The 1BL/1RS Translocation: Agronomic Performance of F3‐Derived Lines from a Winter Wheat Cross

Cultivar comparisons have suggested that the 1BL/1RS wheat ( Triticum aestivum L.)‐rye ( Secale cereale L.) chromosomal translocation enhances agronomic performance and environmental stability of wheat. This advantage has been attributed either to disease resistance genes or to unproved adaptation genes on the 1RS segment. The objective of this study was to determine the effect of 1BL/1RS without the confounding effect of cult!var background by evaluating 17 homogeneous 1B, 20 heterogeneous 1B:1BL/1RS, and 22 homogeneous 1BL/ 1RS lines. The lines were randomly selected from the cross ‘Siouxland’/ ‘Ram’. The 59 progeny lines and the two parents were tested in seven Nebraska field environments with a randomized complete‐block design. Data were obtained for grain yield, components of yield, grain volume weight, anthesis date, plant height, and leaf rust infection. The 1BL/ 1RS class was 9% higher yielding than 1B and heterogeneous classes. This yield advantage was attributed to increased kernel weight, which was generally expressed in lower yielding environments. Differential response to disease pressure did not explain yield differences. Within chromosome classes, differences in grain yield were attributed more to variation in number of spikes per square meter not kernel weight. The grain yield advantage of the 1BL/1RS appeared to be associated with a postanthesis stress tolerance, which resulted in increased kernel weight of the 1BL/1RS genotypes.