Agrobiology, p. 134 (1954)
Sunflowers and Broom Rape
T. D. Lysenko

Not long ago, last winter, I insisted that Baransky (a sunflower specialist) should not sow inbred lines. It was already clear to me then that the breeding of sunflower could not be conducted by the inbreeding method. Baransky at that time agreed with me on many points regarding the problem of inbreeding, just as N. I. Vavilov does now. But for all that he insisted that the inbred material which last year occupied (and occupies this year) the major part of the sunflower breeding area (including hybrids of inbred lines) should also be sown in 1935. The weightiest argument he advanced was that in this inbred material there were many lines which (according to the data of past years) were resistant to broom rape. Knowing how enormously important resistance to broom rape is for sunflower, I could not forbid him to sow this material. True, my mind could not grasp why inbred lines, biologically enfeebled, degenerates, should become more resistant to broom rape. Facts, however, cannot always be disproved to the satisfaction of others or even one's own by mere argument. But what did we see yesterday when we inspected the sunflower breeding ground? Not a single inbred line that was "resistant to broom rape" before sowing showed the slightest sign of such resistance after sowing. In the majority of these "resistant lines" the broom rape grew higher than the sunflowers themselves. Next to them are the outbred Zhdanov varieties grown in the North Caucasus. These are powerfully developed and practically resistant to broom rape.

I would like to know why inbred lines that were “resistant” to broom rape before sowing turned out to be absolutely nonresistant after sowing.