Question

heterozygous round and yellow seeded pea plants were selfed and total 800 seeds are collected. what is the total number of seeds with 1st dominant and 2nd recessive traits?

Answer 1

As per I could make out from your problem, 1st dominant and 2nd recessive gives the gene type as RRyy.

R for round dominant trait.

y for yellow recessive trait.

RRyy forms, are 1/16 ratio among 16 genotypes obtained in dihybrid cross.

So, very clear among 800, it will be 800/16 = 50

So, here is that, for what you are waiting the 50 as number of RRyy genotypes among 800 results.

Answer 2

Answer:

Since out of 16 seeds 3 are round-yellow, therefore out of 800 seeds total number of round yellow seeds =800* 3 16 =150

Explanation:

Solution 150

In Mendel's dihybrid cross, the ratio of different phenotypic traits obtained by selfing the pea plants of character heterozygous round yellow seeds is as follows.

Round yellow: Round - green : Wrinkled-yellow: Wrinkled-green

9 : 3 : 3 : 1

Here first dominant and second recessive means round - yellow seeds.

Since out of 16 3 are yellowish round, therefore out of 800 seeds

Total numer of round yellowish seeds = 800×( 3/16) = 150