1/8 ISSN 0100-2945 http://dx.doi.org/10.1590/0100-29452017168 MORPHOLOGICAL TRAITS AS TOOL TO VERIFY GENETIC VARIABILITY OF INTERSPECIFIC DRAGON FRUIT HYBRIDS1 ADRIANA DE CASTRO CORREIA DA SILVA2, RAFAEL ROVERI SABIÃO3, FERNANDO MARCELO CHIAMOLERA3, DANIELA MOTA SEGANTINI4, ANTONIO BALDO GERALDO MARTINS5 ABSTRACT - With recent cultivation in Brazil, the dragon fruit still have lacks related to the selection of promising materials and there are not yet commercial varieties in the country. Therefore, manual pollination cross were held in 2010, between plants of H. undatus x H. polyrhizus and H. undatus x H. setaceus. Aiming evaluate the genetic diversity of the progenies for future use in breeding program, based on cladodes characteristics, six characters were assessed: length and diameter of stem, distance between areoles, arch height, number and size of spines/areole. From the Euclidean distance matrix analysis was constructed a dendrogram by the UPGMA method. There was great variability among hybrids, and eight of them have shown promise for use in breeding program. Index terms: genetic relationship, multivariate analysis, Hylocereus undatus, H. polyrhizus, H. setaceus. CARACTERIZAÇÃO MORFOLÓGICA PARA ESTUDO DA DIVERGÊNCIA GENÉTICA DE HÍBRIDOS INTERESPECÍFICOS DE PITAYA1 RESUMO-De cultivo recente no Brasil, a pitaya ainda carece de estudos relacionados à seleção de materiais promissores, não havendo, até o momento, nenhuma variedade comercial registrada no País. Assim, realizaram-se polinizações cruzadas entre plantas de Hylocereus undatus × H. polyrhizus e H. undatus × H. setaceus. Baseando-se em características do cladódio, avaliou-se a divergência genética das progênies, visando à utilização futura em programa de melhoramento genético. Foram avaliados seis caracteres: comprimento e diâmetro dos ramos, distância entre aréolas, altura das costilhas, número e tamanho dos espinhos por aréola. A análise de agrupamento pelo método UPGMA foi feita a partir da matriz de distância Euclidiana. Houve grande variabilidade entre os híbridos, e oito deles mostraram-se promissores para serem utilizados em programa de melhoramento genético. Termos para indexação: análise multivariada, pitaya-vermelha, diversidade genética, variabilidade genética. 1(Paper 170-15). Received June 29, 2015. Accepted April 12, 2016. 2Agr. Eng., Dr., Universidade Estadual de Mato Grosso do Sul, UEMS, Unidade Universitária de Aquidauana. Rod Aquidauana- Piraputanga, km 12, Aquidauana-MS, 79200-000, Brazil. E-mail: [email protected]; 3Agr. Eng., M. Sc., PhD students in Agronomy at Faculdade de Ciências Agrárias e Veterinárias, UNESP - Univ. Estadual Paulista, Jaboticabal Campus, Dept. of Plant Production, Jaboticabal-SP, 14884-900, Brazil. E-mail: [email protected]; chiamolera@ hotmail.com 4Agr. Eng., Dr., Faculdade de Ciências Agronômicas, UNESP - Univ. Estadual Paulista, Botucatu Campus , Dept. of Horticulture, 18610-307, Botucatu-SP, Brazil. E-mail: [email protected] 5Agr. Eng., Dr., Fruitculture Professor, Faculdade de Ciências Agrárias e Veterinárias, UNESP - Univ. Estadual Paulista, Campus de Jaboticabal, Dept. of Plant Production, Jaboticabal-SP, 14884-900, Brazil. E-mail: [email protected] Rev. Bras. Frutic., v. 39, n. 1: (e-168) DOI 10.1590/0100-2945 2017 168 Jaboticabal - SP 2 A. de C. C. da SILVA et al. INTRODUCTION morphological characters related to the stem in order to separate the more dissimilar, to be used as the basis Cultivated in Brazil just over a decade, the for breeding programs. pitaya still lacks in studies related to the selection of promising materials. There is, so far, no commercial MATERIAL AND METHODS variety registered in the country. The external and internal appearance of the fruits, mainly as to the The experiment was carried out in the coloring, is what differentiates the types of pitayas. Fruitculture Nursery of the Faculty of Agrarian and Four species are of commercial importance in Veterinary Sciences of Jaboticabal (FCAV / UNESP, the country, Hylocereus undatus, H. polyrhizus, 21º14’33”S and 48º17’02”W, 563m altitude). The H. setaceus (Sin.: Selenicereus setaceus) and H. evaluated progenies were obtained from interspecific megalanthus (Sin.: S. megalanthus). cross-pollination, carried out manually in 2010: In most orchards, the producers themselves H. undatus x H. polyrhizus (L2P17); H. undatus x multiply their material by cutting, which guarantees H. polyrhizus (L4P3); H. undatus x H. polyrhizus the uniformity of the orchard and the precocity of (L4P11); H. undatus x H. setaceus (L2P6); H. production. Thus, the orchards show practically no undatus x H. setaceus (L2P7). The denomination variability, which is ideal for marketing purposes, but in brackets refers to the location of the access in the undesirable in terms of plant genetic improvement. Germplasm Active Bank of the FCAV / UNESP (L: For variability induction, seed propagation may be line; P: plant). The hybrids were named according a resource to be exploited since the plants obtained to the access code of the pollen donor species, by sexual propagation may be similar to one of the number after the hyphen corresponding to the the parents, to both or none of them. The obtained accession number. Altogether, 45 progenies and six individuals (F1 generation) will have different parental (Table 1) were morphologically evaluated. characteristics, being possible, from these materials, The evaluated progenies were kept in a greenhouse, to select those with desired characteristics. Therefore, with 50% shading, cultivated in plastic pots of 11 researches aiming at the species improvement are of liters, in a substrate containing soil, sand and corral great value, since they can result in the selection of manure, in a proportion of 3: 1: 1. At the time of more vigorous and productive materials and fruits of the evaluation they were about 3 years old and, the better quality than those currently available. In the parents, 10 years. pitayas, because they have a narrow genetic base, The morphological characters studied were the accomplishment of interspecific hybridizations chosen based on the UPOV publication -International is facilitated (TEL-ZUR et al., 2004), allowing Union for the Protection of New Varieties of to join, from these controlled crosses, favorable Plants (2011), with some adaptations. A total of six characteristics of different species, being able to vegetative morphological characters related to the obtain new varieties with specific characteristics cladodes were recorded for each genotype, being: such as fruit quality. length and diameter of stem, distance between In order to characterize germplasm variability, areoles, arch height, number and size of the spines the use of molecular markers such as RAPD per areole. The measurements were taken from the (Random Amplified Polymorphic DNA) and ISSR secondary cladodes in the median portion of the (Inter Simple Sequence Repeats) have been widely stem, taking five measurements per cladodes, in used (JUNQUEIRA et al., 2010a; JUNQUEIRA three cladodes per plant (Figure 1). The spines were et al., 2010b; TAO et al., 2014) however it is collected from the same region, counting the number possible, through the description of morphological of spines per areole and measuring their size. These characteristics, to verify the variability of a set of characteristics were recorded for both parents and plants. Pitaya presents great ecotypic diversity, progenies. and species can be defined according to the For the study of the hybrids and parental characteristics of cladodes, flowers and fruits (ORTIZ genetic divergence from the characteristics related HERNÁNDEZ; CARRILLO SALAZAR, 2012). In to the cladodes, a genetic distance matrix was some plant species, the distinction between varieties calculated, using the Euclidean distance, obtained can be performed based on the morphological aspects by the following expression (CRUZ, 2006): (e01) of the plants, which allows identification when there are still no flowers and / or fruits (ANDRADE; MARTINS, 2007). So the objective of this study was to evaluate pitaya interspecific hybrids, through Rev. Bras. Frutic., v. 39, n. 1: (e-168) DOI 10.1590/0100-29452017 168 Jaboticabal - SP MORPHOLOGICAL TRAITS AS TOOL TO VERIFY GENETIC VARIABILITY... 3 where, undatus x H. polyrhizus (L4P11) and H. undatus x dii´: Euclidean distance between genotypes H. polyrhizus (L2P17), but no genotype was 100% i and i´; different from the other, even when comparing Yii´: Is the value obtained for the i-th genotype different species, which corroborates with the in relation to the j = th variable. observation of Tel-Zur et al. (2004) on the pitaya From this matrix, the clustering analysis was narrow genetic base. The most similar hybrid to the performed using the UPGMA method (Unweighted mother plant (H. undatus) was the L4P3-13 individual Pair Group Method Using Arithmetic Averages). (0.54). Evaluating wild and cultivated accessions of The adjustment between the genetic distances matrix the species H. undatus and H. polyrhizus Tao et al. and the generated dendrogram was calculated by the (2014) observed that the genetic distance ranged cophenetic correlation coefficient (r) (SOKAL and between 1.79 and 8.06, and the highest variation was ROHLF, 1962). The relative contribution of each obtained among cultivated accesses. cladodes related characteristic to the estimation In Brazil some researches realized by of genetic diversity was also studied by the Singh Junqueira et al. (2010a; 2010b) aim