Elucidation of the evolution and taxonomy of cultivated potatoes with electrophoresis

Summary A recently developed polyacrylamide gel electrophoresis technique for tuber proteins is used to help elucidate the evolution and taxonomy of some cultivated potatoes. The results substantiate the theory that Group Tuberosum evolved from Group Andigena, that Group Andigena evolved from a cultivated diploid × wild diploid hybrid, and that Group Phureja evolved from Group Stenotomum. Furthermore, the results suggest these groups are closely enough related to merit classification within a single species.Scientific Journal Series Article 10,172 of the Minnesota Agricultural Experiment Station     

An assay for chromosomal and chromatid interference in chromosome V ofSaccharomyces

This survey included 1250 tetrads from 19 families heterozygous for at least three genes on chromosome V. A number of tests were used for the detection of interference. The Papazian tests (table 1) indicated that either positive chromosomal interference or negative chromatid interference occurs in some regions; this effect is too weak to be manifest in individual families. Although chromosomal interference was not evident in the three-point tests of any one family, there was some evidence from lumped data that it occurs. Negative chromatid interference is clearly evident in the three-point tetrad data. This effect varies from family to family, and does not appear to be localized to certain regions. The data indicate that chromatid interference is a property conferred by the specific hybrid rather than a fixed property of any given chromosomal region. In this connection it is interesting to note that family 118, which exhibits chromatid interference, was obtained from a intraascal hybrid from family 108, which also shows chromatid interference, suggesting that this family-specific effect may be hereditary.This work has been supported by the Americal Cancer Society.     

Evaluating self-incompatibility in Chrysanthemum

Summary The impact of ovule number on seed set calculations for self-incompatible (SI) species was investigated. Diploid Chrysanthemum was chosen for this study because accurate counts of the potential number of ovules could be made. Individuals in populations of C. carinatum, C. coronarium, C. c. subsp. spatiosum, and C. segetum were crossed in complete diallels. All species exhibited similar results. Therefore, only the diallel data from C. coronarium subsp. spatiosum were presented. The seed set data with and without ovule counts were processed by SIGMAS, a computer program designed to analyze SI data. Incorporation of the actual number of ovules into seed set diallels provided the most realistic representation of values for self-incompatibility studies. Data derived from equations excluding ovule counts might lead to inaccurate genetic interpretations. Ovule counts were significant between and within genotypes for self (disc and ray florets), but not cross (ray florets only) pollinations. The disc florets in self-pollinations were found to be responsible for increasing the variability in ovule number. The statistics indicate that the disc and ray florets composed two distinct populations. At the diploid level with a single daisy flower type, the disc floret numbers were variable, whereas ray florets were relatively static. This was not the case with polyploid chrysanthemums, where both ovule populations were dynamic and interactive. The conservative nature of percent pseudo-self-compatibility (%PSC) deems it necessary to obtain an accurate measure of female fertility. Values for this could be obtained using a bulk pollination or a tester with unmatched S alleles.Scientific Journal Series paper no. 15,880 of the Minnesota Agricultural Experiment Station.     

The endosperm seed protein Solin: biochemical characterization,induction by ABA and species-specific subunits

Summary Comparison of endosperm storage protein sub units from single seeds of 19 Solanum species was done by isoelectric focusing. Species-specific profiles of the subunits were evident and species relationships within a taxonomic series could be delineated. The identification of both intraspecific and interspecific hybrid seed may be possible from Solin IEF subunit profiles. The glutelin nature of the protein was unusual for a dicotyledon genus. We named this major endosperm protein complex Solin. Solin was found in developing seeds with embryos at the heart stage, 16 to 18 days after pollination. Seeds excised at the globular stage responded to the addition of ABA and synthesized Solin. This is the first report of the induction of seed protein in endosperm cells of Solanum.Scientific journal series article No. 14703 of the Minnesota Experiment Station     

Rapid estimation of potato tuber total protein content with coomassie brilliant blue G-250

Summary A new method for measuring protein with Coo-massie Brilliant Blue G-250 has been adapted for use as a screening method in a potato tuber protein improvement breeding program. The method is simple, fast and inexpensive, and has successfully estimated the total protein content of a broad range of tuber genotypes having dissimilar amino acid profiles and tuber maturities. Correlation between the Coomassie method and a modified micro-Kjeldahl method, the standard method used in the potato breeding program, was 0.93. Free amino acids and other compounds which interfere with other methods for measuring protein do not interfere with the Coomassie Brilliant Blue procedure.This research was supported in part by the Rockefeller Foundation. Scientific Journal Series Article # 10,157 of the Minnesota Agricultural Experiment Station     

Tuber proteins from haploids,selfs, and cultivars of group tuberosum separated by acid gel disc electrophoresis

Summary Tuber extracts of 46 cultivars (American varieties), and 350 haploids (2n=24) and selfs (2n=48) from four parents (2n=48), were analysed by acid gel disc electrophoresis. This system separated proteins into 12–14 bands. Twelve cultivars possessed unique patterns of bands, and the remaining cultivars could be placed in groups on the basis of 8 different banding patterns. Distinctions between varieties within groups was accomplished by either esterase or peroxidase isozyme patterns. The usefulness of basic gel proteins, esterase, and peroxidases for varietal identification is known; the acid gel protein patterns described provide a fourth system.Proteins from haploids and selfs were examined for variation in frequency and presence of bands. Differences among bands of the 4 parents were minor. Most haploids and selfs possessed the same bands as their parents, but there were interesting exceptions. The frequency of certain bands was significantly higher in selfs than in haploids. The results fit what would be expected if the parent tetraploid is simplex for a dominant allele controlling the production of each protein. Other bands are more frequent in haploids than selfs and some bands are present in haploids and not in the parent. Suppressor genes in the tetraploids may account for these latter results.

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Zusammenfassung Knollenextrakte von 46 Klonen amerikanischer Kartoffel-Sorten sowie von 350 Haploiden (2n=24) und Selbstungen (2n=48) von vier Eltern (2n=48) wurden mit Hilfe von Disk-Gel-Elektrophorese in saurem Milieu analysiert. Dieses System trennte die Proteine in 12–14 Zonen auf. Zwölf Klone wiesen einheitliche Proteinmuster auf. Die übrigen Klone konnten auf Grund von acht verschiedenen Proteinmustern in Gruppen eingeteilt werden. Unterscheidungen zwischen Sorten innerhalb dieser Gruppen wurden entweder anhand von Esterase- oder von Peroxydase-Isozym-Mustern vorgenommen.Die Brauchbarkeit von basischen Gel-Proteinen, Esterasen und Peroxydasen für die Kennzeichnung von Sorten ist bekannt; die beschriebenen ProteinMuster nach Gel-Elektrophorese im sauren Medium stellen ein neues, viertes System dar.Proteine von Haploiden und Selbstungen wurden im Hinblick auf Variationen in Häufigkeit und Auftreten von Zonen untersucht. Die Unterschiede innerhalb der Protein-Muster der vier Eltern waren geringfügig. Die meisten Haploiden und Selbstungen wiesen die gleichen Zonen auf wie ihre Eltern; jedoch kamen interessante Ausnahmen vor. Gewisse Zonen traten beträchtlich häufiger in Selbstungen als in Haploiden auf.Diese Ergebnisse sind zu erwarten unter der Annahme, daß der tetraploide Elter simplex für ein dominantes Allel ist, das die Synthese eines jeden Proteins kontrolliert.Andere Zonen zeigten sich häufiger in Haploiden als in Selbstungen. Einige Zonen traten nur in Haploiden, nicht aber im Eiter auf. Suppressor-Gene in den Tetraploiden könnten für diese Ergebnisse verantwortlich sein.

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Paper No. 1232 from the Laboratory of Genetics, University of Wisconsin. Supported in part by a grant from the Rockefeller Foundation.