QTL analysis of agronomic traits in barley based on the doubled haploid progeny of two elite North American varieties representing different germplasm groups

Abstract

A better understanding of the genetics of complex traits, such as yield, may be achieved by using molecular tools. This study was conducted to estimate the number, genome location, effect and allele phase of QTLs determining agronomic traits in the two North American malting barley (Hordeum vulgare L.) quality variety standards. Using a doubled haploid population of 140 lines from the cross of two-rowed Harrington×six-rowed Morex, agronomic phenotypic data sets from nine environments, and a 107-marker linkage map, we performed QTL analyses using simple interval mapping and simplified composite interval mapping procedures. Thirtyfive QTLs were associated, either across environments or in individual environments, with five grain and agronomic traits (yield, kernel plumpness, test weight, heading date, and plant height). Significant QTL×environ-ment interaction was detected for all traits. These interactions resulted from both changes in the magnitude of response and changes in the sign of the allelic effect. QTLs for multiple traits were coincident. The vrs1 locus on chromosome 2 (2H), which determines inflorescence row type, was coincident with the largest-effect QTL determining four traits (yield, kernel plumpness, test weight, and plant height). QTL analyses were also conducted separately for each sub-population (six-rowed and two-rowed). Seven new QTLs were detected in the sub-populations. Positive transgressive segregants were found for all traits, but they were more prevalent in the six-rowed sub-population. QTL analysis should be useful for identifying candidate genes and introgressing favorable alleles between germplasm groups.

Localization of Quantitative Trait Loci for Yield Components in a Cross Oriental ^|^times; Occidental Barley Cultivar (Hordeum vulgare L.)

“…GWT was controlled predominantly by vrs1 and uzu as detected previously 3,5,15,23 . The allele of Azumamugi at the vrs1 locus increased GWT by 9.15-11.75 g ( Table 4).…”

“…A LOD score threshold of 3.0 was used to identify QTLs. The position of detected QTLs were compared with the ones of former QTL studies 1,3,10,15 consulting integrated maps 6,16 .…”

A new genetic linkage map of barley (Hordeum vulgare L.) facilitates genetic dissection of height and spike length and angle

“…Furthermore, their plant height QTL is bordered by alm locus, which is placed in 3H-Bin 3 (next to btr1 locus) http://wheat.pw.usda.gov/ cgi-bin/graingenes/report.cgi?class=marker&name=alm and by the marker FGX OWB00380, which corresponds to marker 12 31017 located at 56.40 cM on 3H . Another study on barley plant height identified QTL on chromosome 3H at 67-78 cM (Marquez-Cedillo et al, 2001). Comparison of QTL flanking markers, from Marquez-Cedillo et al study and our study, in barley integrated genetic maps at the GrainGenes website (http://wheat.pw.usda.gov) suggested that our QTL was in a different genetic location than the QTL from Marquez-Cedillo et al study.…”

QTL analysis of flag leaf in barley (Hordeum vulgare L.) for morphological traits and chlorophyll content

“…It was found that some flag leaf traits, such as length, width and angle, were inherited quantitatively (Yang and Lu, 1991 Meanwhile, quantitative trait loci (QTL) mapping provides a powerful tool to study complex traits at the molecular level, and considerable progress has been made in the genetic research on yield, yield components, and malting quality traits in barley (Backes et al, 1995;Baum et al, 2003;Bezant et al, 1997;Kjaer and Jensen, 1996;Li J.Z. et al, 2005;Marquez-Cedillo et al, 2001;Mather et al, 1997;Sameri et al, 2006;Thomas et al, 1995;Yin et al, 1999). However, little research has been done in understanding of genetic mechanisms for flag leaf traits in barley.…”