Farkas, J., 1974: Results of genetical studies in tomato. Zoldsegtermesztesi Kutato Intezet Bulletinje 9: 61-64
It has been found that the reduction in yield occasioned by homozygosity of the genes Tm1, Tm2 and Tm22 for resistance to tobacco mosaic virus (TMV) can be counteracted by hybrid vigour, an effect which has been exploited in the Kecskemet hybrid Rezisztens Hajtato F1 which is resistant to TMV, Verticillium wilt, Fusarium wilt and nematodes. The seedling anthocyanin gene ah has proved useful as a marker in hybrid seed production.