Response of Corn to Low‐Rate Foliar Sprays of Dinoseb¹

Abstract

Corn (Zea mays L.) producers have expressed widespread interest in using low rate foliar sprays of 2‐sec‐butyl‐4,6‐dinitrophenol (dinoseb) as a growth regulator to enhance grain yield. In four experiments conducted at two locations during a 2‐year period, dinoseb was applied as nearly as possible to 3 weeks before tassel emergence to evaluate its effect on yield. Rates of 0, 7.4, 12.4, and 24.7 g dinoseb/ha were used in all experiments, and five adapted commercial hybrids and one two‐ear synthetic were used in the different experiments. Dinoseb applied to four hybrids at one location in 1975 caused a 6 to 8% yield decrease and a 1 to 2% increase in barrenness. An increase in nubbin ears (less than 40 kernels per ear) was also associated with the yield loss. During 1976, yield of the synthetic increased 4% at the 12.4 and 24.7 g/ha dinoseb rates, but a commercial hybrid in the same trials was not affected by treatment. Dinoseb affected the formation of second ears with both increases and decreases in this trait being observed at similar chemical rates. It is concluded that in these experiments corn responded in an unpredictable manner with dinoseb applications to different genotypes in different environments.

Dinoseb and Triacontanol as Growth Regulators in Irrigated and Nonirrigated Field Corn1

“…There were no significant yield decreases due to dinoseb in the 48 comparisons, and the overall mean response was a 3.8 kg/ha yield decrease. Johnson et al (7) reported inconsistent response to dinoseb, including highly significant grain yield decreases in some corn cultivars. Yield decrease was attributed to increased ear barrenness and nubbin ears.…”

“…Ries et al (13) subsequently observed an increase in shoot dry weight of field corn ('Michigan 396') and six other field and greenhouse crops following foliar applications of triacontanol. Sagaral et al 7 reported increased shoot and pod weight in bean (Phaseolus vulgaris L. 'Black Valentine'), whereas in corn ('Funks G4646') there was an increase in height but not in shoot dry matter. In field-grown sweet potato [Ipomoea batatus (L.) Lam], triacontanol increased percent dry matter immediately after application, and increased percent leaf N, but had no effect on roots or yield (1).…”

“…While certain crops under certain conditions have shown increased growth and economic yield in response to dinoseb and triacontanol, few consistent patterns have emerged as to the circumstances favoring yield increases. With dinoseb, for example, precise timing (6, Oplinger) and rate (7,9) of application have not been prerequisite for a yield response. Similarly, a wide range of rates and application procedures stimulated yield response to triacontanol (13,14).…”