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23/09/2020 5:23 pm
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Grain colour in wheat is determined by three pairs of polygene. Following the cross AABBCC (dark colour) × aabbcc (light colour), in F2 generation what proportion of the progeny is likely to resemble either parent?
(a) Half
(b) Less than 5 percent
(c) One third
(d) None of these
1 Answer
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23/09/2020 5:45 pm
(b) Less than 5 percent
Explanation:
The F2 generation will show the intermediate colour because of quantitative inheritence. In case of crossing between AA BB CC (dark colour) and aa bb cc (light colour), in F2 generation seven phenotypes will be obtained with ratio 1 : 6 : 15 : 20 : 15 : 6 : 1. The total number of progeny is 64, out of which only two will be likely resemble with either parents. Hence, their percentage in F2 generation would be 3.12 i.e less than 5%.