Discrimination of varietal groups and hybrids of coffea canephora species using multivariate analysis

Abstract

Coffee growing is one of the most important agricultural activities in the world market. Coffea canephora is one of the most commercially relevant species, which can be divided into the varietal groups Conilon and Robusta. These varietal groups have complementary agronomic interests. Therefore, hybrids are obtained through crosses between these groups. Given the difficulty in differentiating the two varietal groups of genotypes in the field, the correct discrimination is essential for the definition of crosses in breeding programs. In this context, the present work aimed to apply a discriminant analysis (DA) to define functions to differentiate between varietal groups and hybrids of C. canephora, and identify the most relevant phenotypic traits in these functions. Data from 165 genotypes from the Instituto Capixaba de Pesquisa, Assistência Técnica e Extensão Rural e do Centro Agronómico Tropical de Investigación y Enseñanza were used to measure different plant traits. It was applied the quadratic DA with the best performance for genotype discrimination, with an average apparent error rate of 0.0364. Cercosporiose incidence, rust incidence, vegetative vigor, plant height and diameter of the canopy projection were the most important traits in the varietal groups' discrimination.