Showing 4 results for Hybridization
J. Panahandeh, S. Massiha,
Volume 8, Issue 2 (7-2004)
Abstract
The commercial potato is an autotetraploid species. Certain allotetraploid species such as S. acaule despite theire identical ploidy level are not crossable with commercial potato due to their different endosperm balance numbers. The aim of this experiment was to investigate the possibility of germplasm transferring from allotetraploid species to cultivated potato by the use of diploid species and 2n gametes. For this purpose, one clone of S. phureja was crossed with S.acaule. The resulting F1 seeds were planted the next year. For evaluation of male fertility and unreduced gametes, the pollen samples of F1 hybrids stained with acetocarmin glycerol were assessed. For chromosome counting the tips of stolons were fixed and after staining with aceto – iron- hematoxilin were squashed. For future crossing some hybrids were grafted on tomato stocks. Cytologycal observation revealed that hybrids were triplod. Male fertility of hybrids as expected for odd ploidy was low, but approximately all of them had a few large stainable pollen (putative 2n). crossing of the hybrids as male parent with S. tuberosum was not successful, but reciprocal cross was successful and 72 seeds were obtained from 380 pollination . considering EBN, it is exected that the resulting seeds originate from fertilization of unreduced gametes of triploid and n gamates of S. tuberosum to be pentaploid or near pentaploid. The applications of these hybrid in potato breeding via ploidy manipulation have been discussed.
T. Mahmoodi-Ghehsareh, B. E. Sayed-Tabatabaei, C. Ghobadi, A. Mirlohi,
Volume 8, Issue 3 (10-2004)
Abstract
The significance of haploid plants as genetic and plant breeding tools has been recognized for a long time. Haploid production techniques including anther culture, isolated microspore culture and intergeneric hybridization between wheat × Hordeum bulbosum and wheat × maize have been used to produce homozygous lines which accelerate breeding programs. In this study, wheat × maize hybridization and anther culture techniques were used for haploid production in six wheat genotypes. The results showed that 70.7% of regenerated plants through anther culture were albino plants and only 29.2 % were green, while the plants produced through wheat × maize method were all green. Ploidy variation was not observed in plants regenerated through wheat × maize hybridization. It was concluded that wheat × maize crosses would be an appropriate and practical method for haploid production in different wheat genotypes, which in comparison with the anther culture method has a higher efficiency.
J. Erfani Moghaddam, A. Ebadi, M. Fatahi Moghaddam,
Volume 12, Issue 45 (10-2008)
Abstract
Seedlessness is the most important characteristic of fruit quality for raisin and table grapes. Grape breeding at University of Tehran, Karaj branch, Iran started in 1999 with crossing some selected seedless and seeded cultivars at the end of evaluation of 90 cultivars in grapevine collection of College of Agriculture in Karaj. Out of 1400 progeny obtained from 26 different crosses, 381 of them which produced fruits were evaluated during growing seasons of 2006 & 2007. Progenies were divided into four groups of completely seedless, semi-seedless, semi-seeded and completely seeded, according to seed trace or seed weight. Results classified progeny to 11% completely seedless, 13.6% semi-seedless, 24% semi seeded and 51.2% completely seeded. Percentages of seedless progeny for four male parents of Askary, Yaghooti, Bidane Sefid and Bidane Ghermez were 15.4%, 10.8%, 9.3% and 10.6%, respectively. Meanwhile, percentages of seedless progeny for female parents of Muscut of Hamburg, Ghezel Uzum, Dizmary, Rajabi Sefied, Ali Baba, Alhaghi Ghermez and Tabariz were 5.4%, 5%, 17.5%, 13.2 %, 1.4%, zero and 36%, respectively. Results also showed that among male parents, Yaghooti and Bidane Ghermez cultivars and among female parents, Tabarze cultivar had better backgrounds to transmit stenospermocarpic seedlessness characteristics.
S Falahati Por, H Shahsavand Hasani, A Baghizadeh, Gh Karimzadeh,
Volume 13, Issue 48 (7-2009)
Abstract
The genomic in situ hybridization (GISH) has been used to identify euploidy and aneuploidy in segregation generations of various plants. In this study, the GISH with minor modifications including, slide preparation of putative secondary Tritipyrum (F2) root meristemic cells, labeled genomic DNA of Thinopyrum bessarabicum by fluorescein 12-dUTP nucleotide as probe, genomic DNA of Thinopyrum bessarabicum for in situ hybridization on root meristemic cells of F2 (2n=6x=42, AABBDEb) and unlabeled Chinese Spring cultivar in pre hybridization, was carried out for the first time in Iran. The results not only indicated the various Eb chromosomes in putative 6x secondary Tritipyrum plants, but also showed different numbers of A, B and D chromosomes. The range of aneuoploidy in F2 genotypes was from %30 to %66.7, which could be due to various numbers of Eb and D chromosomes in each genotype. The selfing or back crossing of F2 plants with bread wheat varieties could lead to chromosomal stability and aneoploidy reduction in secondary Tritipyrum genotypes.
