Agronomic and quality impact of a shortened translocation for wheat streak mosaic virus resistance

Wheat streak mosaic virus (WSMV) is a mite-vectored virus with substantial
economic impact on wheat production. One of the effective sources of
resistance to WSMV, Wsm1, is carried on a translocation from Thinopyrum
intermedium. The original whole arm form of this translocation (T4DL·4JsS)
was highly effective against WSMV but carried a substantial yield penalty
in the absence of the virus. Shorter recombinants of the Th. intermedium
translocation are now available. This study characterized the agronomic
performance of near-isogenic sib-pair families in ten yield trials using
one of these shortened T4DL·4DS-4JsS translocations, named ‘rec213’, in
the absence of visible disease. This translocation had no effect on
heading date, was associated with a modest reduction (≤ 4.8 cm) in plant
height, and the translocation had a favorable effect (≤ 12.6%) on grain
yield in those environments where highly significant genotype effects were
detected. The translocation did not affect protein concentration or lactic
acid-sodium dodecyl sulfate solvent retention capacity, a measure of
gluten quality. However, families with the translocation had slightly (≤
5%) lower protein quality scores than paired families without the
translocation. We do not expect this modest difference in quality to be a
barrier to utilization of the rec213 translocation for Wsm1, but we
encourage breeders to work within high quality genetic backgrounds in when
using the rec213 translocation, and to monitor the quality of breeding
selections. Improved codominant PCR-based marker assays were developed to
facilitate the use of the rec213 Wsm1 trait in breeding programs.