Characterization of the determinants of economically important phenotypes
showing complex inheritance should lead to more effective use of genetic
resources. This study was conducted to determine the number, genome location and
effects of QTLs determining malting quality and agronomic traits in the two North
American barley quality standards. Using a doubled haploid population of 140 lines
from the cross of Harrington x Morex, agronomic phenotype and malting quality
data sets from nine and eight environments, respectively, and a 107-marker linkage
map, QTL analyses were performed using simple interval mapping and simplified
composite interval mapping procedures. Thirty five 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).
Thirteen QTLs were associated with five malting quality traits (grain protein
percentage, soluble/total protein ratio, ��-amylase activity, diastatic power and malt
extract percentage). QTLs for multiple traits were coincident. The loci controlling
inflorescence type [vrsl on chromosome 2 (2H) and int-c on chromosome 4 (4H)]
were coincident with QTLs affecting all traits except heading date and malt extract
percentage. The largest effect QTLs -for yield, kernel plumpness test weight, plant
height grain protein percentage, S/T ratio, and diastatic power- were coincident
with the vrsl locus. QTL analyses were conducted separately for each sub-population
(six-rowed and two-rowed). Ten new QTLs were detected in the sub-populations.
There were significant interactions between the vrsl and int-c loci for
plant height, grain protein percentage, and SIT protein ratio. Positive transgressive
segregants were found for all agronomic traits. They were more prevalent in the
six-rowed sub-population, indicating that more favorable alleles were fixed in the
two-rowed parent. Results suggest that this mating of two parents representing
different germplasm groups caused a disruption in the balance of traits involved in
malting quality, which resulted in no progeny carrying all favorable alleles and
therefore surpassing the quality of either parent. This study describes some of the
genetic determinants of agronomic and malting quality traits in a two-rowed x six-rowed
cross and it is a first step toward the further characterization and
manipulation of these determinants. / Graduation date: 2001
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/32603 |
| Date | 04 August 2000 |
| Creators | Marquez-Cedillo, Luis A. |
| Contributors | Hayes, Patrick M. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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