Muir Woods National Monument. Long and big beautiful trees in a wood

Predicting phenotype from genotype is the fundamental challenge of genetics. In agriculture, understanding how genetics of plants determines — and doesn’t determine — how important crops respond to variations in soil, moisture, fertilizer, pests, and weather, so farmers can grow the food that sustains the world.

The importance of understanding the genetics of plants has been recognized throughout history. The first crops were domesticated about 12,000 years ago, and the twentieth century brought us statistical modeling of plant genetics and DNA-based selection of seed crops. But plant breeding is not solely the province of plant geneticists. Farmers, gardeners, landscapers, and your students can practice selective plant breeding.

How can you introduce the genetics of plants as a topic for student learning? You can begin with a discussion of malnutrition. Malnutrition describes the state of people who don’t get enough food. It also describes the state of people dealing with obesity.

You can provide context for your discussion of plant genetics by discussing how many people worldwide suffer from hunger and how many are obese. You can discuss the causes of hunger around the world. You can have your students apply their critical thinking skills to find out what is needed to address hunger in the world, the United States, their state, and their community. Be aware that this lesson may evoke some very personal stories of hunger.

Then, you can use the following six strategies for teaching the basic biology of plant genetics.

Genetics Of Plants – Start With The Basics

Even in the 2020s, students still need to know about Mendelian genetics. And even in the 2020s, most students still eat peas or refuse to eat peas but encounter them daily.

The peas you buy at the store will be uniformly green or uniformly yellow, the selection made by the food packer, but peas you grow in the garden will be green, yellow, or occasionally purple. If you have the space and your weather is warm enough, spend a few weeks growing your crop of Belinda, Century, Impala, Lenca, Miranda, Paloma, Renata, Tipu, or Victoria peas (available from online garden seed sellers).

Or show your class a video about Mendel and do a lesson on Mendelian genetics provided by a lesson source like Lesson Planet. Explain to your class that before 1970, this was as far as a high school biology lesson could go! Make sure your students have a firm grasp of the concept of dominant and recessive genes.

Illustrate How Every Individual Is A Mixed Bag Of Genes

Biology teachers all over the country teach about genetic drift with M&M candies. Every individual created by sexual reproduction receives half of its genes from its male parent and half from its female parent. So, have your students demonstrate how offspring can differ from their parents with a bag of M&M candies.

Start with a demonstration of the principles your students learned in their Mendelian genetics lesson. Ask them to demonstrate what happens when you cross a plant that yields green peas with a plant that yields yellow peas. Tell them that the plant yielding green peas is heterozygous, with one gene for green and one for yellow. Remind them that the yellow trait is recessive, so the plant yielding yellow peas will be a homozygote for this trait.

Have your students put ten green M&Ms and ten yellow M&Ms in a paper bag to represent the green-pea parent. Have them put 20 yellow M&Ms in a different bag to represent the yellow-pea parent.
Then have them take one M&M out of one bag and a second M&M out of the other. Ask them to describe the phenotype for which the pair of “peas” stands. Repeat this for all 20 pairings, and then ask your students what percentage of the pea pairings represent a plant with green peas and what percentage represents a plant that produces yellow peas.

Ask them how the outcome would be different if the green-pea parent had been homozygous for the green-color gene. Ask your students to repeat the game to determine the wrinkled or smooth phenotype distribution and purple versus white flowers.

Now, eat an M&M. Ask your students what happens when genes are deleted from the gene pool. Encourage your students to apply the same principle to other organisms, like people. For instance, ask your students how they could illustrate the genetics of the sickle cell trait in humans.

Move On To Four Advanced Topics

Candy has a way of keeping students engaged with a class, but only for a short time. Once you are sure everyone is on board with the basic concepts, give your students a hands-on demonstration of DNA. Reinforce the concept that genes are tangible.

Next, guide your students beyond the elementary level by leading them to think about how genes affect basic physiological processes in plants, like cellular respiration in seedlings. Find standard and fast-growing varieties of the same plant, and see if your students can measure differences in O2 consumption in a respiration chamber provided by Modern Biology. Have your students show you how plant pigments can be measured. Constantly have your students relate their observations to what they know about the plants they are using in their experiments.

Training young minds in the scientific method is made easier with Modern Biology. All our experiments let your students test a hypothesis. You will have a complete teacher’s guide with every experiment and receive all the safe, non-toxic reagents you need in every kit. Save yourself hours of ordering and inventory time, and never have to worry about running short of the materials you need for each lab.
Give your students an entirely new perspective on biology! Modern Biology has helped over 80,000 teachers keep over 500,000 students turned on to biology. Call us at (765) 446-4220 for more information today!