Question

2a) You try to create a hybrid between cauliflower (2n-18) and Chinese cabbage (2n - 20). and it works! However, your hybrid is not fertile. Briefly explain why. I 25) You still keep producing the cauliflower - chinese cabbage hybrids because they're so delicious. To your surprise, one of your plants appears to produce offspring through self- fertilization. What do you think happened, and how many chromosomes do the plants in the F2 generation have?

Answer 1

2a. The number of chromosomes that the sterile hybrid will received from cauliflower is 9 and from Chinese cabbage is 10. So, the total number of chromosomes in this hybrid will be 19 which is an odd number. Odd number polyploids are always sterile because they can not undergo chromosome pairing during gamete formation during meiosis.

2b. The fertile offspring which was there in the population has been developed due to chromosome doubling in the sterile hybrid. Chromosome doubling has occurred in the sterile hybrid having 19 chromosomes and after doubling it had 38 chromosomes. 38 chromosomes compare with each other forming 19 pairs during your space and thereby giving rise to gamete. Chromosome doubling occurs in nature all the frequency is very less. In laboratory, it is done by using a chemical called as colchicine.

Please rate high.