Formation of first division restitution (FDR) 2n-megaspores through pseudohomotypic division in ds-1 (desynapsis) mutants of diploid potato: routine production of tetraploid progeny from 2xFDR × 2xFDR crosses

1991 ◽  
Vol 82 (5) ◽  
pp. 645-656 ◽  
Author(s):  
E. Jongedijk ◽  
M. S. Ramanna ◽  
Z. Sawor ◽  
J. G. Th. Hermsen
Genome ◽  
1992 ◽  
Vol 35 (5) ◽  
pp. 741-745 ◽  
Author(s):  
Joanna E. Werner ◽  
David S. Douches ◽  
Rosanna Freyre

The ratio of the first division restitution (FDR) to second division restitution (SDR) 2n eggs was estimated in 4182t, a haploid (2n = 2x = 24) of Solanum tuberosum L. that produces 2n eggs by the two modes. The segregation of three genes previously mapped relative to their centromeres, Pgm-2 (2.0 cM), Mdh-1 (33.5 cM), and 6-Pgdh-3 (30.1 cM) was analyzed in the tetraploid offspring of a 2x × 4x cross. Based on the segregation of the Pgm-2 locus, 39.7% of the progeny originated from FDR 2n eggs and 60.3% from SDR. Segregation patterns of the two distal loci within the FDR-derived 4x subpopulation indicated that the gene–centromere recombination rate during megasporogenesis was significantly reduced for Mdh-1 when compared with a previous estimate during microsporogenesis. In the SDR-derived 4x subpopulation, the gene–centromere recombination rates for Mdh-1 and 6-Pgdh-3 were not significantly different from previous estimates. Tetraploid progeny generated from one 2x × 4x cross where the 2x parent produces 2n gametes by two modes can be used to make an unbiased comparison of the potential breeding value of FDR and SDR gametes.Key words: potato, megasporogenesis, first division restitution, second division restitution, isozyme.


In the years since the publication of Atherton and Sheppard's volume, the technique of Fmoc solid-phase peptide synthesis has matured considerably and is now the standard approach for the routine production of peptides. The basic problems outstanding at the time of publication of this earlier work have now been, for the most part, solved. As a result, innovators in the field have focussed their efforts to develop methodologies and chemistry for the synthesis of more complex structures. The focus of this new volume is much broader, and covers not only the essential procedures for the production of linear peptides but also more advanced techniques for preparing cyclic, side-chain modified, phospho- and glycopeptides. Many other methods also deserving attention have been included: convergent peptide synthesis; peptide-protein conjugation; chemoselective ligation; and chemoselective purification. The difficult preparation of cysteine and methionine-containing peptides is also covered, as well as methods for overcoming aggregation during peptide chain assembly and a survey of available automated instrumentation.


Genetics ◽  
2002 ◽  
Vol 162 (3) ◽  
pp. 1423-1434
Author(s):  
Cristina M Menéndez ◽  
Enrique Ritter ◽  
Ralf Schäfer-Pregl ◽  
Birgit Walkemeier ◽  
Alexandra Kalde ◽  
...  

Abstract A candidate gene approach has been used as a first step to identify the molecular basis of quantitative trait variation in potato. Sugar content of tubers upon cold storage was the model trait chosen because the metabolic pathways involved in starch and sugar metabolism are well known and many of the genes have been cloned. Tubers of two F1 populations of diploid potato grown in six environments were evaluated for sugar content after cold storage. The populations were genotyped with RFLP, AFLP, and candidate gene markers. QTL analysis revealed that QTL for glucose, fructose, and sucrose content were located on all potato chromosomes. Most QTL for glucose content mapped to the same positions as QTL for fructose content. QTL explaining >10% of the variability for reducing sugars were located on linkage groups I, III, VII, VIII, IX, and XI. QTL consistent across populations and/or environments were identified. QTL were linked to genes encoding invertase, sucrose synthase 3, sucrose phosphate synthase, ADP-glucose pyrophosphorylase, sucrose transporter 1, and a putative sucrose sensor. The results suggest that allelic variants of enzymes operating in carbohydrate metabolic pathways contribute to the genetic variation in cold sweetening.


1982 ◽  
Vol 9 (3) ◽  
pp. 218
Author(s):  
K.H. Assmus ◽  
W. Maier ◽  
R. Schutz ◽  
F. Schulz ◽  
H. Schweickert

2020 ◽  
Vol 44 (4) ◽  
pp. 399-407
Author(s):  
Sarbesh Das DANGOL ◽  
İlknur YEL ◽  
Mehmet Emin ÇALIŞKAN ◽  
Allah BAKHSH

2008 ◽  
Vol 51 (1) ◽  
pp. 83-86 ◽  
Author(s):  
Vanessa Gómez ◽  
Juan Domingo Gispert ◽  
Víctor Amador ◽  
Jordi Llop

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