|Gardner, C - PIONEER HI-BRED INTL|
|Henke, G - PIONEER HI-BRED INTL|
Submitted to: NCR-167 Corn Breeding Committee Meeting
Publication Type: Abstract Only
Publication Acceptance Date: February 16, 1998
Publication Date: N/A
Technical Abstract: Stalk brittle snapping refers to stalk snapping at a node from 30 to 60 cm above the ground when high winds occur. Brittle snapping usually happens when plants are turgid and during a window of susceptibility two to three weeks long, just before flowering. A device or procedure to measure brittle snapping is needed. The concept for the present device arose from a demonstration by Dr. C. A. C. Gardner, Pioneer Hi-Bred Intl., of manually causing brittle snapping. Kneeling/squatting down, she held the stalk with one hand ~12" above the ground and rapidly "struck" the stalk with her other hand held ~24" above the ground. The stalk either snapped, "squished" (broke, but did not snap), or did not snap. While this procedure worked, the physical cost was enormous and evaluation of large numbers of plots impossible. We constructed a tractor-mounted device with ATV wheels/tires placed horizontally to bend the stalk as it passed between the offset wheels. The top wheel was powered by a finely- regulated hydraulic motor so as to match ground speed and the bottom wheel was an idler. In operation, the idler wheel was kept against the row of stalks by using a guide bar mounted on the front of the tractor. Data observed were in agreement with Pioneer's brittle snapping ratings. A correlation of brittle snapping score (1=snaps, 9=does not snap) and brittle snapping percentage of r = -0.86* was obtained for combined data from three locations in 1997. Coefficients of variation of 22-26% were found across the three locations. With a high-boy carrier, the device can be effectively used for selection as well as hybrid characterization.