Genetic diversity and heterotic grouping of sorghum lines using SNP markers

Abstract

Sorghum breeding programs are based predominantly on developing homozygous lines to produce single cross hybrids, frequently with relatively narrow genetic bases. The adoption of complementary strategies, such as genetic diversity study, enables a broader vision of the genetic structure of the breeding germplasm. The purpose of this study was to evaluate the genetic diversity of sorghum breeding lines using structure analysis, principal components (PC) and clustering analyses. A total of 160 sorghum lines were genotyped with 29,649 SNP markers generated by genotyping-by-sequencing (GBS). The PC and clustering analyses consistently divided the R (restorer) and B (maintainer) lines based on their pedigree, generating four groups. Thirty-two B and 21 R lines were used to generate 121 single-cross hybrids, whose performances were compared based on the diversity clustering of each parental line. The genetic divergence of B and R lines indicated a potential for increasing heterotic response in the development of hybrids. The genetic distance was correlated to heterosis, allowing for the use of markers to create heterotic groups in sorghum.

Genetic Diversity and Population Structure of Sorghum [Sorghum Bicolor (L.) Moench] Accessions as Revealed by Single Nucleotide Polymorphism Markers

“…In the case of bi-allelic SNP markers, the maximum PIC value of 0.375 is attained when both alleles have a frequency of 0.5. In the present bi-allelic SNP-based study, the PIC values ranged from 0.09 to 0.375 with the overall average of 0.24, which is comparable with previous studies on sorghum using SNP markers ( Afolayan et al, 2019 ; Silva et al, 2021 ; Wondimu et al, 2021 ). Forty-seven percent of these SNP loci have a PIC value of greater than 0.25 and hence they are highly informative and could be used for various applications including population genetic studies of sorghum.…”

Heterosis and Inbreeding Depression in Grain Sorghum Hybrids

“…On the other hand, line A was closer, showing low variability, explained by the reduced number of existing male-sterility lines. These results corroborate those found by Jaikishan et al (2018), Silva et al (2021), andMenezes et al (2017). Silva et al (2021), studying the genetic distance between parental lines of Embrapa's grain sorghum hybrids, showed correlations between genetic distance and heterosis.…”

Unraveling the potential of phenomic selection within and among diverse breeding material of maize (Zea mays L.)

“…Likewise, broadening the genetic basis of a breeding program by introgression of less related material from different groups, as exemplified here with the landraces, will require testing this material but may also profit from the additional prediction of the expected performance. Furthermore, crops with yet undefined heterotic pools or the presence of subpopulations such as wheat ( Boeven et al 2016 ) or sorghum ( da Silva et al 2021 ) could benefit from the independence of the performance of phenomic prediction with regard to the training set composition and its possibly underlying population structure. In addition, breeding programs are driven by the different selection cycles, which by nature imply a decreasing relatedness of the individuals from one cycle to the next ( Schopp et al 2015 ; Auinger et al 2021 ).…”