A survey of potato (Solanum tuberosum L.) plant stands in upstate New York over a three-year period showed that the average distance between plants was 4 cm wider than intended. Plant stands averaged 83%. The failure to plant seed pieces was the major reason for missing hills. Seed rot was not generally a problem, although one field in the survey was severely affected. Speed of planting up to 6.7 km/h had no consistent effect on average spacing or uniformity of seed piece distribution. Seed type (whole or cut) and mechanical condition of planter influenced spacing. Experiments conducted over four years indicated that the non-uniform seed piece distribution delivered by commercial picker-arm planters does not adversely affect crop yield or tuber size. Non-uniform seed distribution with extremely high coefficients of variation (greater than 100%), however, affected yield, tuber size and tuber number.

Verticillium wilt disease of potato is caused predominantly by Verticillium albo-atrum andV. dahliae. StVe1 —a putative QTL for resistance against V. dahliae —was previously mapped to potato chromosome 9. To develop allele-specific, SNP-based markers within the locus, the StVe1 fragment from a set of 30 North American potato cultivars was analyzed. Three distinct and highly diverse haplotypes can be distinguished at the StVe1 locus. These were detected in 97%, 33%, and 10% of the cultivars analyzed. We tested for haplotype association and for genetic linkage between the StVe1 haplotypes and resistance of tetraploid potato to V. albo-atrum. Moreover, field resistance was assessed in diploid populations with known molecular linkage maps in order to identify novel QTLs. Resistance QTLs against V. albo-atrum were detected on four chromosomes (2, 6, 9, and 12) at the diploid level, with one QTL on chromosome 2 contributing over 40% to the total phenotypic variation of the trait. At the tetraploid level, a significant association between the StVe1-839-C haplotype and susceptibility to the disease was detected, suggesting that resistance-related genes directed against V. albo-atrum and V. dahliae are located in the same genomic region of chromosome 9. However, on the basis of the present analysis, we cannot determine whether these genes are closely linked or if a single gene provides resistance against both Verticilliumspecies. To assess the usefulness of theStVe1-839-C haplotype for marker-assisted selection, we subjected the resistance data to Bayesian analysis, and calculated positive (0.65) and negative (0.75) predictive values, and overall predictive accuracy (0.72). Our results indicate that tagging of additional genes for resistance to Verticillium with molecular markers will be required for efficient marker-assisted selection.

DNA‐based genetic markers are now widely used by geneticists to locate genes for quantitative traits, and may also serve as a valuable tool for dissecting complex physiological phenomena. Van den Berg et al. (1996a QTL analysis of potato tuberization. Theor Appl Gen 93: 307–316), using restriction fragment length polymorphism (RFLP)‐mapped populations of potato, detected eleven quantitative trait loci (QTLs) for tuberization. Taylor et al. (1992 Expression and sequence analysis of cDNAs induced during the early stages of tuberisation in different organs of the potato plant [Solanum tuberosum L.]. Plant Mol Biol 20: 641–651) have identified one of the genes associated with tuberization as that for the enzyme S‐adenosylmethionine decarboxylase (SAMdc), an enzyme of the polyamine biosynthetic pathway. Chromosomal loci for SAMdc and arginine decarboxylase were established on the potato and tomato chromosomal maps, respectively, by hybridizing cDNA probes for these genes to RFLP digests. The polyamine content of leaves from an RFLP‐mapped potato population was analyzed by fluorescence detection following HPLC, with quantitation using an internal standard. The data were analyzed by the ‘qGene’ statistical program, and QTLs for polyamines were detected on seven chromosomes. At least six QTLs were found for spermine, two for spermidine, and two for putrescine. A spermidine QTL was on chromosome 5 linked to marker TG441, very close to the place where SAMdc mapped. There was some congruence between QTLs for spermine and those previously detected for tuberization and dormancy, but relationships were not consistent.

Cell division and cell expansion during early stages of tuber tuber development were studied using developing axillary buds on single-leaf cuttings from potato (Solanum tuberosum L.). Cuttings taken from plants induced to form tubers, by short day (SD) treatment, were compared with cuttings from non-induced (long day, LD) plants. In the apical zone of the buds, cell division occurred From the first day after cutting, in both LD and SD cuttings. The planes of these divisions were transverse, associated with elongation of the buds. At day 5, a new orientation of cell division was observed in the subapical zone of SD cuttings only. These divisions were longitudinal, associated with radial growth. Cell expansion occurred in both SD and LD cuttings, and was not uniquely related to the onset of tuber formation. (C) 1999 Annals of Botany Company.

In previous studies polygene mapping of a backcross population derived from haploid potato (Solanum tuberosum) and a diploid wild species (Solanum berthaultii) showed at least eight quantitative trait loci (QTLs) associated with tuber dormancy. The same population was mapped for abscisic acid (ABA) content in tubers so that any QTLs identified could be compared with those detected previously. At least three distinct loci on three chromosomes (2, 4, and 7) were associated with variation in ABA content. One of the QTLs was detected only as a main (single locus) effect, and two QTLs were found through two-locus interaction analysis (epistasis). Interaction between QTLs at markers TG234 (chromosome 2) and TG155 (chromosome 4) explained 20% of total phenotypic variance for this trait. The interaction closely resembled one previously detected for dormancy, suggesting an association between high ABA content and long tuber dormancy. Although relationships between ABA level and dormancy could be demonstrated through polygene mapping, there was no indication of a relationship between these traits when they were subjected to a conventional correlation test. This illustrates the usefulness of polygene mapping as a tool to identify possible associations between hormone levels and plant development.

Quantitative trait loci (QTLs) affecting tuberization were detected in reciprocal backcrosses between Solanum tuberosum and S. berthaultii. Linkage analyses were performed between traits and RFLP alleles segregating from both the hybrid and the recurrent parent using a set of framework markers from the potato map. Eleven distinct loci on seven chromosomes were associated with variation in tuberization. Most of the loci had small effects, but a QTL explaining 27% of the variance was found on chromosome 5. More QTLs were detected while following alleles segregating from the recurrent S. tuberosum parent used to make the backcross than were detected by following alleles segregating from the hybrid parent. More than half of the alleles favoring tuberization were at least partly dominant. Tuberization was favored by an allele from S. berthaultii at 3 of the 5 QTLs detected by segregation from the hybrid parent. The additive effects of the QTLs for tuberization explained up to 53% of the phenotypic variance, and inclusion of epistatic effects increased this figure to 60%. The most common form of epistasis was that in which presence of an allele at each of 2 loci favoring tuberization was no more effective than the presence of a favorable allele at 1 of the 2 loci. The QTLs detected for tuberization traits are discussed in relationship to those previously detected for trichome-mediated insect resistance derived from the unadapted wild species.

Tuberonic acid glucoside and tuberonic acid glucoside Me ester were detected in the leaves of Solanum tuberosum. This is the first report of the isolation of the latter from potatoes. Higher concentrations of both substances were detected in leaves of plants grown under long than under short days. Methylation of tuberonic acid glucoside prior to GC-mass spectrometry increased the threshold for detection 12–50-fold, depending upon whether Ac or TMSi derivatives were made.

The objective of this research was to purify the protein that binds and reduces the activity of potato (Solanum tuberosum L.) tuber acid invertase. Our attempt to isolate invertase inhibitor from potatoes (cv. Katahdin) using previously published procedures resulted in the inhibitor co-purifying with several other proteins without inhibitor function, of similar weight but different pI values. These impurities were obscured on SDS-PAGE discontinuous polyacrylamide gels since after the first purification step all the proteins had molecular weights ranging from 17 to 18 kDa. Using a glycerol-propyl silane (GPS-) modified silica column in combination with a Tricine buffer, a single protein band was identified as the inhibitor on IEF-PAGE gels. The inhibitor was identified as a protein that has a mol. wt of approximately 17 and a pI of 5.1.

Potato tuberization is promoted by short days and inhibited by applications of gibberellin (GA). Wildtype Solanum tuberosum ssp. andigena required short days for tuberization, whereas their dwarf siblings tuberized under long days. Nevertheless, shortening the photoperiod also enhanced tuberization of dwarf plants and caused an increase in leaf angle and a reduction in internode length of both genotypes. The potential role of GA metabolism in tuberization as influenced by dwarfing and photoperiod was investigated by studying the metabolism of [14C]GA12 in shoots of wild-type and dwarf potato plants. Measurement of metabolite levels was by radiocounting after HPLC. The data indicated a reduced conversion of GA12 to GA53 in dwarf plants, a difference which may be responsible for the dwarf morphology, although other explanations cannot be ruled out. Dwarf plants contained much less GA1, as measured by GC-MS. We did not detect differences in [14C]GA12 metabolism between plants grown under 10-h versus 16-h photoperiods, in either wild-type or dwarf plants, even though other wild-type plants contained less GA1, under short photoperiods than under long photoperiods.

Metabolism of [14C] gibberellin(GA)12-aldehyde and [14C]GA12 in vegetative tissue of potato (Solanum tuberosum ssp. andigena) was studied by supplying solutions of these compounds to the base of isolated shoot tips and analyzing the metabolic products by radiodetection after HPLC. Endogenous gibberellins that co-eluted with the 14C-metabolites on HPLC were identified by GC-MS as GA53-aldehyde, GA53, GA44, GA19, GA20, GA29, GA1, and GA8. Thus the early-13-hydroxylation pathway seems to be a major pathway in vegetative potato shoots. This was confirmed by time-course feeding studies; according to HPLC elution profiles, the members of the pathway were produced from [14C]GA12-aldehyde and [14C]GA12 in the expected time sequence. The formation of GA53 appeared to be predominantly via GA12 rather than GA53-aldehyde. The detection of endogenous GA51 suggests that the non-hydroxylation pathway was also active. Comparisons of HPLC retention times of radioactive metabolites before base hydrolysis with retention times after base hydrolysis showed that potato shoots can conjugate several GAs. HPLC retention times of other radioactive metabolites corresponded with previously published retention times of GA29-catabolite, GA51-catabolite, GA12-aldehyde-conjugate, and GA53-aldehyde-conjugate.

This chapter contains sections titled: Introduction Methods of Studying Tuberization Environmental Factors Affecting Tuberization Genetic Effects Effects of the Mother Tuber Physiological Nature of Induction to Tuberize Changes in the Stolon Tip or Bud Associated with Tuberization Patterns of Stolon and Tuber Formation Resorption and Second Growth Implications for Tuber Yield Conclusion Literature Cited

Tuberization and stolonization of cuttings were used as a model system to assess response to photoperiod in segregating potato progenies. The progenies were from backcrosses of a diploid hybrid between Solanum tuberosum and the short day requiring S. berthaultii to both parent species. Restriction Fragment Length Polymorphism (RFLP) analyses had been performed on these progenies as a part of other investigations. The RFLP maps were used to identify the loci controlling the photoperiod responses characterized by the cuttings. In the S. berthaultii backcross population, one locus appeared to control the response of cuttings only under long photoperiods, and coincided with a locus detected for stolonization on whole plants; a second locus was effective for tuberization under short photoperiods but was not detected with certainty under long photoperiods. Data analysis for the second backcross population is currently underway.

Journal Article Starch Accumulation in Leaves of Potato (Solanum tuberosum L.) during the First 18 Days of Photoperiod Treatment Get access J. H. LORENZEN, J. H. LORENZEN * Department of Fruit and Vegetable Science, Cornell UniversityIthaca, New York 14853-0327, USA * Present address: Department of Horticulture and Forestry, North Dakota State University, Fargo, North Dakota 58105, USA. Search for other works by this author on: Oxford Academic PubMed Google Scholar E. E. EWING E. E. EWING Department of Fruit and Vegetable Science, Cornell UniversityIthaca, New York 14853-0327, USA Search for other works by this author on: Oxford Academic PubMed Google Scholar Annals of Botany, Volume 69, Issue 6, June 1992, Pages 481–485, https://doi.org/10.1093/oxfordjournals.aob.a088375 Published: 01 June 1992 Article history Accepted: 18 November 1991 Published: 01 June 1992 Received: 13 July 1992

The South American tetraploid potatoesSolanum tnberosum sspandigena have been used to increase the genetic variability of the temperate potatoS. tuberosum ssptnberosum. One technique that has been practiced for Andigena-based germ plasm enhancement has been to select within Andigena for adaptation to temperate conditions then to hybridize these selections with Tuberosum. This technique which is called pre-selection in this paper reduces the number of original accessions during selection resulting in loss of diversity of the enhanced germ plasm. This technique was compared to an alternative one called early hybridization, which consisted of hybridizing the Andigena introductions with Tuberosum, then practicing the same type of selection for adaptation on the hybrid population.