In heaven, the water is 'pure':
Rev_22:1 And he shewed me a pure river of water of life, clear as crystal, proceeding out of the throne of God and of the Lamb.
Fruits are borne upon trees, which drink up the 'pure' water, and thus bare 'pure' fruit:
Rev 22:2 In the midst of the street of it, and on either side of the river, was there the tree of life, which bare twelve manner of fruits, and yielded her fruit every month: and the leaves of the tree were for the healing of the nations.
There is no genetic degradation in Heaven, as it is perfect, being that there is no sin there, as it was in the beginning in Genesis (Genesis 2:1, "finished', 'perfected', 'brought to perfect completion'). In the sanctuary God told the Israelites to make the Golden Candlestick of 'pure' gold, and the candlestick is a 7 branch tree (6 branches & 1 central), which bears its fruit on it with flowers and knops. One can also consider the pomegranates upon the Hem of the High Priest, who is to represent Jesus the Tree, and upon the pure tree, is the pure fruit. One may also consider the pure trees the lined the walls of the sanctuary also, as representative of Heaven. God's work is 'pure', and can only accept a 'pure' offering and in tithe.
Kind was to bring forth after their kind. Yet due to sin, the fall of man, the curses (plural) upon this earth, and man's manipulation, and the devil's manipulation (GMO, gainsayers modified orders), they have lost a lot of purity (as it was in Genesis 4-6 and so also too even now).
There are other ways to show this also, but this should suffice for those interested in the subject that they may go and look for themselves.