Relative Performance of Potato Cultivars in Short Rotations

Abstract

In the crop rotation experiments at ‘De Schreef’ and ‘PAGV yield losses were obtained with increased frequency of potato cropping. To examine the influence of fungal pathogens, several potato cultivars were used from 1981 to 1983: cultivars tolerant to Verticillium dahliae and immune to the Streptomyces spp. that cause netted scab (I), cultivars intolerant to V. dahliae and immune to Streptomyces spp. (II) and cultivars intolerant to V. dahliae and susceptible to Streptomyces spp. (III). In the experiment at De Schreef the yield losses of the cultivars in groups I, II and III in three-course (potatoes cropped once in 3 years) crop rotations versus six-course (once in 6 years) crop rotations were 3%, 8% and 10%, respectively, averaged over 1981 and 1982. The corresponding figures for 1983 were only 2%, 3% and 5%, respectively. At the PAGV experimental site the yield losses in continuous cropping versus a six-course rotation were 14% for group I (cultivar Mirka) and 34% for group II (cultivar Saturna) averaged over 1981 and 1982. The corresponding figures for 1983 were approximately 0% and 33%, respectively.

Based on cultivar reaction and observations of the incidence of several diseases, it is concluded that V. dahliae was the most important yield-reducing pathogen in short rotations. However, for the experiment at De Schreef, when the cultivar Bintje, which is susceptible to netted scab, was grown, netted scab contributed to the yield depression.