Stockbrokers often instruct investors to "spread their risk," or not put all their eggs in one basket.

Mid-South soybean farmers would be wise to follow the same advice agronomically by staggering the development of soybeans. This management practice enables the crop, or a large majority of it, to avoid problems caused by severe heat or drought conditions.

This can be accomplished through staggered planting dates, but may be more efficiently attained through planting soybeans of different maturity.

Mid-South soybean farmers are learning that Group IV varieties are effective ways to spread risk. Group IVs can be planted in mid-April to early May, and harvested by late August to early September. This allows the all-important seed fill prior to the often brutal temperatures in late July
and early August when the worst drought stress typically occurs.

An important aid to this early planting philosophy is the use of Roundup Ready® technology. While early soybeans can withstand spring's possible cool temperatures, their early growth might be slow which can give some weeds a headstart. In-plant protection plus a Roundup Ultra™ application as a burndown, followed by a second application within six weeks of planting offers cost-effective weed control.

Deltapine Seed in 1999 will introduce three new Group IV Roundup Ready varieties with agronomic qualities for early soybean production system. The bottom line is improved yield.

The new varieties, which will be on display at the Greenfield Seed Field Day in Harrisburg, Ark., next week include:

DP 4969 RR: a 4.9 maturity
DP 4750 RR: a 4.7 maturity
DP 4344 RR: a 4.3 maturity

Under the leadership of recognized soybean breeders Grover Shannon, Ph.D., and Chris Tinius, Ph.D., all Deltapine Roundup Ready varieties have been forward crossed, and are based upon the best genetics in the industry. Unlike some seed companies which developed their varieties in the North and Midwest and try to adapt them to Southern conditions, Deltapine Seed bred and tested all three varieties in research and test plots across the South. That is why Deltapine Seed is Your Southern Soybean Source™.

Varieties developed outside the Mid-South often are not resistant to stem canker and frogeye leaf spot. Stem canker can be a serious limiting factor of yields in southern soybeans.

Yields
Data from Research and Agronomic Services trials show Deltapine Seed's three new Group IV varieties produce better yields than other current varieties on the market (see chart).

Critical to achieving high yields is planting the variety that will respond best to the local environment and soil conditions. Deltapine Seed's development of these varieties over the past six years shows:

DP 4969 RR performs well in all soil types, but especially well in clay, heavy soils and poorly drained areas due to its tall plant type. This variety adapts to a wide geographic area, but a strength is its ability to move into Southern Mississippi and Louisiana. DP 4750 RR also performs well in all soils. Possesses a very strong early vigor and responds well to narrow row planting.
DP 4344 RR is proving the best choice for very early Group IVs, but growers need to be sure to manage this variety like an early Group IV. This is unlike the late IVs they are used to in
Mississippi, Louisiana and Arkansas. DP 4344 RR performs especially well in the mid-south areas of Tennessee, Missouri, Kentucky and even Illinois.


Increased Height Makes a Difference
An important characteristic of the Deltapine's new Group IVs is that they are bred for taller growth. Plant height is critical on Group IVs as they can 'shrink' in heavy clay or very early or very late plantings.

DP 4969 RR maintains height exceptionally well under tough ground or very early planting (late March) or as late as into June. DP 4730 RR grows to a medium height that holds up well.
DP 4344 RR is another tall variety for an early Group IV and maintains height exceptionally well under stress of early planting.

Bred for Stress Tolerance
Planting soybeans early is designed to help avoid stress, but that is not entirely possible. Knowing a variety's stress tolerance provides growers with greater peace of mind considering the unpredictable conditions encountered by Southern growers. DP 4969 RR yielded well in stressful
conditions in 1997 and this year shows up as the tallest and greenest variety in test plots in areas where heat stress has taken a heavy toll on others.

DP 4750 RR and DP 4344 RR in tests have proven to be "workhorses" that can handle a wide range of environmental conditions.

By Kelly Whiting, Ph.D.
Deltapine Seed
Soybean Product Service Manager

Roundup Ready® and Roundup Ultra™ are trademarks of Monsanto Company.
Your Southern Soybean Source™ is a trademark.

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