A true-breeding tall, red flowering plant is (TTRR) is crossed with a true-breeding dwarf, white plant (ttrr). What are the phenotypes in F2?

I know at the F1 TtRr x 4...then what? I know there is a 9:3:3:1 formula but I just can't memorize when to use it, I'd rather "foil" and get them myself.

All help is appreciated, thank you.

The F2 generation will be 9 Tall red, 3 dwarf red, 3 tall white, and 1 dwarf white.

You use this "formula" when you do a dihybrid cross (such as the one in the example). Since tall red is dominant, you'll have the most tall red plants and since dwarf white is recessive, you'll have the least dwarf white plants. The other two are just combinations of the characteristics.

If you'd rather foil, then just set up a punnet square with 16 slots and assign 2 characteristics per slot. For example, TR, Tr, tR, tr will be the four characteristics you will cross. While effective, this may take too much time so I sugget understanding the 9:3:3:1 phenotypic ratio.

The F2 generation will be 9 Tall red, 3 dwarf red, 3 tall white, and 1 dwarf white.

You use this "formula" when you do a dihybrid cross (such as the one in the example). Since tall red is dominant, you'll have the most tall red plants and since dwarf white is recessive, you'll have the least dwarf white plants. The other two are just combinations of the characteristics.

If you'd rather foil, then just set up a punnet square with 16 slots and assign 2 characteristics per slot. For example, TR, Tr, tR, tr will be the four characteristics you will cross. While effective, this may take too much time so I sugget understanding the 9:3:3:1 phenotypic ratio.

Thank you for explaining both. See, I am very scared I will somehow forget the 9:3:3:1. Thanks for the explanation (much better than Kaplan) and thanks for the foiling, I couldn't figure which ones to do. Thanks

Not a problem...good luck! :)