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

Abstract

The 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.

Evaluation of a QTL Mapping Population Composed of Hard Red Spring and Winter Wheat Alleles Using Various Marker Platforms

“…Sequence information for the sequence‐based SNPs that were found to be associated with solid stems in this study can be found in Supplemental Table S1. Lastly, previous studies found no significant correlation between yield and the solid‐stem trait (Cook et al, 2004; Sherman et al, 2015), but in this study, a significant negative correlation of −0.25 ( P < 0.05) was identified between the solid‐stem trait and yield in rainfed environments (Table 2). The significant negative correlation found in this study between the solid‐stem trait and yield demonstrates that solid‐stem varieties may suffer a yield penalty in some genetic backgrounds and environments.…”

Association Analysis of Stem Solidness and Wheat Stem Sawfly Resistance in a Panel of North American Spring Wheat Germplasm

“…A recent genetic study using near-isogenic lines for the Qss.msub-3BL showed that the allele for solid stems did not have a negative effect on grain yield (Sherman et al, 2015) based on yield trials conducted over nine environments. Limitations constraining other potential control measures have driven pest management efforts toward resistance breeding.…”

“…This is likely due to the introduction of stem solidness into germplasm of the Northern Great Plains in the middle of the 20th century and subsequent introgression of the genes for stem solidness into lines targeted specifically for WSS-impacted areas. A recent genetic study using near-isogenic lines for the Qss.msub-3BL showed that the allele for solid stems did not have a negative effect on grain yield (Sherman et al, 2015) based on yield trials conducted over nine environments. However, there was also no advantage to the allele for solid stems in the absence of WSS, thus, the solid stem allele is absent or present at low frequencies in most germplasm.…”

Farming system and wheat cultivar affect infestation of, and parasitism on, Cephus cinctus in the Northern Great Plains

“…28 Increased resistance of wheat to C. cinctus has been accomplished by developing solid-stemmed cultivars that reduce egg deposition and decrease survival of eggs and larvae. 5,[29][30][31] However, solid-stem wheat cultivars often yield less than the traditional hollow-stemmed cultivars 5,32,33 (but see Sherman et al 34 ) and limit parasitism of C. cinctus 35 (but see Weaver et al 18 and Wu et al 36 ). Because penetration of the stem and host location are more difficult for parasitoids; 37 the efficacy of hollow-stemmed wheat is also dependent on the availability of preferred alternative hosts.…”