GENOTYPIC DIVERGENCE AMONG SUNFLOWER POPULATIONS

Abstract

Genotypic divergence, among ten sunflower populations, was investigated, using the Mahalanobis’ D² statistic analysis and canonic variables to identify more similar and/or divergent groups, and, thus, better direct crossings in breeding programs. Four experiments were carried out in two seasons (June/July and February), in two localities (Goiânia and Goianésia, Goiás State, Brazil), in 1995 and 1996. A randomized complete block design was used, with ten treatments and four replications. Variance analysis showed great genotypic variability among the four populations, for all traits assessed. The genotypic divergence analysis, dendrograms based on Mahalanobis’ distance, and graphs supplied by the canonic variable scores showed that the populations grouped similarly and according to their regions of origin, for most cases. When the two genotypic divergence estimation methods were compared, it was concluded that both led to similar clustering results.

KEY-WORDS: Helianthus annuus L.; clusters; methods of genotypic divergence estimation; Mahalanobis.