Skip to main content
ARS Home » Midwest Area » Columbia, Missouri » Plant Genetics Research » Research » Publications at this Location » Publication #78776
Title: USE OF THE RADIOISOTOPE AMERICIUM 241 TO MEASURE CORN STALK NODE DENSITY AND IT'S ASSOCIATION WITH BRITTLE SNAPPING

Author
item Darrah, Larry
item MILLER, W - UNIV OF MISSOURI
item YIN, X - UNIV OF MISSOURI
item GARDNER, C - PIONEER HI-BRED INTL

Submitted to: NCR-167 Corn Breeding Committee Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 2/24/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Stalk brittle snapping refers to 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. Area of particular vulnerability are Nebraska, eastern Kansas, and western Missouri, but it can occur anywhere with very strong winds. Working from a suggestion that density in the nodal plate area might be associated with brittle snapping, we evaluated a non-destructive method of measuring density by using gamma-ray attenuation with an Americium 241 sealed gamma-ray source (12 mCi, 60 keV energy, 432 year half-life) mounted to a caliper that measured stalk diameter. A detector (CdTe) was also mounted on the caliper and connected to a portable counter (Ludlum model 2200) for measuring transmitted cpm (counts per minute). Using stalk diameter and cpm data, a density calculation was made. Of six points measured on the stalk, only the measurement at 3rd node ( " above the nodal plate line) above the 2nd elongated internode above ground level was consistent with test hybrid rankings for brittle snapping score. In this instance, lower density was associated with less brittle snapping. Critical issues include measuring in the appropriate time window and at the best node. With the source used, special training was needed for transportation and usage. Measurements take 10-15 sec/plant and individual plant measurements were variable; plot means are probably necessary. Characterization of hybrids is possible, but there may be better ways of measuring brittle snapping that would allow nursery application.