Plant Cell, Tissue and Organ Culture 23: 181-186, 1990. © 1990 Kluwer Academic Publishers. Printed in the Netherlands. Genetical analysis of in vitro cell and tissue culture response in potato M. Coleman, R. Waugh & W. Powell* Cellular and Molecular Genetics Department, Scottish Crop Research Institute, Invergowrie, Dundee, Scotland DD2 5DA (*requests for offprints) Received 18 January 1990;acceptedin revised form 25 July 1990 Key words: heritability, protoplasts, RFLPs, Solanum tuberosum Abstract The genetics of tissue culture response in potato has been examined by analysing a sample of dihaploids 2n = 2x = 24) extracted from tetraploid parents (4n = 4x = 48). The genotypes were screened for rate of nodal multiplication, in vitro tuberisation, regeneration from leaf discs and protoplast plating efficiency. Significant differences were detected between dihaploids for the traits measured and this indicates that tissue culture response in the tetraploid parents must be in the heterozygous condition. Estimates of the broad sense heritabilities were calculated together with the number of genes or effective factors involved in the control of the traits. These estimates indicate that tissue culture response in potato is under relatively simple genetic control and "blocks of genes" may be located on specific chromosomes. The inheritance of RFLP markers in the segregating dihaploid population was also monitored and the potential of using molecular markers linked to gene(s) controlling tissue culture response is discussed. Introduction Regenerative cell and tissue culture systems pro- vide an important link between cellular and mole- cular approaches to crop improvement and whole plant biology. The successful utilisation of in vitro methods is dependent upon the development of reliable culture protocols which are applicable to commercially desirable genotypes. Unfortunately, plant regeneration from culture is genotype-depen- dent [4] and this often restricts the use of elite germplasm in transformation and protoplast fu- sion studies. The assessment of genotype response by stud- ying protoplast isolation and regeneration is a complex process which can take several months. A simple reliable screen for genotype response which could be correlated to more complex culture methods would be extremely useful. Tan et al. [1] found that the efficiency of shoot regeneration from leaf discs of tomato genotypes was indicative of shoot regeneration from proto- plasts while Fish & Jones [2] using potato mat- erial found similar results. However, in the potato study the genotypes used had been selected for disease resistance. Any conclusion made by the authors will therefore be confounded by previous selection. In order to extend the work of Fish & Jones [2] we have examined tissue culture res- ponse in a random sample of dihaploid potato genotypes extracted from tetraploid parental cul- tivars. Four tissue culture methods have been evaluated in potato to investigate the genetical basis of culture response. The tissue culture systems included: rate of nodal multiplication, microtuber production, adventitious regeneration from leaf pieces and protoplast division/colony formation and allowed the extent and nature of the genetic variability to be quantified. The dihaploid and parental populations were also the subject of Restriction Fragment Length Polymorphism (RFLP) analysis to demonstrate the potential of correlating RFLP profiles with tissue culture response.