Somaclonal variation in tuber disc-derived populations of potato. II. Differential effect of genotype.

Three somaclonal populations of potato (Solanum tuberosum L.), each comprised of at least 1,000 plants, were regenerated from the cultivars Kennebec, Russet Burbank, and Superior. The frequency of formation of adventitious meristems from tuber disc explants varied significantly between these potato genotypes. Only 1.0-1.3% of each somaclonal population exhibited morphological aberrations. Regenerated populations of 'Kennebec' and 'Superior', when compared to respective control populations over three asexual generations, were similarly enriched with somaclones having more elongated tubers, a higher total tuber number and weight, a higher cull tuber number and weight, and earlier maturity. Somaclones of 'Russet Burbank' also produced more elongated tubers, a higher total tuber number, and a higher cull tuber number and weight but, in contrast, these somaclones were lower in total tuber weight, lower in U.S. 1 tuber number and weight, shorter in stem length, and lower in vigor. Of the three cultivars, 'Russet Burbank' somaclones possessed the greatest variability for most traits. Besides this significant genotype effect, quantitative traits differed amongst each other in respect of relative changes resulting from somaclonal variation. Observed differences among genotypes and quantitative traits will undoubtedly affect the success or failure of plant improvement programs attempting to utilize somaclonal variation.