*THESE 2 QUESTIONS ARE RELATED. IF THERES ANY WAY FOR ME TO AWARD MORE KARMA POI
ID: 15305 • Letter: #
Question
*THESE 2 QUESTIONS ARE RELATED. IF THERES ANY WAY FOR ME TO AWARD MORE KARMA POINTS, I WILL!!!
1) Pollen produced by a plant with the genotype S2S3 lands on the stigma of the plant with the genotype of S1S2. This species has a gametophytic genetic self- incompatibility system. What progeny will result?
A) S1S2, S2S2
B) S1S3, S2S3
C) S1S2, S1S3
D) S1S2, S2S2, S1S3, S2S3
E) None
2) In the previous question, what progeny will result if the species has a sporophytic genetic self- incompatibility system? Assume the S2 and S3 alleles are codominant in the tapetum
A) S1S2, S2S2
B) S1S3, S2S3
C) S1S2, S1S3
D) S1S2, S2S2, S1S3, S2S3
E) None
Explanation / Answer
answer is B) S1S3, S2S3 tape tum have a gametophytic self-incompatibility system. The incompatibility reaction is initiated by the genotype of the microgametophyte (pollen) interacting in the style with the genotype of the pod parent. Self-incompatibility genes are usually represented by a lower case "s" with subscripts to indicate the various alleles at the self-incompatibility locus. A pod parent of genotype s2s3 will inhibit the growth of pollen tubes carrying either the s2 or s3 alleles, and no seed will be produced. Thus, a cultivar of genotype s2s3 will not self pollinate or cross with another cultivar with genotype s2s3. A cultivar of genotype s1s2 will produce pollen grains of genotypes s1 and s2. Thus, in a cross of s2s3 x s1s2, the s3 pollen grains of the pollen parent will grow and fertilize the egg cells, but not the s2 pollen. The resulting progenies will be of genotypes s1s3 and s2s3. 2) C) S1S2, S1S3
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