|Des Moines, Iowa
Most producers across the Corn
Belt are busy planting their 1999 corn crop. In some cases, cool, wet weather could hamper
and delay planting, limiting the number of growing days until harvest and causing some
growers to consider earlier maturing hybrids.
But long-term research from Pioneer Hi-Bred
International, Inc., as well as studies from several universities, shows that adapted,
full-season corn hybrids often offer the best yield and profit advantage in these
"Full-season hybrids typically make full use of a growing season," says Raj
Iragavarapu, agronomy research information specialist with Pioneer. "However, even
when planted late, these hybrids often outperform early maturing hybrids, adjusting their
growth and development to reach maturity in a shortened growing season."
According to Iragavarapu, early hybrids should be used under certain late-plant or replant
situations. But it may be best to wait a little longer before switching to these earlier
"If growers have questions about switching, including replacement hybrid
availability, they should consult their Pioneer sales professional," says
University research shows that full-season hybrids adjust to late planting with a
reduction in growing degree units (GDUs) of up to six units per day of planting delay.
Averaged over all hybrids, locations and years, 240 fewer heat units were required when
planting was delayed 40 days from the optimum planting date.
Twelve years of Pioneer studies reinforce the university findings. Pioneer focused on
hybrids planted across the central, north central and far north regions of the Corn Belt
from 1987 to 1998. Hybrids were planted from early April to mid-June and grouped into
full, medium and early maturities at each location. The studies looked at differences in
corn grain yield response to
planting date, as well as moisture, test weight and gross income response. The data gives
growers more relevant planting information for the different regions in which they farm.
For example, in the central Corn Belt, results indicate that late-April planting is best
for optimum corn yield potential. Full-season hybrids hybrids with a comparative
relative maturity (CRM) of 110 or later yield better and produce better grain at
harvest than early maturity hybrids. Growers should not consider switching to earlier CRM
hybrids until the first week of June.
Soil conditions permitting, April planting also is recommended in the north Central Corn
Belt. Growers are encouraged to plant full-season hybrids (103 CRM or later) until the
last week of May in this region.
Maturity planning is most critical in northern-most states because of the risk of cool
weather or early frost. Pioneer recommends producers in these regions stick with
full-season hybrids (100+ CRM) until the 25th of May. Growers with questions about
specific hybrid characteristics and
environmental effects should talk to their seed sales professionals.
Pioneer Hi-Bred International, Inc., (NYSE-PHB) is the
world's leading supplier of agricultural genetics and is the leading developer and
integrator of agricultural technology. Headquartered in Des Moines, Iowa, Pioneer
develops, produces and markets a full line of seeds, forage and grain
additives and services to grain and livestock producers, grain processors and other
Company news release