in the following characters: a) grain yield; b) number of spikes per plant; c) number of kernels per spike, and d) kernel weight.
The average heterosis and heterbeltiosis value for grain yield in the F1 generatin was 21,46 and 6,52%, respectively, ranking from 3,81 to 44,62% and from - 14,66 to 33,96%. Griffing´s combining ability analysis, method 4, model 1, indicated that a large portion of the total genetic variance observed for all characters was due to general combining ability effects, and was consequently controlled by additive gene action. Jinks and Hayman´s graphic analysis demonstrated full dominance for all characters except kernels per spike that showed overdominance.
Apparently, there were no genetic barriers that could preclude an optimum combination of characters among the six genotypes involved in the study.

Keywords:
1Ing. Agr. Dirección actual: Dicksons of Howlmark, Country Down, Northern Ireland.
2Ing. Agr. Ph. d., Jefe Proyecto Cereales, Instituto de Investigaciones Agropecuarias, Casilla 5427, Santiago, Chile.
3Ing. Agr. Ph. D., Proyecto Cereales, Instituto de Investigaciones Agropecuarias, Casilla 5427, Santiago, Chile.
4Ing. Agr. M. S., Profesor Ayudante de las Cátedras de Genética y de Mejoramiento de Plantas, Facultad de Agronomía, Universidad de Chile, Casilla 1004, Santiago, Chile.