Mapping quantitative trait loci for five forage quality traits in a sorghum-sudangrass hybrid

Abstract

ABSTRACT. The identification of quantitative trait loci (QTLs) affecting forage quality traits enables an understanding of the genetic mechanism of these loci. The aim of the present study was to detect QTLs for the wholeplant protein content (WP), whole-plant fat content (WF), neutral detergent fiber (NDF), acid detergent fiber (ADF), and whole-plant ash content (WA) using a population of 184 F 2 individuals from a cross between sorghum Tx623A and sudangrass Sa. Correlation analysis was performed between the five forage quality traits. WP was found to be positively correlated with WF, NDF, and ADF. Furthermore, NDF was positively correlated with ADF but negatively correlated with WA. A genetic map with 124 SSR markers was constructed for QTL mapping. A total of 12 QTLs associated with the five forage quality traits were detected. Of these QTLs, qNDF3, qNDF8, and qADF8 explained more than 10% of the phenotypic variation. Additionally, although all of the QTLs exhibited additive and dominant effects, they mainly exhibited dominant effects. Our results provide important information for marker-assisted selection breeding of sorghum-sudangrass hybrids.

Genome-Wide Association Studies for Five Forage Quality-Related Traits in Sorghum (Sorghum bicolor L.)

“…Of the 5 candidate loci for the CP content, 2 were already identified in the previous studies. The locus on chromosome 9 was mapped in the same region by Murray et al ( 2008 ) and Li et al ( 2015 ) in sorghum as well. Of the 3 candidate loci for the CL content, 2 were identified in the same region on chromosomes 2 and 8 by Murray et al ( 2008 ) and Shiringani and Friedt ( 2011 ).…”

“…The two types of fibers, NDF and ADF, are the two vital components of forage digestibility. Recently, the forage quality traits have been studied in sorghum and some related QTLs have been identified (Murray et al, 2008 ; Shiringani and Friedt, 2011 ; Li et al, 2015 ). However, these identified QTLs were observed to be less sensitive due to the limitation of linkage analysis based on bi-parental mapping populations.…”

Construction of ultra-high-density genetic linkage map of a sorghum-sudangrass hybrid using whole genome resequencing

“…ultra-high-genetic linkage map containing 5,656 SNP markers. Compared with previous maps, our maps are superior in terms of the mapping population size, high-throughput sequencing method, markers number, and sequencing data [20][21][22][23][24]29]. The genome coverage of our map was greatly improved, which may be attributed to several reasons: (1) The large genetic diversity between the two parents used in this study contributed to their significant difference in several important traits (Fig 1).…”

“…The difference types of molecular marker affect the accuracy of genetic linkage maps [17][18][19]. To date, more than 10 genetic maps of sorghum-sudangrass hybrid were mainly constructed by traditional first-and second-generation types of molecular markers such as amplified fragment length polymorphism (AFLP), restriction fragment length polymorphism (RFLP), simple sequence repeat (SSR), sequence associated amplified polymorphism (SRAP), and randomly amplified polymorphic DNA (RAPD) [20][21][22][23][24]. These maps contained 124-444 molecular markers, spanning 803.13-1468.12 cM, and the average distance between markers ranged from 2.98 cM to 8.84 cM.…”

Quantitative trait locus mapping for important yield traits of a sorghum-sudangrass hybrid using a high-density single nucleotide polymorphism map

“…Forage grass is a crucial material base of animal husbandry and the main source of livestock nutrition ( Li et al., 2015 ; Zhang et al., 2021 ). Plant height (PH), stem thickness (ST), tiller number (TN), leaf-related traits (leaf number (LN), leaf length (LL), and leaf width (LW), and fresh weight (FW) represent the most important yield traits.…”