Question

3. In a true breeding cross between two orchids, one with pink flowers, and the other with blue flowers, results in all pink-flowered orchids in the next generation. These pink-flowered orchids are allowed to self-pollinate and seed is collected. The seed is planted and the when the resulting plants flower, we observe 38 pink, 10 blue and 2 red-flowered plants. Please explain how flower color is determined in this orchid species while providing the genotypes of P, F1, and F2 generations. Please validate your hypothesis using chi square test. (8 points)

Answer 1

A True breeding of pink flower is crossed with blue flower and resulting all pink flowered Orchids in next generation it indicates pink flower (P) is dominant of blue flower (p). Pp x Pp Fa generation PP xPP Parental .. Pink Blycowego generati flower / 1 P gametes P P P FR gametes r & PP — I PR T PP PP othesis Pp (pink flower) pink flowes pink flowers Fa generation The phenotypic ratio of For will be: Pink flower Blue flower Pink flower : Blue flower null 3 : 1 - Phenotype Observed Expected (o-e) 110- Chi square Pink 38 50x3 = 37.5 (38-37.5 0.5)? flower = 0.5 0.25 0.0067 0.5067 flower 10 50x3 =12.5 (10-12.5) (-2.512 1 =-2.5 2 0.5 6.25 @ flower 50x0 = 0 (2-0)-2 (2)2 =4 undefined Blue Red are Degree of freedom (df) = (-1)=2 [df = no. of observed -17 Observed X value = 0·5067 L Xoor (5.99) The null hypothesis is accepted at 54. level of significance.