Carolina Genetic Corn: Seeds to Finished Product

by carolinastaff

Think about all the varieties of corn you’ve encountered—yellow corn, white corn, red corn, blue corn, and the thousands of products that contain corn. Have you thought about using corn to teach genetics? It’s the perfect, easy-to-use specimen. There’s no downtime waiting for plants to grow; offspring data are easy to obtain simply by counting kernels with specific traits; and the ears of corn are treated so they can be used many times.

Carolina has been producing genetic corn since 1967 and is the sole supplier of the product. What makes Carolina genetic corn special? Planting, harvesting, and preparing the corn is done by hand, ensuring every ear of corn yields Mendelian ratios so students can construct explanations for ratios and model genetic concepts. Here’s what we do to ensure you have the best possible product and your students have the best possible experience learning genetics concepts.

Our Corn Process

Corn is planted in plots that range in size from a few rows to 4 or 5 acres. The plots are at least 300 meters apart or separated by a natural barrier (wooded area) to prevent cross­ pollination between them (Fig. 1). Each year we plant between 20 and 30 of these plots. Corn in some plots is allowed to open-pollinate, while in other plots it is hand-pollinated.

1. Corn is planted in plots that range in size from a few rows to 4 or 5 acres.
FIGURE 1 The genetic com is planted in isolation plots, taking advantage of natural barriers as much as possible.

The life cycle of corn is simple and can be easily manipulated. Corn types are crossed by placing the pollen from one strain on the silks of another. While this procedure is simple, steps must be followed to insure that no foreign pollen lands on the the tops of immature ears, with silks that are just beginning to show or silks that would soon show are clipped (Fig. 2) to eliminate any unwanted early pollination. The clipped ear is immediately covered with a small bag called an ear bag. A mature tassel of the strain used as the pollinator is bagged with a tassel bag (Fig. 3).

Bags cover the clipped ears.
FIGURE 2 Silks are cut on immature ears.
FIGURE 3 The white bag covers a clipped ear, and the brown bag encloses the tassels.

The next day the tassel is shaken in the tassel bag and the pollen is transferred to the silks of the ear (Fig. 4). This is done by removing the ear bag and dusting the silks with the pollen from the tassel bag. The ear bag is replaced immediately after pollination.

FIGURE 4 Silks after pollination.

We give the corn constant attention as it grows, monitoring moisture needs and the presence of insects. Because mechanical harvesters can damage portions of the ears, all our genetic corn is harvested by hand (Fig. 5).

FIGURE 5 Carolina genetic corn is harvested by hand for top quality.
FIGURE 6 Carolina genetic corn is hand shucked.

The corn is harvested before it is completely dry, graded, and then dried in protective crates. After drying, the segregated ears are lacquer-treated to improve the appearance and to hold the seed firmly to the cob. The ears are individually wrapped in clear plastic and labeled.

The genetic corn is now ready for you and your students to begin a real-world application genetics study. Watch the videos below for additional information on the process. They’re a good introduction to agricultural science as well as genetics.

Genetic Corn Seeds

Genetic Corn Ears

176460 Corn Parent Ear, Yellow Sweet
176400 Corn Parent Ear, Purple Starchy
176450 Corn Parent Ear, Yellow Starchy
176540 Corn Segregating Ear, Su Endosperm Alleles 3:1
176500 Corn Segregating Ear, R Color Alleles 3:1
176600 Corn Segregating Ear, R and Su Alleles 9:3:3:1

Genetic Corn Kits

Mendelian Genetics of Corn Kit

This kit provides students the opportunity to examine Mendelian inheritance up close by scoring the inheritance patterns of traits on genetic corn ears and comparing results to those predicted by Punnett squares.

Monohybrid Genetics with Corn Kit

This is an introductory genetics activity for a beginning high school or middle school biology course. Students study the inheritance of grain color using ears of corn. Each grain is the F2 of a cross between a homozygous red corn and a homozygous white corn.

Carolina BioKits®: Corn Dihybrid Genetics

With this kit, students learn the basic principles of dihybrid inheritance and independent assortment using corn. Students first observe how traits of kernel color and nutrient composition pass from 1 generation to the next. Then they construct an hypothesis describing the mode of inheritance for each trait. This kit is designed for 30 students working cooperatively in pairs.

Genetic corn is used to teach quantitative analysis and statistics

Carolina Investigations® for AP® Biology: Quantitative Analysis and Statistics

Addresses AP® Biology Big Idea 3 and Essential Knowledge 3.A.3 and 3.C.1. This advanced kit reinforces data analysis, visualization, and statistical evaluation skills. An optional pre-lab inquiry illustrates the value of statistics when applied to hypothesis testing. Students then complete any or all 3 guided-inquiry activities to reinforce their understanding of Mendelian genetics, chi-square test for fit, and other concepts.

Genetic Corn Mounts

176900 Corn Mount, Dihybrid Cross
176810 Corn Mount, Monohybrid Cross

Genetic Corn Resources

Try one of our genetic corn activities:

Corn as an Introduction to Mendelian Genetics

Introduce your students to Mendelian genetics with this activity that uses parental stocks of yellow and purple corn.

Corny Genetics

Learn about how genetic corn offers a convenient and affordable way to effectively teach Mendelian genetics.

Carolina Quick Tips®: Next Top Model (Organism)

Students seem to consistently struggle to understand Punnett squares and grasp Mendel’s laws.

Genetic Corn Reviews

Corn Genetics is the perfect solution. Given the inevitable time crunch in the fall term, I have been frustrated with the time lost in raising fruit flies or growing plants. Corn genetics is the ideal way to teach Mendelian genetics efficiently and clearly. The subjects are easy to identify, easy to count, and easy to report on worksheets. This allows time to focus on the Chi Square test and to reflect on the many questions that always arise. Like, "Is each ear an offspring or each kernel?" and "Exactly how do these things reproduce?" and "If black is dominant, why is all the corn in the store yellow?" Another advantage is that it is real, as opposed to digital or virtual. And it can be reused as long as the kids are under control. It also allows the opportunity to spend a little time on writing and revising a more formal report. I can't imagine a better tool for genetics instruction.

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