---
title: "Task 3"
canonical: "https://wiki.groenkennisnet.nl/space/GB/12288051/Task%203"
format: markdown
---
**Creation of mapping populations** **(read Supplementary information 7.1.1 and 7.2.1.)**

For mapping we need a population, composed of plants from the same genetic background, that segregates for bitter and sweet plants. Such a population can be used to determine the genes underlying the trait. To develop such a mapping population crossing “bitter” and a “sweet” quinoa line is required to obtain a F1 hybrid.

To obtain true hybrids, with alleles of both parents combined, we have to prevent self-pollination. In several crops emasculation (removal of the pollen/stamen of the female parent) is performed to prevent self-pollination. However, due to the abundance of small flowers, manual emasculation has proven very difficult in Quinoa.

Two crosses were made between a bitter and a sweet Quinoa line. The seeds that develop on the female parent are the F1 seeds: Atlas (sweet) x Carina Red (bitter) and 0654 (bitter) x Kurmi (sweet)

  


**Read section 7.2.1. plant material**.

- Q: Describe how the cross **Atlas (sweet) x Carina Red (bitter**) was made and how first generation **true F1s** were identified
- Q: How were the true F1 hybrids selected in this case?
- Q: How many of the offspring proved to be from a real cross?

  


Phenotyping is done on seed tissue. Saponins taste bitter and can cause foaming in aqueous solution (see figure of foaming test).

![image](media://5421c00d-b80c-4256-b1e2-4df91ae59c44)

The F1 population is 100% heterozygous. A few of the **true F1 plants** were then selected to produce F2 seeds (by self-pollination) and one of these F2 families was selected as the <u>mapping population</u> (742 F2-plants).  
  


- Q: What is the segregation rate of  “sweet” compared to “bitter” in the this F2 population and how was this determined?
- Q: Is the sweet trait determined by a recessive or dominant gene? Explain.
- Q: Are sweet plants homozygous or heterozygous for the sweet trait?