Introduction to Wisconsin Fast Plants® Phenotypes

A Carolina Essentials™ Investigation

Total Time: 30 mins

Prep: 30 mins | Activity: 30 mins

Life Science


High School


In this scientific inquiry activity, students investigate phenotypes using Wisconsin Fast Plants® seeds. After the seeds germinate, students identify the phenotypes and the possible associated genotype. Students can investigate possible Mendelian crosses by completing Punnett squares using the phenotypes they identified. If time permits, students can perform plant crosses of different phenotypes and determine if the predicted phenotypes from the Punnett squares appear in the F1 generations.

Essential Question

What are the typical variations in traits, or phenotypes, found in Wisconsin Fast Plants®?

Investigation Objectives

  1.  Observe differences in phenotypes in Wisconsin Fast Plants®
  2.  Predict the possible phenotypes resulting from various parent crosses.

Next Generation Science Standards* (NGSS)

Science & Engineering Practices

Developing and Using Models

Disciplinary Core Ideas

LS3: Heredity: Inheritance and Variation of Traits

Crosscutting Concepts



Safety and Disposal

Ensure that students understand and adhere to safe laboratory practices when performing any activity in the classroom or lab. Use personal protective equipment such as safety glasses or goggles, gloves, and aprons when appropriate. Require students to adhere to all laboratory safety rules.


Dry plants out completely, place them in a resealable bag, and dispose of them in the trash. Plants may be allowed to continue to grow for additional investigations.

Student Procedures

  1. Place a filter paper or paper towel disk in the bottom of a petri dish. The paper should cover the bottom.
  2. Space the 10 seeds out evenly on the filter paper.
  3. Use the spray bottle to moisten the seeds and paper. The paper should be damp, but not sitting in a puddle.
  4. Cover the petri dish and place it under a flexible lamp or plant light bank.
  5. Observe the seeds daily for 4 or 5 days, or as directed by your teacher. Record your observations on the data sheet.
  6. Use the spray bottle to mist the seeds as needed. They should be kept moist, but not wet.

Teacher Preparation and Tips

  1. If you are using paper towels, cut them into disks to fit the bottom of the petri dishes prior to the activity. If the paper towels are thin, 2 layers may be necessary to keep the seeds moist.
  2. To save time, count out 10 seeds for each student or group before the activity.
  3. Check the petri dishes. Make sure seeds are separated and moist, but not standing in water.
  4. Place all seeds under intense fluorescent light for the duration of the investigation.
  5. Seeds should germinate in 2 to 3 days.
  6. Remind students to observe the seedlings carefully. They need to look at stem and leaf color. Color may change in intensity over time.
Seed Stock (Item Number) Genotype Phenotype Notes
Purple Stem, Hair (158810)
purple stem, sometimes extending to midribs of leaves; color varies from purple to dark pink
hair trait is quantitative and therefore best ignored in introductory activities
Non-Purple Stem, Hairless (158818)
anl/anl (recessive)
green stem
cross with 158810 for a monohybrid F1
Yellow-Green Leaf (158843)
ygr/ygr (recessive)
yellow-green leaves, purple stems
cross with 158810 for a monohybrid F1, or with 158812 for a dihybrid F1
Non-Purple Stem, Yellow-Green Leaf (158843)
anl/anl, ygr/ygr (double recessive)
yellow-green leaves, green stems
cross with 158810 for a dihybrid F1
Rosette-Dwarf (158815)
ros/ros (recessive)
very short plant
internodes do not elongate
Tall Plant (158825)
ein/ein (recessive)
tall, spindly plant
abnormally tall due to elongation of internodes
Petite (15833)
dwf1/dwf1 (recessive)
reduced height
mature at 5-15 cm; normal is 17-20+
Variegated (158820)
Var (non-Mendelian)
irregular leaf areas are devoid of chlorophyll
trait is part of the chloroplast genome, which is transmitted through the cytoplasm of the ovule; trait is not transmitted by pollen


Record the number of seeds germinated each day for 4 or 5 days, or as your teacher instructs. Identify the color of the stem and the color of the leaves for each seed germinated.

Day Number of Seeds Germinated Purple Stems Green Stems Green Leaves Yellow-Green Leaves

Data will vary by group depending on the mixture of seeds they selected.

Analysis & Discussion

  1. What are the 2 possible stem phenotypes?

    Purple, hairy
    Non-purple, hairless

  2. What are the 2 possible leaf phenotypes?

    Yellow-green leaves and green leaves

  3. Given your data, which phenotype appears to be dominant? Why?

    Answers may vary depending on data, but purple, hairy is the dominant stem color and green leaf is the dominant leaf color.

  4. How could you determine if a phenotype is inherited?

    Cross a green stem plant with another green stem plant. Harvest and plant the seeds. If the plants that grow from the seeds have green stems, the phenotype is inherited. If some plants have purple stems, the green stem phenotype may not be inherited, and more study is needed.

  5. Using the genotypes provided by your teacher, perform a dihybrid homozygous cross for purple stem color and green leaves with green stem color and yellow-green leaves. What are the phenotypes of the F1 generation?

    F1 are all purple stem and green leaf, heterozygous.

    ANL-YGR/ANL-YGR × anl-ygr/anl-ygr


Shop the Kit

Wisconsin Fast Plants® 72-Hour Dihybrid Genetics Kit


Helpful Links

*Next Generation Science Standards® is a registered trademark of Achieve. Neither Achieve nor the lead states and partners that developed the Next Generation Science Standards were involved in the production of, and do not endorse, these products.

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