Abstract

The corn-breeding project of IDIAP evaluated 96
corn cultivars in 132 localities, during 1989-2000. The
highest yielding genotypes have been recommended to the
growers. Nevertheless, to continue improving the evaluation
system of new cultivars, it is necessary to determine their
confidence degree in relation to the regional cultivars. The
present study aimed to estimate the stability of the most sown
hybrids in the country by determining the performance,
normalised over zero (RNi) of the superior cultivars. The
confidence of performance was determined for the hybrids:
3018, 3031, HS-8, P-8916, P-94922, P-9490 and X-1358K;
compared to the hybrid X-304C. The evaluated hybrids were
classified in three categories: Genotypes with high confidence
(HS-8, P-9490 y X-1358K; 0.8= RNi<0.9), medium
confidence (3018, 3031, P-9422; 0.6 = RNi<0.8) and low
confidence (P-8916; 0.5=RNi<0.6). The values RNi for each
genotype represent the probability that a genotype exceeds
the mean level of production of the reference hybrid (X-
304C), RNi of 0.8 means that the performance of the new
hybrids was superior in 8 of 10 localities. Additionally, it was
verified that the confidence is a measure closely related to
parameters of stability based on a regression model. This
study stated that hybrids with superior capabilities of
production and adaptation to diverse ecological zones through
the years were HS-8, P-9490 and X-1358K.