. Bulletin. Natural history; Science. Dr. Beadle examines a primitive type of corn he has derived from a cross between teoslnte and classification of \he first large second- generation crop grown in Mexico. Wtiat have been the results? In the second-generation cross of Chapalote corn and Chaico teosinte we found good parent corn types and good parent teosinte types with a frequency of about 1 of each in 500 plants. These frequencies are intermediate between those expected with four and those expected with five gene differences. Of course, the genetic complexities are greater than this k
. Bulletin. Natural history; Science. Dr. Beadle examines a primitive type of corn he has derived from a cross between teoslnte and classification of \he first large second- generation crop grown in Mexico. Wtiat have been the results? In the second-generation cross of Chapalote corn and Chaico teosinte we found good parent corn types and good parent teosinte types with a frequency of about 1 of each in 500 plants. These frequencies are intermediate between those expected with four and those expected with five gene differences. Of course, the genetic complexities are greater than this kind of arithmetic implies, but I will not go into them here. Second-generation and backcross populations have been grown involving other races of both corn and teosinte. They show that the frequencies with which the parental corn and teosinte reappear may vary rather widely depending on the races involved. In response to doubts about whether the recovered corn ears were really "good" parental type corn expressed by Professor Paul C. Mangelsdorf, who has published very different ideas about the origin of corn, I devised a "cob ; Cobs from "pure" parent corn and cobs from my hybrid populations were coded and presented separately to Professor IVIangelsdorf and also to Professor Galinat for classification. Both of them judged enough cobs of hybrids to be those of good corn to reassure me, and I hope convince them, that "good" parental type corn is indeed recovered in reasonable frequencies in second-generation hybrids and in backcrosses of first-generation hybrids to corn. It seems clear that the genetic differences between corn and teosinte cannot be so great as to render untenable the hypothesis of an ancestral relationship of teosinte to corn. And it seems reasonable to assume that pre-Columbian man could have selected and preserved the relatively few mutants required to produce a useful plant from teosinte— primitive corn. Contradi
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