In Jimson weed, the allele that produces violet petal is dominant over that for white petals, and the allele?

that produces prickly capsules is dominant over that for smooth capsules. A plant with white petals and prickly capsules is crossed with one that had vilet petals and smooth capsules. The F 1 generation was composed of 47 plants with white petals and smooth capsules, 50plants with violet petals and prickly capsules, 46 plants with violet petals and smooth capsules. What were the genotypes of the parents?

In Jimson weed, the allele that produces violet petal is dominant over that for white petals, and the allele?
These types of questions are quite simple actually. If you look carefully, you have progenies which are double recessive (white petals + smooth capsules). For you to get double recessive progenies, both parents cannot have any DOMINANT HOMOZYGOUS allele combination, ie. either violet homozygous or prickly homozygous.





Hence the genotypes of the parents should be white(homozygous)prickly(heterozygous), and violet(heterozygous)smooth(homozygous).





(In case you don't get it, detailed working below)


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Assume that V is allele for purple petals, v is allele for white petals, P is allele for prickly capsules, and p is allele for smooth capsule.





Writing out propable genotypes of parents:


white petals + prickly capsules = vvPP or vvPp


violet petals + smooth capsules = VVpp or Vvpp





Writing out the propable genotypes of F1 generation:


white petals + smooth capsules = vvpp


violet petals + prickly capsules = VVPP or VvPP or VVPp or VvPp


violet petals + smooth capsules = VVpp or Vvpp





If you do your punnet squares for the different parent genotype combinations, you would realise that for there to be progenies of vvpp, the parents cannot have any dominant homozygous allele combination in their genotype, i.e. the vvPP and VVpp combinations.





So the genotypes of the parents can only be vvPp and Vvpp.
Reply:well the genetics of a plant are like in humans-some dominant some recessive genes. so colour is dominant over no-colour but xx xy yx yy wd be the combination fter fertilisation-v dominant dominant mixed violet and white petals and pure whit being the yy gene mix ok
Reply:you are so going to flunk that test...........