The Way of Science

2. Maize

In the west, hybrid corn (maize) had become a convincing demonstration of the power of Mendelian genetics. In brief, this kind of breeding program is based on intensive inbreeding (crossing an organism to itself, or to a very closely related individual). As you may know, this pattern ("incest") will frequently result in serious loss of offspring vigor, increased susceptibility to disease, etc. The inbreeding increases homozygosity: the occurrence of identical alleles paired together. The advantages of controlled and directed inbreeding are in producing pure lines, where no hidden recessives are lurking. One can now breed together two stunted, weak and miserable parents who are homozygous in different ways (AA vs. aa, for example) and generate a very heterozygous batch of seed which is not only equipped with hybrid vigor, but whose genes have been selected for producing uniform size of plants, time of crop production, amino acid concentrations, etc. Remember, though, that recombination will occur when these very vigorous hybrid plants reproduce, and the highly desirable genotype will re-assort. The next generation will be very non-uniform in all ways, and much less vigorous. The only way to produce such hybrids is to buy seed yearly from the specialists who have the stunted parents.

It was not difficult for Lysenko to denounce hybrid corn as another capitalist plot. Early trials in the USSR failed to produce high yields, primarily because of the old farming techniques still used by the peasantry. Growing hybrid corn requires, among other things, large quantities of fertilizer and water. In addition, Lysenko "demonstrated" that the plants lacked vigor. The tests he used, needless to say, had no validity, but the political audience was convinced.

Lysenko also claimed that "inbreeding was the cause of problems" (after all, it is incest). His solution was to plant huge numbers of different corn varieties, and allow "marriage of love in maize" (no kidding). He said that the plants would know what is best for the area, and choose mates accordingly.