Genetic divergence among accessions of melon from traditional agriculture of the Brazilian Northeast

Abstract

ABSTRACT. The genetic divergence of 38 melon accessions from traditional agriculture of the Brazilian Northeast and three commercial hybrids were evaluated using fruit descriptors and microsatellite markers. The melon germplasm belongs to the botanic varieties cantalupensis (19), momordica (7), conomon (4), and inodorus (3), and to eight genotypes that were identified only at the species level. The fruit descriptors evaluated were: number of fruits per plant (NPF), fruit mass (FM; kg), fruit longitudinal diameter (LD; cm), fruit transversal diameter (TD; cm), shape index based on the LD/TD ratio, flesh pulp thickness, cavity thickness (CT; cm), firmness fruit pulp (N), and soluble solids (SS; °Brix). The results showed high variability for all Genetic diversity of Cucumis melo from Brazilian Northeast descriptors, especially for NPF, LD, and FM. The grouping analysis based on fruit descriptors produced eight groups without taxonomic criteria. The LD (22.52%), NPF (19.70%), CT (16.13%), and SS (9.57%) characteristics were the descriptors that contributed the most to genotype dissimilarity. The 17 simple sequence repeat polymorphic markers amplified 41 alleles with an average of 2.41 alleles and three genotypes per locus. Some markers presented a high frequency for the main allele. The genetic diversity ranged from 0.07 to 0.60, the observed heterozygosity had very low values, and the mean polymorphism information content was 0.32. Molecular genetic similarity analyses clustered the accessions in 13 groups, also not following taxonomic ranks. There was no association between morphoagronomic and molecular groupings. In conclusion, there was great variability among the accessions and among and within botanic groups.

Diversity and flower-visiting rates of bee species as potential pollinators of melon (Cucumis melo L.) in the Brazilian Cerrado

“…In the present study, although the melon cultivars were not initially developed for cultivation in the Cerrado regions, all the melon cultivars (except the 'Hibrix' cultivar) showed feasibility for production under Cerrado conditions. The cultivars produced fruit of marketable size, and their estimated yields were over 25 tons/ha, which were in the range registered in other Brazilian regions (Aragão et al, 2013;Nunes et al, 2006).…”

Botanical Identification and Genetic Diversity in Melons From Family Farming in the State of Maranhão

“…Using this system, although working with the same germplasm, the groups identified by Torres Filho et al (2009) cannot be compared with the data of the present work. Similarly, Aragão et al (2013) studied the genetic diversity of accessions previously characterized by Torres Filho et al (2009), but adopted the classification of Robinson and Decker-Walters (1997), which is also very different from that used by Pitrat, Hanelt and Hammer (2000), since it considers the existence of only six varieties. The authors also observed that there was no association between morphological and molecular clusters (ARAGÃO et al, 2013).…”

“…Similarly, Aragão et al (2013) studied the genetic diversity of accessions previously characterized by Torres Filho et al (2009), but adopted the classification of Robinson and Decker-Walters (1997), which is also very different from that used by Pitrat, Hanelt and Hammer (2000), since it considers the existence of only six varieties. The authors also observed that there was no association between morphological and molecular clusters (ARAGÃO et al, 2013). Although the information available in the Brazilian literature cannot be compared with the results achieved in this study, they invariably corroborate the existence of large variability within and among melon accessions from family farming in the state of Maranhão.…”

“…More recently, a study investigated the diversity of melons collected from family farming in Northeast Brazil, based on morphological and molecular characters (DANTAS et al, 2015). However, the two previous works used classifications that did not consider melon subspecies (ARAGÃO et al, 2013;TORRES FILHO et al, 2009), while the last work (DANTAS et al, 2015) used the classification by Pitrat, Hanelt and Hammer (2000), which takes these subspecies into account (agrestis, with five varieties, and melo, with eleven varieties). Nonetheless, Dantas et al (2015) only used six accessions from family farming in the state of Maranhão.…”

“…Studies by Aragão et al (2013) and Torres Filho et al (2009) highlight the existence of a great genetic diversity in melon accessions from family farming in the state of Maranhão. More recently, a study investigated the diversity of melons collected from family farming in Northeast Brazil, based on morphological and molecular characters (DANTAS et al, 2015).…”