The Experimental Setup
Understanding Mendel's choice of traits and methodology
Why Pea Plants?
Mendel chose the pea plant Pisum Sativum for several important reasons:
- Easily differentiable traits - Clear visible differences between varieties
- Short growth period - Quick results for experimental cycles
- Self-pollinating - Easy to control breeding
- Large number of offspring - Statistical significance
Mendel's systematic experimental garden
The Seven Pairs of Traits
Mendel carefully selected 7 pairs of traits for his experiments. For each of these 14 traits, he obtained pure-bred varieties—varieties which don't show any variation in their offspring for several generations. He called this the Parental generation.
Plant height varies dramatically
Tall
Short
Vibrant purple vs pure white flowers
Purple
White
Smooth round vs angular wrinkled
Round
Wrinkled
Cotyledon color inside the seed
Yellow
Green
Smooth inflated vs pinched pods
Inflated
Constricted
Pod wall coloration
Green
Yellow
Flowers along stem vs at tips
Axial
Terminal
Mendel's Scientific Approach
Controlled Experiments
Used pure-bred lines to ensure genetic consistency before crossing
Statistical Analysis
First to apply mathematical methods to biological research
Reproducible Results
Repeated experiments across multiple generations for validation
Now we will run experiments to obtain the first generation of hybrids from this parental generation.