Genetic diversity for agronomic and bromatological traits in forage cactus

Abstract

This work aimed to estimate the genetic diversity in accessions of Opuntia ficus-indica collected in 13 regions of the semiarid region of Bahia. A total of 65 accessions were evaluated in a randomized complete block design, with three replications, at the Rio Seco experimental station belonging to the State University of Feira de Santana, Amélia Rodrigues-BA. Characterization of the accessions was made through the evaluation of 17 descriptors, namely 11 agronomic and six bromatological. The average Euclidean distance was used to estimate the genetic diversity among accessions. The shortest distances were obtained for accessions from the same collection site while the largest were observed in accessions 54 and 62 (10.32 DE) and 63 and 3 (10.22 DE). The analysis of canonical variables indicated cladodes total number (CTN), plant width (PW), CL, plant height (PH), ether extract (EE), and dry weight (DW) for discard as they presented the lowest contribution of the data set variation. Principal component analysis and K-means method were used to establish the clusters, and the formation of four groups was indicated. The first two principal components captured 52.5% of the total variation present in accessions. The descriptors with the greatest contribution to the variation observed in O. ficus-indica were total cladode photosynthetic area (TCPA), cladode area (CA), and cladodes width (CW). There is divergence between cactus forage accessions collected in the semiarid region of Bahia. This information will allow the use of these materials for the formation of segregating populations in the genetic improvement program of the State University of Feira de Santana. The accessions of groups III and IV should be explored by the forage cactus breeding program, as they presented greater productive potential.

Keywords

• cactus forage; genetic improvement; multivariate analysis.