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Previous studies have identified wheat (Triticum aestivum L.) chromosome substitution lines between `Cheyenne' (CNN) and `Wichita' (WI) that contain quantitative trait loci (QTLs) affecting yield and yield components, anthesis date, plant height, and grain volume weight. However, chromosome substitution lines can only identify additive or epistatic gene action. In this study, hybrids between CNN and WI, and between chromosome substitution lines and their recurrent parents were evaluated in four field environments to determine if the QTLs exhibited additive and dominant gene action which could result in heterosis. As expected, the chromosome substitution lines were significantly different for grain yield from their recurrent parents, which indicated the chromosomes contained additive genes. Three of four chromosome substitution line hybrids were not different from the midparent value, which indicated predominantly additive gene action. However, the fourth substitution line hybrid significantly differed from the midparent value for grain yield, which indicated the chromosome contained genes that were heterotic and had dominant gene action. Some hybrids did not significantly differ from one parent, which further indicated the possibility of dominant gene action. Midparent heterosis also was identified in the cultivar hybrid for grain yield. High parent heterosis was not found for any of the measured traits. Hence, genes on these chromosomes exhibited predominantly additive gene action, but also exhibited dominant gene action which may explain some of the heterosis found in the cultivar hybrid., Previous research on reciprocal chromosome substitution lines between bread wheat cultivars `Wichita' (WI) and `Cheyenne' (CNN) determined that WI has major QTLs on chromosomes 3A and 6A that increased grain [...]

Chromosomal translocations between wheat (Triticum aestivum L.) and rye (Secale cereale L.) have been associated with an increase in grain yield and a decrease in end-use quality in hard red winter wheat. Although demonstrated with a 1BL.1RS translocation, less information is available regarding the effect of 1AL.1RS translocations. The objective of this study was to determine the effect of a 1AL.1RS translocation in hard red winter wheat on end-use quality traits and their stability across environments. From the heterogeneous 1AL.1RS wheat cultivar Nekota, 18 homogeneous 1A lines (non-1RS), 16 1AL.1RS lines, four composites (1A, 1AL.1RS, 1AL.1RS+ 1A, and Nekota), and six cultivars were tested in eight Nebraska environments. The 1AL.1RS translocation increased flour protein content (5.5 mg [g.sup.-1]), but decreased flour yield (14.2 g [kg.sup.-1]), Mixograph mixing time (from 2.9-2.7 min), and Mixograph mixing tolerance rating (from 3.5-3.1). Despite higher flour protein content in 1AL.1RS lines, the 1AL.1RS translocation did not enhance other end use quality traits. On the basis of linear regression, the 1A and 1AL.1RS lines had similar stability values for flour yield and flour protein content. The 1A lines showed higher flour yield in all environments, while the 1AL.1RS lines had higher flour protein content in all environments. For Mixograph mixing time and mixing tolerance, the 1A lines were more responsive to the environment, while the 1AL.1RS lines had exceptional stability over all environments. The end-use quality of Nekota can be explained by a mixture of 1A lines with acceptable to good quality and 1AL.1RS lines with poor to acceptable quality., The 1AL.1RS translocation originally found in `Amigo' has been widely used (Sebesta and Wood 1978; Sebesta et al., 1995; Friebe et al., 1996) and is in many wheat cultivars, such [...]

The presence of the short arm of rye (Secale cereale L.) chromosome one (1RS) has been associated with an increase in grain yield in hard red winter wheat (Triticum aestivum L.). This positive effect has been demonstrated when the 1RS arm is present in the 1BL.1RS translocation. However, little information is available regarding the 1AL.1RS transiocation. Our objective was to determine the effect of the 1AL.1RS translocation on yield and yield components and their stability across environments. Eighteen homogeneous 1A lines (non1RS) and 161AL.1RS lines were randomly derived from the heterogeneous cultivar Nekota. These 34 lines, four composites (IA, 1AL.1RS, 1AL.1RS + 1A, and Nekota), along with six check cultivars were grown in eight Nebraska environments. The 1AL.1RS transiocation in the Nekota background increased kernel weight (3.3%) and grain volume weight (0.4%); had no effect on grain yield, kernels per spike, and anthesis date; and decreased plant height (1.2%) and number of spikes per square meter (2.9%). The 1A lines and 1AL.1RS lines were equally stable for grain yield, kernels per spike, spikes per square meter, and plant height. For kernel weight, the 1A lines were more responsive and tended to have heavier kernels under favorable environments, while the 1AL.1RS lines had heavier kernels under lower yielding environments. For grain volume weight, the 1A lines were more responsive than the 1AL.1RS lines, which had heavier grain volume weight under lower yielding environments. Hence, the 1AL.1RS translocation in Nekota was not beneficial for either agronomic performance or stability., Translocations between wheat and rye have been successfully used to enhance genetic variability in wheat breeding programs. The translocation of the short arm of rye chromosome one (1RS) to the [...]