Phenotypic and molecular characterization of sweet sorghum accessions for bioenergy production

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 program; to examine the relationship between the phenotypic and the molecular diversity matrices; and to infer about the population structure in the sweet sorghum accessions. Morphological 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 background 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.

Characterization and performance of castor bean lineages and parents at the UFRB germplasm bank

“…It is important to characterize the germplasm in field conditions to verify its performance in normal conditions, [18] evaluating 100 accessions of sorghum sorghum verified a significant contribution of morphological and agroindustrial characteristics related to the production of sugar and biomass, being 53.1% for the analysis of phenotypic diversity.…”

Comparative assessment of genetic diversity matrices and clustering methods in white Guinea yam (Dioscorea rotundata) based on morphological and molecular markers

“…The inconsistency between the clusters identified by the genotypic and phenotypic information could also be attributed to the enormous genotype-by-environment interaction effects generally observed for quantitatively inherited morphological and agronomic traits. The lack of correlation between the molecular and the morphological diversity matrices further emphasizes the non-overlapping and complementarity between the genotypic and the phenotypic information to dissect the nature and extent of genetic diversity in crops 39 , 40 . Several studies have also reported inconsistencies between phenotypic and genotypic distances in different crops 41 – 43 .…”

“…An approach that combines the phenotypic and genotypic dissimilarity matrices into a single matrix for genetic diversity assessment was suggested to capture the entire genetic variability in plant populations 40 , 44 . The application of joint analysis for phenotypic and molecular information identified three genetic groups in the current set of materials highly valuable for genetic improvement in white Guinea yam.…”

General and specific combining ability in sweet sorghum

“…R-lines were developed from breeding populations obtained from crosses involving traditional varieties, such as Wray, Brandes, and Theis (Silva et al 2017). A-lines were obtained from breeding populations of crosses between elite R-lines with high sugar content and B-maintainer lines rich in juice with low sugar content.…”