Biomedical Engineering Reference
In-Depth Information
detasseled prior to 5 % silk emergence, and less than 0.1 % of the pollen-parent
plant can be offtype at pollen release.
Sold seed must meet tag requirements stating that at least 98 % of the seed is the
hybrid listed. Purity determinations can be made using genetic markers or field
grow-outs of seed lots and graded samples. Waxy and amylose seed conform to
these requirements, but given the value-added nature of the grain, efforts are often
made to exceed 98 %.
Beginning with breeder seed, contamination evaluation must be as thorough and
as complete as is possible. Isolation distances far greater than 660 ft are commonly
used especially for the production of foundation seed, or if the pollen parent is not a
strong shedding inbred. Numerous field visits during the production are required to
monitor and execute rouging and removal of offtype materials.
Evaluation of ears prior to shelling provides a critical opportunity to use visual
phenotypic selection to remove any dent or obviously offtype ears. While ear
inspection is not feasible for large acreage productions, it can be a very important
step in breeder seed and small foundation increases. Pollen and seed parent syn-
chronicity is necessary to reduce blow-in contamination. Delayed pollen will result
in higher contamination at the base of the ear, whereas delayed silking can increase
contamination at the ear tip.
Kernels at the base of the ear tend to be larger rounds or flats and at the tip are
typically smaller rounds. A thorough evaluation of seed conditioning lots can
provide a very descriptive analysis of the production, and problematic seed lots
can be discarded. Because waxy and amylose seed productions are often smaller
than dent productions, attention must also be paid to postharvest contamination
sources. These include equipment cleanout and drier and bin-storage cleanouts to
reduce potential for contamination.
Market Challenges for Specialty Starch Maize
The major market challenge for the development of specialty starch hybrids is to
reduce production and grain premium costs. Premiums for waxy and amylose grain
are calculated based on formulations that take into account grain availability, local
costing basis, deliver costs, seed cost, increased cost for water, fungal or insecti-
cidal applications, specialty drying, costs of identity preservation, grain channeling,
and quality controls, but more than all of these things, the premium is paid based on
the yield of the specialty hybrid. All efforts have to be made to ensure the specialty
hybrid performance matches pace with yield advances in regular field corn.
Adaptation of the newest technologies provides new opportunities in breeding
for industrial maize starches, and those that are most profitable need to be captured
and capitalized. Importantly, markets need to be identified where industrial starches
are the go-to choice, either because of functionality, sustainability, or resource
availability. Specialty grain production is a growing market with many exciting
future possibilities.
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