RESEARCH ARTICLE Phenotypic and molecular characterization of sweet sorghum accessions for bioenergy production Michele Jorge da Silva 1 , Maria Marta Pastina 2 , Vander Fillipe de Souza 3 , Robert Eugene Schaffert 2 , Pedro Crescêncio Souza Carneiro 1 , Roberto Willians Noda 2 , Jose´ Eusta´ quio de Souza Carneiro 4 , Cynthia Maria Borges Damasceno 2 , Rafael Augusto da Costa Parrella 2 * 1 Departamento de Biologia Geral, Universidade Federal de Vic¸ osa, Vic¸ osa, Minas Gerais, Brasil, 2 Embrapa Milho e Sorgo, Sete Lagoas, Minas Gerais, Brasil, 3 Departamento de Engenharia de Biossistemas, Universidade Federal de São João del-Rei, São João del-Rei, Minas Gerais, Brasil, 4 Departamento de Fitotecnia, Universidade Federal de Vic¸ osa, Vic¸ osa, Minas Gerais, Brasil * rafael.parrella@embrapa.br Abstract Sweet sorghum [Sorghum bicolor (L.) Moench] is a type of cultivated sorghum characterized by the accumulation of high levels of sugar in the stems and high biomass accumulation, making this crop an important feedstock for bioenergy production. Sweet sorghum breeding programs that focus on bioenergy have two main goals: to improve quantity and quality of sugars in the juicy stem and to increase fresh biomass productivity. Genetic diversity studies are very important for the success of a breeding program, especially in the early stages, where understanding the genetic relationship between accessions is essential to identify superior parents for the development of improved breeding lines. The objectives of this study were: to perform phenotypic and molecular characterization of 100 sweet sorghum accessions from the germplasm bank of the Embrapa Maize and Sorghum breeding pro- gram; to examine the relationship between the phenotypic and the molecular diversity matrices; and to infer about the population structure in the sweet sorghum accessions. Mor- phological and agro-industrial traits related to sugar and biomass production were used for phenotypic characterization, and single nucleotide polymorphisms (SNPs) were used for molecular diversity analysis. Both phenotypic and molecular characterizations revealed the existence of considerable genetic diversity among the 100 sweet sorghum accessions. The correlation between the phenotypic and the molecular diversity matrices was low (0.35), which is in agreement with the inconsistencies observed between the clusters formed by the phenotypic and the molecular diversity analyses. Furthermore, the clusters obtained by the molecular diversity analysis were more consistent with the genealogy and the historic back- ground of the sweet sorghum accessions than the clusters obtained through the phenotypic diversity analysis. The low correlation observed between the molecular and the phenotypic diversity matrices highlights the complementarity between the molecular and the phenotypic characterization to assist a breeding program. PLOS ONE | https://doi.org/10.1371/journal.pone.0183504 August 17, 2017 1 / 19 a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 OPEN ACCESS Citation: da Silva MJ, Pastina MM, de Souza VF, Schaffert RE, Carneiro PCS, Noda RW, et al. (2017) Phenotypic and molecular characterization of sweet sorghum accessions for bioenergy production. PLoS ONE 12(8): e0183504. https://doi.org/ 10.1371/journal.pone.0183504 Editor: Jean-Marc Lacape, CIRAD, FRANCE Received: March 10, 2017 Accepted: August 4, 2017 Published: August 17, 2017 Copyright: © 2017 da Silva et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: We agree with the data availability policy of PLOS ONE and we have deposited data sets necessary to replicate the findings of our research in the repository Figshare, as suggested; DOI: 10.6084/m9.figshare.5212969; Link: https://figshare.com/s/ 624e1afb66a2a56515f9. Funding: MJS received a fellowship from Coordenac¸ão de Aperfeic¸oamento de Pessoal de Nı ´vel Superior (CAPES) and Conselho Nacional de Desenvolvimento Cientı ´fico e Tecnolo´gico (CNPq). VFS received a fellowship from Coordenac¸ão de