Most commercially grown potatoes are either the round, smooth-skinned white eastern types used for potato chips and boiling or the russetted western types used for baking and french fries. Russet types have a rough skin and are larger and longer and have a higher dry matter content and growing season than eastern types. Many more potato types than this are popular in South American markets where tubers may be round, oval, elliptical, long, oblong, or blunt in shape. In cross-section they may be round or flat. The skin can be white, cream, buff, red, purple, or yellow in color and smooth, flaky, netted or russetted in texture.
Flesh can also be white, cream, buff, purple or yellow in color.
F. The optimal temperature for shoot emergence is 72 degrees F. Tuber initiation. Best initiation is under cool, moist conditions. Under high temperatures or dry conditions the rhizome continues to elongate without tuberizing. Above 68 degrees F night temperatures, initiation is reduced and above 84 degrees F, it is inhibited. High nitrogen and low light, or shortage of photosynthates, also inhibit initiation.