Phenotypical Diversity of Opuntia Spp. Accessed by Morphological and Bromatological Descriptors

The cactus pear (Opuntia spp.) belongs to the cactaceae family, composed of 130 genera and 2,000 species. Opuntia ficus-indica L. (Mill.) is the most cultivated species in the world. The Northeast Region is the main producer of prickly pear in Brazil. The cactus pear is used as forage for cattle in Brazil. The knowledge of genetic diversity is essential to obtain germplasm information and release this to breeding programs. The objective of this work was to evaluate the genetic diversity of 120 accessions of 12 species of the genus Opuntia and belonged to the Active Germplasm Bank (BAG) of EMPAER mantained at Fazenda Pendência, Soledade city, Paraíba State, Brazil. To assess this variability 15 morphological (four qualitative and eleven quantitative) were evaluated. Beside this ten bromatological characters were analysed. The obatained data were subjected to analysis of variance and multiple range test (p≤0.05). The broad-sense heritability, phenotypic and genotypic variances and correlations were estimated. The accesssion were grouped by Tocher Method based on the Mahalanobis distance and by the UPGMA method. The relative contribution of characters to diversity was estimated using Sing method (1981). The methods indicated the existence of genetic variability among the 120 evaluated accessions. The heritability of morphological traits were higher than 70% except for plant height. High heritability estimates increase the selection efficiency in a breeding program. The accessions 44 (O. strica), 109 (O. undulata), 7 and 13 (O. ficus-indica), 75 (O. megacantha), 104 and 116 (O. cochenillifera) presented the best forage performance. Those accessions should be used as parents in cactus pear breeding programs.