can someone help me please In cucumbers, dull fruit (D) is dominant over glossy

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can someone help me please

In cucumbers, dull fruit (D) is dominant over glossy fruit (d), orange fruit (R) is dominant over cream fruit (r), and bitter cotyledons (B) are dominant over nonbitter cotyledons (b). The three characters are encoded by genes located on different pairs of chromosomes. A plant homozygous for dull, orange fruit and bitter cotyledons is crossed with a plant that has glossy, cream fruit and nonbitter cotyledons. The F_1 are intercrossed to produce the F_2. Give the expected proportion of offspring with a dull, orange, and bitter phenotype or a glossy, orange, and bitter phenotype in the F_2. 9/64 27/64 9/16 1/4 3/128

Explanation / Answer

Ans-a)

In cucumbers, dull fruit (D) is dominant over glossy fruit (d), orange fruit (R) is dominant

over cream fruit (r), and bitter cotyledons (B) are dominant over nonbitter cotyledons (b). The

genotype of F1 plants that have have dull, orange fruit and bitter cotyledons is DdRrBb. The

F1 are intercrossed to produce F2.An F1 plant is crossed with a plant that has glossy, cream

fruit and nonbitter cotyledons. F1 is intercrossing with a plant that has glossy, cream fruit,

and nonbitter cotyledons is a testcross.Therefore,all off spring will be expected in equal

proportions and phenotype of the offspring determined by the alleles of F1 parent.

             DdRrCc (F1) × ddrrcc (tester)

      F1 Locus 1 (Dd):      ½ D and ½ d

      F1 Locus 2 (Rr):       ½ R and ½ r

      F1 Locus 3 (Cc):      ½ C and ½ c

      dull, orange, bitter: ½ dull × ½ orange × ½ bitter = 9/64

      dull, orange, nonbitter: ½ dull × ½ orange × ½ nonbitter = 9/64

      glossy, orange, bitter: ½ glossy × ½ orange × ½ bitter = 9/64

      glossy, orange, nonbitter: ½ glossy × ½ orange × ½ nonbitter = 9/64

      glossy, cream, bitter: ½ glossy × ½ cream × ½ bitter = 9/64

      glossy, cream, nonbitter: ½ glossy × ½ cream × ½ nonbitter = 9/64

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