Question

State any four reasons why Mendel succeeded in his genetic hybridisation experiments on garden peas.

Hint:

Give any four reasons: pea is easy to grow, has clear contrasting traits, gives pure lines, allows controlled crossing, and results were counted statistically.

Answer 1

Step 1: Plant choice:
Mendel chose the garden pea (Pisum sativum). It is easy to grow, has a short life cycle and gives many seeds in each generation, so the results can be counted.

Step 2: Clear traits:
He chose seven pairs of easily visible, contrasting characters, such as tall and dwarf or round and wrinkled seeds. Each pair showed only two clear forms.

Step 3: Pure lines:
He first raised true-breeding (pure) lines by self pollination for several generations. This made sure that the parents were homozygous for the trait.

Step 4: Controlled crosses:
Pea flowers are bisexual and self pollinating, but he could emasculate them and pollinate by hand. This allowed him to make the exact cross he wanted.

Step 5: Counting:
He studied one or two traits at a time and counted the offspring of each type. He used mathematics (statistics) to analyse the ratios.

Final Answer:
Any four: contrasting traits, true-breeding lines, easy controlled crossing, many seeds, short life cycle, one trait at a time with counting.