Minnesota Crop News > 2001-2008 Archives
Maturities for Late-May Planted Corn
D. R. Hicks, Agronomy
and Plant Genetics
A major portion (76%) of the Minnesota corn
crop has been planted with the remainder delayed because of
wet soil conditions and growers may wonder about the maturities
of the hybrids they will be planting. Growers have made hybrid
choices based on maturities for their normal planting dates.
Growers should "stay the course" with their hybrid
choices if they can plant by or prior to May 25. If planting
does not occur by May 25, then consider maturities as given
in Table 1.
There are other reasons to "stay the course" with
the hybrids that growers have chosen. For the past several
years, growers in the southern 2/3 of the corn growing area
in Minnesota have chosen hybrids with maturities 5 to 10 less
than normally considered to be "full season". The
reasons for this have primarily been the excellent yields of
the earlier hybrids and the opportunity for an earlier harvest
period. So with the earlier hybrids, there is more calendar
time during planting that these hybrids will still be "maturity
adapted", i.e. they have a wider window for planting with
a high probability that the grain will reach full maturity
before the first killing frost.
Other reasons to "stay the course" are: Growers
have chosen their hybrids because of yield potential and experience
with some or all of their initial hybrids that they have chosen.
Changing to "earlier" hybrids may not result in the
best yielding hybrids in those maturities (assuming that growers
in more northern areas have already bought the best yielding
hybrids in those earlier maturities and there is little to
no seed left of these best yielding hybrids). And the physical
process of exchanging seed is logistically difficult to manage
for seed suppliers. Some growers may ask to exchange seed and
be successful, but exchanges would be difficult for all growers
Table 1. Recommended corn hybrid maturities or late planting.
||Relative Maturity Units
Earlier than Full Season1
|May 25 - May 31
||5 - 7 Relative Maturity
|Jun 1 - 10
||8 - 15 Relative Maturity
|Jun 11 - 15
||15 or more Relative Maturity
1For areas where 105 RM
hybrids are full-season, one should plant hybrids with maturity
ratings of 100 or less for grain production.