History of walnut

Walnuts belong to the genus Juglans, of the walnut family Juglandacae. Ancestral forms of walnut once spanned Europe, Asia and the Americas as far as north as Alaska.

Climate changes altered the geographic distribution and further evolutionary pressures resulted in the 21 species of Juglans in existence today.

All species produce nuts but the Persian or English walnut (Juglans regia) is the only species widely cultivated for nut production. The name Persian walnut is descriptive of its origin. Since Roman times, the English walnut had been cultivated commercially in Europe.

The walnut tree was introduced into Europe by the Romans and has been grown there since the 4th century. The Greeks cultivate the tree intensively, mainly for walnut oil, and the Romans regarded it as a sacred tree.

The word walnut may be derived from ‘wealh nut’, ‘wealh’ meaning foreign in Anglo-Saxon or old German. Trees of the species were in England by 1562 and nuts were brought to America by the earliest settlers.

The American colonist are said to have called the species ‘English’ walnut because it was brought to America on English ship and to distinguish it from the native American eastern black walnut (J. nigra). Black walnuts are native to the Central Mississippi Valley and the Appalachian region of North America. Black walnuts were an important source of food for the American Indians and early settlers.
History of walnut

History of Food Crops

History of Food Crops
The angiosperms provide most of our food crops. They first appeared in the early Mesozoic or late Paleozoic era about 200 – 250 million years ago, but fossil evidence of them is extremely limited until they began to dominate during the Cretaceous (136 – 190 million years ago). The angiosperms were the first plants to have double fertilization and the enclosure of seeds in fruit. Double fertilization provided zygotes with copious resource to help them get established and fruits attracted animals for dispersal, it was the appearance of the angiosperm that set the stage for the development our mammal ancestors.

A wide range of hypotheses implicating selection have been presented for a rapid emergence and diversification of the angiosperms. The most popular hypothesis is that the concomitant rise of pollinating insects led to powerful divergent selection as foragers and hosts developed complex relationship.

It was the angiosperms that ultimately provided us with most of our crops and their emergence predated the appearance of our species, Homo sapiens. In fact, most of our food families or their close relatives were in existence long before we began farming. The only completely new crop type to appear after the advent of agriculture was maize, Zea mays, which has an ear and tassel arrangement not found in its progenitors. In most cases, human beings did not influence the overall structure of crop species, only the size of their edible organs and their ease of harvest.

Human beings now consume a diverse array of plant structure, and at least 64 families of angiosperms and 180 genera are utilized as crops. This is a broad systematic group, but represents only a small fraction of the total number of angiosperm families (300) and genera (3000). The dicotyledons provide the highest number of crop plants; however, the bulk of the world is fed by a few monocotyledonous grains (maize, rice and wheat).
History of Food Crops