COMBINATORY FITNESS OF TROPICAL AND SUBTROPICAL CORN IN THE REGION OF LOW WARRIOR TRANSITION

Abstract

Five tropical and five subtropical varieties and their crosses in F₁ and F₂ were evaluated in six locations under rainfall conditions during 1981; a triple lattice 8 x 8 under a Genetic Design ll was used. General and Specific Combining Ability (GCA, SCA), inbreeding depression (ID) and heterosis were evaluated. Only two tropical and two subtropical varieties showed a positive GCA and 12 varietal
hybrids showed a positive SCA with three of them outstanding; the average ID value was 5.21 and the highest 17.84%; the average heterosis over the best parental variety was of 7.36% and the highest was 16.04%. Amajor contributionof the tropical over the subtropical maize was observed. The analysis of the stabil ity parameters showed that the parental variety VS-521 and its crosses were the most stable; in addition a clasification of the locations for numerical taxonomy was perfomed, and only two of them were consistently congregated.