Evaluation of Sm1 Advanced Spring Wheat Lines for Resistance to the Wheat Midge

Objective:       

To evaluate spring wheat experimental lines for wheat midge resistance and agronomic performance in environments and cropping systems where the wheat midge is prevalent.

Results:

Four experimental spring wheat lines were evaluated for resistance to the wheat midge in comparison to the midge resistant and susceptible check varieties, Egan and Hank, respectively. This nursery was established at Kalispell and Conrad, MT. Midge populations were low to non-existent at both locations with the susceptible variety, Hank, having an average of only 0.7 and 4.6 larvae per spike at Conrad and Kalispell, respectively. As a result, it was not possible to assess the level of resistance expressed in the experimental lines.  However, the agronomic performance of the entries was determined.

At Kalispell, significant differences were observed for heading, height, stripe rust, yield, protein, test weight, and number of wheat midge per spike (Table 2). Heading averaged 178 days. Plant height averaged 33.1 inches and ranged from 30.2 inches for MT 1573 to 37.0 inches for Egan. Stripe rust was present in the nursery despite having been treated with a fungicide. Stripe rust infection averaged 13.4% and ranged from 4.3% for Egan to 35.0% for Hank. Tan spot also was present, and was significant at a probability level of 0.054 percent.  Tan spot infection averaged 13.8% and ranged from 0.0% for Egan, to 31.7% for MT1573. Yield averaged 91.1 bu/A, and ranged from 82.8 bu/A for Hank to 101.6 bu/A for Egan. Protein averaged 14.15%, and ranged from 13.47% for MT 1570 to 15.59% for Egan. Test weight averaged 59.9 lb/bu and ranged from 58.1 lb/bu for Hank to 61.3 lb/bu for MT 1570. The number of wheat midge per spike averaged 0.8. The susceptible variety Hank had 4.6 wm/spike while the resistant varieties afforded complete mortality.

At Conrad, no significant differences were observed for height, lodging, yield, test weight, protein or the number of larvae per spike (Table 3). Yields averaged 65.9 bu/A , but test weights were low, averaging 55.3 lb/bu. Proteins averaged 14.49 and all entries exceed 14% except for MT 1574.  Egan had the highest protein at 15.08 percent.

Summary:

The four experimental lines provided 100% midge control in Kalispell. However, in Conrad there was less than 1% infestation. Additionally, the experimental lines are significantly shorter than Egan in Kalispell but no differences were observed in Conrad. However, they produced lower yields than Egan.  Efforts should continue to identify short stature, high yielding, and midge resistant wheat lines.