Alexander Pavlista, UNL-PREC, 4502 Avenue I, 4502 Avenue I, Scottsbluff, NE 69361, United States of America, Carlos Urrea, Univ. of Nebraska - Research & Ext., 4502 Ave I, 4502 Ave I, Scottsbluff, NE 69361, United States of America, Gary Hergert, Panhandle R&E Center, 4502 Avenue I, 4502 Avenue I, Scottsbluff, NE 69361, United States of America, and James A. Schild, University of Nebraska, 4502 Avenue I, Scottsbluff, NE 69361.
To facilitate direct harvest of no-till dry bean, raising the lower pods is necessary. One way that
may accomplish this is to use the plant hormone gibberellic acid (GA3). Based on preliminary
greenhouse tests, the dry bean cultivars Matterhorn, a Great Northern class having a 2b growth
habit, and Poncho, a Pinto class having a 3b growth habit, were treated with GA3 in field trials
conducted at Scottsbluff in 2005. Seed of both cultivars was soaked for two minutes in water, or
GA3 at 125, 500 or 2000 ppm then dried before planting. Foliar treatments were applied at the
unifoliate stage. Foliar application rates of GA3 were 31.25, 125 and 500 ppm to Matterhorn, and
0.5, 2 and 8 ppm to Poncho. X77 was used as an additive and water with X77 was the control.
GA3 seed soak decreased Poncho's emergence but not Matterhorn's. The node of first trifoliate
leaves of Matterhorn was raised 2.5 cm (inch) with 500 ppm GA3 seed soak. Applied at the
unifoliate stage of both cultivars, the highest GA3 rates raised pods twice the distance of pods on
controls. Height to the second trifoliate node and to the lower pod beak was raised in both
cultivars. Cultivars differed in their sensitivity to GA3 rate regardless of application. Poncho was
much more sensitive than Matterhorn. Seed soaking was not predictable and was not as effective
as unifoliate application. Seed yield was not affected by GA3. Pod can be raised off the ground
by GA3 sufficiently to allow direct harvest and no-till production of dry beans is possible.
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