Identification of phenotypic differences associated with wheat stem sawfly (Cephus cinctus) resistance in near isogenic lines of spring wheat

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Presenting Author(s)

Megan Hager

Montana State University
Bozeman, Montana

Co-Author(s)

Jose Ricardo Lima Pinto

São Paulo State University (UNESP)
jaboticabal, Brazil
Buddhi Bahadur Achhami

Montana State University
Laissa Cavallini

Bozeman, MT
MH

Megan Hofland

Montana State University
Bozeman, Montana
LH

Lila Hamburg

Montana State University
Bozeman, Montana
Lochlin Scott Ermatinger

Bozeman, MT
SP

Scott Powell

Montana State University
Bozeman, Montana
Robert K.D Peterson

Montana State University
Bozeman, Montana
DW

David Weaver

Montana State University
Bozeman, Montana

Wheat stem sawfly (WSS), Hymenoptera Cephus cinctus Norton, is a major pest of spring wheat, Triticum aestivum L., in North America. Adult WSS oviposit in the stem, and the stem boring of the larvae negatively impacts photosynthesis, causing yield loss. The larvae travel to the base of the plant and cut a ring around the inside of the stem which causes lodging and makes harvesting heads difficult. The stem solidness trait provides WSS tolerance and is associated with the QTL Qss.msub-3BL. In near isogenic lines (NILs), the 3BLc allele is responsible for early stem solidness that offers the plant some resistance to infestation. When compared with the 3BLb allele, 3BLc is also associated with a decreased number of ovipositor insertions and number of eggs laid. This study uses hyperspectral imaging and photosynthetic measurements to identify visual and chemical differences between NILs containing the 3BLb and 3BLc alleles. A greenhouse study was conducted using six plants from each line at Zadok’s stage 32 and Zadok’s stage 49. A significantly higher photosynthetic rate was observed in 3BLc lines, however hyperspectral images showed no difference in the spectral signatures of these 3BLb and 3BLc lines. At Zadok’s stage 32 there was significantly higher intercellular carbon concentration and rate of transpiration. These differences may help determine host plant attractiveness by influencing the behavior of female sawflies.