It’s commonly believed that the nectarine is a hybrid of a peach and plum. This is actually not true at all, although they are both technically from the same family- the rose family. Ripe fruit should yield to gentle pressure, particularly along the seam, though it should be somewhat firmer than a ripe peach. A ripe nectarine has a sweet fragrance, and smell as much as feel should be used to determine good, ripe fruit. Once picked, nectarines will not get sweeter but will become softer and juicier. Avoid fruit that is rock-hard, green, mushy or has shriveled skin. In general, nectarines are slightly smaller and sweeter than peaches.