Agronomic Impact of a Stem Solidness Gene in Near‐Isogenic Lines of Wheat

Abstract

ABSTRACTThe primary trait in wheat (Triticum aestivum L.) to prevent damage caused by the wheat stem sawfly (WSS) (Cephus cinctus) is antibiosis facilitated by solid stems. The pith of solid stems impedes development of larvae, often resulting in their death inside the stem. A key question regarding solid stems is the possible impact on grain yield potential due to photosynthate partitioning to stem pith instead of to grain. Molecular markers for the major gene controlling stem solidness, Qss.msub‐3BL, were used to develop near‐isogenic lines (NIL) for alleles at Qss.msub‐3BL in six genetic backgrounds. The NIL were grown in replicated trials in 12 locations that varied for yield potential in Montana, Washington, and Idaho. There was no significant impact of the solid stem allele on grain yield based on mean performance over recurrent parents and locations. Individually, solid‐stemmed NIL were significantly lower yielding in one of six genetic backgrounds. Based on means over all crosses, the solid‐stemmed NIL had lower yield in only one high‐yielding environment. These results suggest that in general the allele for solid stems at Qss.msub‐3BL does not result in yield reduction. Development of solid‐stemmed cultivars with yield potential similar to the best hollow‐stemmed cultivars is a reasonable goal for wheat breeding programs in areas impacted by the WSS.