Already at this early stage in common Indo-European language there are terms denoting rye, grain, grain, flax, barley, wheat, winnow, etc. Archeology has data that suggest that the rudiments of agriculture appeared (in the form of gathering and processing cereals) even 30—40 millennia ago in the era of the Young Sheksna interstadial, as evidenced by the numerous finds of stone pesto sources in Eastern Europe. It can be assumed that the wild ancestors of cereals such as rye, barley, oats, wheat and the most ancient Indo-European fiber-flax, being plants of long daylight hours, should have been initially spread exactly where there were the most favorable conditions for their natural existence.
So, in spring, long daylight plants need at least 14—16 hours of light for germination, and at least 16—18 hours for growth and development. But here it is appropriate to recall that, starting from 7th etc. and until the middle of 1 thousand 4 BC the climate of Eastern Europe was much warmer than modern, and spring came in the north 30—40 days earlier. With such a shift, the southern border of the range of these plants was 58—64° N.
L. S. Berg also noted that long-daylight cereals need long-term sunlight for earning, and in the north and east they have «relatively more favorable conditions than in the south and west… In the north, the absence of overheating is positive for plants from direct rays of the sun and a significant amount of scattered light.» And the huge amount of scattered light received by the territories of the East European North is evidenced by the following data cited by L. S. Berg:" Here (at 68° N) ultraviolet rays, contribute to the formation of vitamin, almost twice as much as under the 47—54° N, the intensity of ultraviolet radiation is much greater than in the middle latitudes».
Once again, the Eastern European localization of the Indo-European ancestral home was proposed in the middle of our century by A. Scherer, who believed that the areas occupied by the Indo-Europeans should border the area of the Pra-Ugrians, and after the collapse of the Indo-European community, the territory of Eastern Europe for a long time remained the habitat of various Indo-European tribes: Germans, and the Italians occupied the north and northwest; Balto-Slavs-northeast, and protogreek – southeast.