If I understand your question, you're saying both parents in the P generation are homozygous for round fruit shape and elongate stems. You want to know what the genotypes of the offspring (F1 generation) would be.
This is quite simple. If an organism is homozygous for a trait, it means that both alelles for that gene are the same. So if you used R for round and r for oval, the parents would be RR. The only gametes they can produce for that trait would be "R", so during fertilization, both parents contribute an "R", so the offspring would be "RR". The same for elongate. If elongate is the dominant trait (call it "EE") instead of short ("ee"), the only gamete that either parent could contribute would be an "E", so with the fertilization of the two gametes, the offspring would be "EE". So the genotype of the F1 generation would be RREE.
NOTE - the letters used and whether the traits are dominant or recessive (upper or lower case) will depend on the information in your problem. I just used the letters I did as an example.