samiam99 Posted May 19, 2011 Share Posted May 19, 2011 (edited) Punnet square question? True breeding punnet square? I got the right answer but need some clearing up. true-breeding dwarf and true breeding maize plants produced all dwarf plants in F1 . in the f2 generation dwarf and tall plants segregated 3:1 ratio. Dwarf F2 plants self pollinated. what proportion of the resulting plants would be expected dwarf let BB=Dwarf bb=tall BBXbb F1= 1 Bb Bb x Bb F2=1 BB:2 Bb: 1bb now it gets tricky.. so there is a 1/3 chance that BB x BB but a 2/3 chance that Bb x Bb...what I am confused about is what about the chance Bb x BB? ......................................… if BB and BB were crosses all offspring would be BB(dwarf) 4/4=1 *1/3= 1/3 if Bb and Bb were crossed 3/4 would be dwarf so 3/4* 2/3=6/12+1/3= 10/12= 5/6 proportion expected to be dwarf? Edited May 19, 2011 by samiam99 Link to comment Share on other sites More sharing options...
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