Natural variation and genetic loci underlying resistance to grain shattering in standing crop of modern wheat.

Modern wheat (Triticum aestivum L.) cultivars have a free-threshing habit, which allows for easy manual or mechanical threshing. However, when harvesting is delayed or extreme weather events occur at harvest time, grain shattering can cause severe loss of harvestable yield.

The Locus on Wheat Chromosome 2B Controls Major Natural Variation for Floret Sterility Responses to Heat Stress at Booting Stage.

Heat stress at booting stage causes significant losses to floret fertility (grain set) and hence yield in wheat ( L.); however, there is a lack of well-characterized sources of tolerance to this type of stress. Here, we describe the genetic analysis of booting stage heat tolerance in a cross between the Australian cultivars Drysdale (intolerant) and Waagan (tolerant), leading to the definition of a major-effect tolerance locus on the short arm of chromosome 2B, ().

Unravelling the Complex Genetics of Karnal Bunt () Resistance in Common Wheat () by Genetic Linkage and Genome-Wide Association Analyses.

Karnal bunt caused by Mitra [syn. (Mitra) Mundkur] is a significant biosecurity concern for wheat-exporting countries that are free of the disease. It is a seed-, soil-and air-borne disease with no effective chemical control measures.

Development of SNP assays for hessian fly response genes, Hfr-1 and Hfr-2, for marker-assisted selection in wheat breeding.

Background: The Hessian fly response genes, Hfr-1 and Hfr-2, have been reported to be significantly induced in a Hessian fly attack. Nothing is known about the allelic variants of these two genes in susceptible (S) and resistant (R) wheat cultivars.

Results: Basic local alignment search tool (BLAST) analysis of Hessian fly response genes have identified three alleles of Hessian fly response gene 1 (Hfr-1) on chromosome 4AL and 7DS, and 10 alleles of Hessian fly response gene 2 (Hfr-2) on chromosome 2BS, 2DL, 4BS, 4BL, 5AL and 5BL.

A QTL on the short arm of wheat (Triticum aestivum L.) chromosome 3B affects the stability of grain weight in plants exposed to a brief heat shock early in grain filling.

Background: Molecular markers and knowledge of traits associated with heat tolerance are likely to provide breeders with a more efficient means of selecting wheat varieties able to maintain grain size after heat waves during early grain filling.

Results: A population of 144 doubled haploids derived from a cross between the Australian wheat varieties Drysdale and Waagan was mapped using the wheat Illumina iSelect 9,000 feature single nucleotide polymorphism marker array and used to detect quantitative trait loci for heat tolerance of final single grain weight and related traits. Plants were subjected to a 3 d heat treatment (37 °C/27 °C day/night) in a growth chamber at 10 d after anthesis and trait responses calculated by comparison to untreated control plants.

Genetic control of grain yield and grain physical characteristics in a bread wheat population grown under a range of environmental conditions.

Genetic analysis of the yield and physical quality of wheat revealed complex genetic control, including strong effects of photoperiod-sensitivity loci. Environmental conditions such as moisture deficit and high temperatures during the growing period affect the grain yield and grain characteristics of bread wheat (Triticum aestivum L.).

Genetic variation and possible SNP markers for breeding wheat with low-grain asparagine, the major precursor for acrylamide formation in heat-processed products.

Background: In products made from wheat (Triticum aestivum) flour, acrylamide formation is almost exclusively determined by the level of free asparagine in the grain. Genetic variability for grain asparagine content was evaluated in order to assess the potential for acrylamide mitigation by breeding.

Results: Free asparagine levels in the grains of 92 varieties varied from 137 to 471 mg kg⁻¹, representing an approximate threefold difference between the low- and high-asparagine genotypes.

QTL dissection of the loss of green colour during post-anthesis grain maturation in two-rowed barley.

Ability to genetically manipulate the loss of green colour during grain maturation has potentials for increasing productivity, disease resistance, and drought and heat tolerance in crop plants. Two doubled haploid, two-rowed barley populations (Vlamingh × Buloke and VB9524 × ND11231*12) were monitored over 2 years for loss of green colour during grain filling using a portable active sensor. The aims were to determine the genomic regions that control trait heritability by quantitative trait locus (QTL) analysis, and to examine patterns of QTL-environment interactions under different conditions of water stress.

Genome-wide association analyses of common wheat (Triticum aestivum L.) germplasm identifies multiple loci for aluminium resistance.

Aluminium (Al3+) toxicity restricts productivity and profitability of wheat (Triticum aestivum L.) crops grown on acid soils worldwide. Continued gains will be obtained by identifying superior alleles and novel Al3+ resistance loci that can be incorporated into breeding programs.

An EST-SSR marker tightly linked to the barley male sterility gene (msg6) located on chromosome 6H.

The barley male sterility gene (msg6) located on chromosome 6H has been used in breeding and research since its discovery 7 decades ago, but to date, no research has been reported that linked the gene with molecular markers. The main objective of this study was to identify expressed sequence tag-simple sequence repeat (EST-SSR) markers linked to msg6 as this could provide opportunities for gene discovery. In a cross of a male sterile line (04-042B) with a fully fertile line (VB0330; VB9524/Mundah), male sterility segregated in a 3:1 ratio of fertile to completely sterile plants (χ(2) = 0.

EST-SSR markers derived from an elite barley cultivar (Hordeum vulgare L. 'Morex'): polymorphism and genetic marker potential.

Microsatellites or simple sequence repeats have become the markers of choice for marker-assisted selection because of their low template DNA requirement, high reproducibility, and high level of polymorphism. This study investigated a new set of barley (Hordeum vulgare L.) EST-derived SSR markers designed to target gene sequences expressed during grain development, as they are more likely to be important in determining grain quality.