Chapter 20, Problem 21P

Summary Introduction

To analyze:

The characters of normal Teosinte plant are unbranched, the same branch has female and male flowers, hard glume, and kernels. Maize has exactly opposite characters such as it is branched, has male inflorescence on its central branch, and female inflorescences on axillary branches. In addition, it has rows of kernels and soft glumes. A cross between cultivated maize and wild teosinte results in fully fertile ${\text{F}}_1$ plants. When self-fertilization is allowed in $\text{F1}$ generation plants, $1$ plant in every $1000$ of the ${\text{F}}_2$ generation is identical to either normal teosinte plant or cultivated maize. Question is asked to make a conclusion about whether the changes with a small effect in many genes or changes with a large effect in just a few genes is responsible for the variations in architecture of maize and teosinte.

Introduction:

Since plants and animals have evolved from a common unicellular ancestor, multicellularity in plants and animals has evolved independently. The cell wall encases the plant cell and necessarily restricts them in the location of origin. The organs that are generated by pluripotent cells are added to the plants throughout their lifetime. Since plants are immobile, they need to change their developmental program according to environmental changes. So, plants with identical genotype may show variations according to the surrounding environment.