Nuclear and cytoplasmic contributions from <Emphasis Type="Italic">Erianthus arundinaceus</Emphasis> (Retz.) Jeswiet in a sugarcane hybrid clone confirmed through genomic in situ hybridization and cytoplasmic DNA polymorphism

A hybrid between Erianthus arundinaceus (Retz.) Jeswiet and Saccharum spontaneum L. which are wild related species of sugarcane (Saccharum L., Family Poaceae), was repeatedly crossed as female parent with sugarcane commercial varieties to develop near commercial sugarcane clones. The cytoplasm type of the hybrid derivatives were confirmed to be of E. arundinaceus through the mitochondrial and chloroplast DNA polymorphism of nad 4/3-4 intron segment and psbC–trnS segment, respectively. The E. arundinaceus × S. spontaneum hybrid with somatic chromosome number 2n = 62 was confirmed to have 30 chromosomes from E. arundinaceus through genomic in situ hybridization (GISH). The (E. arundinaceus × S. spontaneum) × sugarcane hybrid (2n = 118) had 24 chromosomes from E. arundinaceus whereas its next generation hybrid with sugarcane (2n = 108) had only 12 Erianthus chromosomes. The commercial sugarcane hybrid Co 15015, which is the third generation hybrid with 2n = 106 was confirmed to have two E. arundinaceus chromosomes through GISH. It is the first report of sugarcane with both alien cytoplasm and chromosome contributions from E. arundinaceus.     

C-banded karyotype of <Emphasis Type="Italic">Thinopyrum bessarabicum</Emphasis> and identification of its chromosomes in wheat background

C-banded pattern in two accessions of Thinopyrum bessarabicum (Save ex Rayss) A. Löve (2n = 2x = 14, E^bE^b) and their idiogram was established. C-banding analysis was further used to identify the chromosomes of Tritipyrum amphiploid (2n = 6x = 42, AABBE^bE^b) and a BC₁F₂ genotype from wheat and Tritipyrum. Two 18S-26S rDNA loci were detected on Th. bessarabicum chromosomes by in situ hybridization using an 18S-26S rDNA probe. E^b chromosomes in Tritipyrum generally were identified by their distinctive C-banding patterns which reflected heterochromatin regions. C-banding procedure resulted in sharp and distinct bands in one or both ends of E^b chromosomes without interval bands. Observed C-bands in E^b genome mainly reflected the telomeric and subtelomeric sequences which also showed more strong signals in genomic in situ hybridization. Results showed the importance of the C-banding technique as a screening tool in identification of addition and substitution lines in the progenies of wheat and Tritipyrum crosses during segregating generations.     

Phenotypic diversity in Cajanus species and identification of promising sources for agronomic traits and seed protein content

A total of 198 accessions representing 18 species of the genus Cajanus, assembled at the ICRISAT genebank, was characterized for 27 morpho-agronomic traits at ICRISAT farm, Patancheru, India. Newman–Keuls test of significance for mean values indicated significant differences among the species for one or more traits under study. Mean diversity for all traits was maximum in C. scarabaeoides (H′ = 0.590 ± 0.010). First three principal components (PCs) captured 84.3 % of total variation among all species. Cluster analysis resulted in three clusters. C. albicans and C. mollis formed Cluster 1; C. cajanifolius, C. crassus and C. platycarpus formed Cluster 2 and C. acutifolius, C. scarabaeoides, C. lineatus and C. sericeus formed Cluster 3. C. platycarpus for extra early flowering (34–40 days); C. scarabaeoides for early flowering (51–118 days); C. albicans for broad pods; C. mollis, C. albicans, C. cinereus for more seeds per pod (>6) and C. crassus, C. cajanifolius, C. mollis, C. platycarpus and C. albicans for high seed protein (>30 %) were found as promising sources. Long duration perennial species such as C. crassus, C. mollis and C. albicans are good sources for forage. Five accessions (ICP 15661, ICP 15664, ICP 15666, ICP 15668 and ICP 15671) of C. platycarpus, two accessions (ICP 15653 and ICP 15658) of C. mollis and one accession each of C. acutifolius (ICP 15611), C. albicans (ICP 15620), C. cajanifolius (ICP 15632), C. crassus (ICP 15768), C. lineatus (ICP 15646), C. scarabaeoides (ICP 15922) and C. sericeus (ICP 15760), found as promising for multiple trait combinations are useful in pigeonpea improvement programs.     

Molecular characterization of <Emphasis Type="Italic">Triticum militinae</Emphasis> derived introgression lines carrying leaf rust resistance

Triticum militinae Zhuk. et Migusch. belongs to timopheevii [Triticum timopheevii (Zhuk.) Zhuk.] group of wheats with 2n = 4x = 28 chromosomes and genome formula A^tA^tGG. Triticum militinae Zhuk. et Migusch. is known to carry resistance to fungal diseases including rusts and powdery mildew. Genes from timopheevii wheat can be incorporated into cultivated wheat by either direct hybridization or through development of amphiploids. Three T. militinae derived introgression lines (ILs) Triticum Militinae Derivative (TMD) 6-4, TMD7-5 and TMD11-5 were selected for the current study based on cytological stability. All three ILs showed resistance against wide spectrum of Indian pathotypes of leaf rust. More than 1200 SSR markers were used for genotyping of ILs and parental lines. The ILs showed variable and multiple introgressions in different chromosomes of A, B and D genome of wheat. The introgression points were distributed mostly in the distal regions though significant introgressions were also observed in proximal regions of some chromosomes. The extent of introgression in ILs TMD6-4, TMD7-5 and TMD11-5 was 2.8, 8.3 and 8.6% respectively. The set of ‘informative markers’ in the Molecularly Tagged Chromosome Regions (MTCR) of T. militinae origin can also be used in future for tagging of genes associated with traits of economic importance apart from leaf rust resistance. The transferability of Triticum aestivum L. SSR markers to T. militinae was 96.4% for A genome, 95.8% for B genome and 84.3% for D genome. Transferability of wheat SSR markers to T. militinae can be used in preparing genetic maps in timopheevii group of wheats.     

Development and identification of a wheat-<Emphasis Type="Italic">Psathyrostachys huashanica</Emphasis> addition line carrying HMW-GS,LMW-GS and gliadin genes

Psathyrostachys huashanica Keng, in the family Poaceae, subtribe Triticeae is an endangered and endemic species of China. It is characterized as Shaanxi, drought tolerant and fungus and disease resistant. In this paper, a wheat (Triticum aestivum L.)—P. huashanica disomic addition line “H9021-28-5” was developed using cytogenetics methods including SDS–PAGE, A-PAGE, and GISH. These investigations revealed that the chromosome number and configuration of “H9021-28-5” were 2n = 44 = 22 II. The mitotic and meiotic GISH analysis indicated that “H9021-28-5” contained 42 wheat chromosomes and a pair of P. huashanica chromosomes. The SDS–PAGE and A-PAGE analysis showed that “H9021-28-5” carried the HMW-GS, LMW-GS and gliadin genes of P. huashanica. The results suggest that these storage protein genes of P. huashanica had been transferred into common wheat. Development of this new germplasm is significant for enriching and improving wheat resources of storage proteins genes, and for continuing to exploit the advantageous genes of P. huashanica.     

Characterization of a new T2DS.2DL-?R translocation triticale ZH-1 with multiple resistances to diseases

In the present study, we report on a new triticale (×Triticosecale Wittm.) ZH-1, derived from the progeny of common wheat (Triticum aestivum L.) cv. MY15?×?Chinese Weining rye (Secale cereale L.). ZH-1, exhibiting shorter plant height and higher tillering ability compared to MY15, is immune to both powdery mildew and stripe rust and has stable fertility. Genomic in situ hybridization (GISH), fluorescence in situ hybridization (FISH) and C-banding revealed that the chromosome composition of triticale ZH-1 was 14 A-genome (1A-7A), 12 B-genome (1B-2B, 4B-7B), 12 R-genome (1R, 3R-7R), chromosomes 6D and T2DS.2DL-?R. Moreover, the PCR results of PLUG and EST-SSR markers also strongly supported the above stated chromosome composition of triticale ZH-1. In addition, the physical mapping of chromosome T2DS.2DL-?R showed a minute chromosomal fragment derived from rye was attached at the distal end of 2DL. The new triticale ZH-1 could be a valuable source for wheat improvement, especially for resistance to disease.     

Investigation of genome polymorphism and seed coat anatomy of species of section Adenolinum from the genus Linum

Twelve species of section Adenolinum from genus Linum have been studied using cytogenetic methods (DAPI/C-banding, Ag-NOR staining, FISH with 5S and 26S rDNA probes), RAPD analysis, and seed surface ultrastructure and seed coat anatomy investigation. Karyotype analysis revealed that these species have a chromosome number of 2n = 18 or 2n = 36. The DAPI/C-banding patterns enabled the identification of all chromosomes and revealed the similarities in chromosome patterns in all of the studied species. It was found that 18-chromosome plants are diploids, whereas 36-chromosome forms are tetraploids. In diploid species, 5S and 26S rRNA genes are located in similar positions on a single pair of chromosomes or on two chromosome pairs in tetraploids. Ag-NOR staining showed NOR activity in both genomes of tetraploids. RAPD analysis and seed coat anatomy investigation revealed some interspecies differences. Species from nearby areas have more similar RAPD characteristics compared with more geographically distant species. The results of this study may serve as an additional argument in favour of a monophyletic origination of the Adenolinum species and its strong isolation from other Linum species.     

Genomic reshuffling in advanced lines of hexaploid tritordeum

Genomic restructuring was detected in newly synthesized tritordeum by molecular and cytogenetic tools. Genomic stability is expected for advanced tritordeum lines (H^chH^chAABB; 2n = 42) with multiple generations of self-fertilization. This study intends to confirm or decline this hypothesis by characterizing three advanced tritordeum lines and their parental species using cytogenetics, inter-simple sequence repeat (ISSR) and retrotransposon-based markers. Mitotic chromosomes of each tritordeum line were hybridized with six synthetic oligonucleotide probes using non-denaturing fluorescence in situ hybridization. Polymorphic hybridization patterns and structural rearrangements involving SSR regions were detected. The same chromosome spreads were re-hybridized with genomic DNA of Hordeum chilense Roem. et Schult. and the 45S ribosomal DNA (rDNA) sequence pTa71. These FISH experiments allowed for parental genome discrimination, identification of nucleolar chromosomes, and detection of structural rearrangements, mostly involving rDNA loci. The chromosomes bearing SSR hybridization signals and/or chromosomes involved in structural rearrangements were identified. ISSR, retrotransposon-microsatellite amplified polymorphism, inter-retrotransposon amplified polymorphism and inter-primer binding site markers evidenced genomic reshuffling in all tritordeum lines relative to their parents. Line HT28 was considered the most genetically stable. This work demonstrated that cytogenetic and molecular monitoring of tritordeum is needed, even after several self-fertilization generations, to guarantee the selection of the most stable lines for improvement and sustainable agriculture.     

Keys for and morphological character variation in some Egyptian cultivars of Cucurbitaceae

The cultivated varieties and landraces of Cucurbitaceae growing in Egypt are presented, 27 taxa, belonging to three genera, six species, and five subspecies. These characters are arranged according to their usefulness for identifications as follow: fruit characters, seed characters and trichome type. Fruit characters are a good taxonomic tool at varietal level when combined with the other vegetative characters. Two keys to 27 cultivated varieties of Cucurbitaceae (Cucumis, Cucurbita and Luffa) were constructed using the DELTA software system. One key is used for identification, and then the other is used as a confirmatory key. Those keys were built using 36 morphological characters include vegetative, floral, fruit and seed characters. There is a significant correlation between seed size and growth parameters. The growth parameters of the studied taxa included leaf length/size, petiole length and corolla length. There is a highly positive, significant correlation between seed volume and leaf size (r = 0.81831, P ≤ 0.001), seed volume and petiole length (r = 0.79112, P ≤ 0.001), seed volume and leaf length (r = 0.83566, P ≤ 0.001), and seed volume and corolla length (r = 0.59108, P ≤ 0.001).     

Microsatellite mapping of the genes for sham ramification and extra glume in spikelets of tetraploid wheat

The loci for expression of prolonged spikelet rachilla named ‘sham ramification’ in three tetraploid wheat accessions, two accessions of Triticum jakubzineri Udacz. et Schachm. (2n = 4× = 28, genome BBAA) ‘PI 585014’ and ‘R-101-03’ and one sample of Triticum turgidum L. (2n = 4× = 28, genome BBAA) ‘PI 67339’, were mapped by genotyping F₂ populations using microsatellite markers. The segregation analysis confirmed that sham ramification was controlled by recessive, epistatic genes, shr1 (sham ramification 1) and shr2 (sham ramification 2). The genotypes of ‘sham ramification’ were shr1shr1Shr2Shr2 for T. jakubzineri and Shr1Shr1shr2shr2 for T. turgidum (PI 67339). Normal rachilla was determined by Shr1Shr1Shr2Shr2. The shr1 gene and the gene for extra glume (exg) were completely linked; and, the shr1/exg gene complex was bracketed by the markers Xbarc319 and Xbarc232 on the long arm of chromosome 5A. In the F₂ of PI 67339/LD222 the gene shr2 was bracketed by Xwmc819 and Xwmc794 on the long arm of chromosome 2A.     

Molecular cytogenetic characterization of the amphiploid between bread wheat and Psathyrostachys huashanica

A new wheat-Psathyrostachys huashanica amphiploid, PHW-SA, was characterized using molecular cytological tools to evaluate the potential utilization of P. huashanica for wheat improvement. PHW-SA pollen mother cells (PMCs) regularly revealed averagely 0.57 univalents, 24.51 ring bivalents, 3.19 rod bivalents and 0.01 trivalents per cell. Complete homologous chromosome pairing was seen in 81% of the PMCs, indicating a degree of cytological stability. P. huashanica C-banding karyotypes of PHW-SA displayed strong heterochromatin terminal bands at either or both ends. 24 P. huashanica chromosome arms showed telomeric bands. Using P. huashanica DNA as a probe and J-11 DNA as blocker, distinctive P. huashanica chromosomes, which were presented entirely greenish-yellow hybridization signals, were observed in a somatic metaphase of PHW-SA. GISH also revealed the chromosomal breakage and translocation occurring in the amphiploid PHW-SA, which may represent a centromeric fusion between P. huashanica and wheat chromosomes. Seeds storage proteins electrophoresis indicated that PHW-SA expressed some of P. huashanica specific gliadin and glutenin bands, and a few gliadin and glutenin bands of the parents disappeared and new bands appeared. The results indicated that the amphiploid PHW-SA could serve as novel germplasm sources for wheat improvement.     

Modeling Soil Organic Carbon with DNDC and RothC Models in Different Wheat-Based Cropping Systems in North-Western India

ABSTRACT

The performance of DNDC (DeNitrification-DeComposition) and RothC (Rothamsted Carbon model) in simulating soil organic carbon (SOC) storage in soils under rice (Oryza sativa L.) – wheat (Triticum aestivum L.), maize (Zea mays L.) – wheat and cotton (Gossypium hirsutum L.) – wheat cropping systems was evaluated on field and regional scale. Field experiments consisted of N, NP, NK, PK, NPK, FYM, N + FYM, NPK + FYM, and control (UF) treatments. DNDC and RothC over-estimated SOC storage by 0.35–1.16 Mg C ha^?1 (6–21%) in surface layer with manure application, compared with inorganic fertilizer treatments by 1.01–1.16 Mg C ha^?1 (14–18%). Although RothC only slightly over-estimated SOC stocks, DNDC provided a better match for measured versus simulated SOC stocks (R ² = 0.783*, DNDC; 0.669*, RothC, p < .05). Model validation on independent datasets from long-term studies on rice–wheat (R ² = 0.935**, DNDC; R ² = 0.920**, RothC, p < .01) and maize–wheat (R ² = 0.895** for DNDC and R ² = 0.967** for RothC, p < .01) systems showed excellent agreement between measured and simulated SOC stocks. On a regional scale, change in SOC storage under Scenario 1 (NPK) was significant up to 8 years of simulation, with no change thereafter. In Scenario 2 (NPK + FYM), DNDC simulated SOC storage after 10 years was 2.0, 0.4, and 1.4 Mg C ha^?1 in three systems, respectively. Amount of C sequestered in silt + clay fraction varied between 0.31 and 0.97 kg C 10 years^?1 (Mg silt + clay)^?1 under Scenario 1, and between 0.78 and 2.67 kg C 10 years^?1 (Mg silt + clay)^?1 under Scenario 2.     

Phenotypic and genetic characterization of Kyrgyz fine-leaved Festuca valesiaca germplasm for use in semi-arid,low-maintenance turf applications

Fine-leaved Festuca valesiaca Schleich. ex Gaudin (2n = 2x–4x) is native to heavily-grazed, cold, semi-arid, Asian rangelands. However, its potential for low-maintenance turf applications in the semi-arid western United States and its relatedness to other agriculturally important Festuca species have not been investigated. Therefore, a project was designed to identify F. valesiaca accessions that possess horticultural potential when grown under semi-arid growing conditions and to characterize their relatedness to other Festuca species. In 2008, 12 F. valesiaca accessions originating from Kyrgyzstan and eight US. Festuca and one Lolium cultivar were transplanted as replicated, spaced plants to a field nursery at Blue Creek, Utah. Relative vigor, height, width, total biomass (aboveground dry matter yield), seed weight, and seed number were evaluated between 2009 and 2011. Plant height, width, and total biomass of the F. valesiaca accessions examined were approximately equal to the commercial control, ‘Cascade’ (F. rubra L. subsp. commutata Gaudin; 6x; chewings fescue). Plant vigor and seed weight of F. valesiaca accessions PI 659923, PI 659932, W6 30575, and W6 30588 under semi-arid conditions (~300 mm annual precipitation) were significantly (P < 0.05) greater than ‘Cascade’. Moreover, principal component analysis based on all traits as loading factors indicated that these 12 F. valesiaca accessions were distinct from a majority of the other Festuca accessions examined. These F. valesiaca accessions produced abundant amounts of small seed, and this seed yield was significantly correlated with total aboveground biomass (dry weight; r ²  = 0.84, P < 0.001), plant height (r ²  = 0.58, P < 0.05), and plant vigor (r ²  = 0.83, P < 0.001). Amplified fragment length polymorphism (AFLP) analysis (1,454 polymorphic bands) was used to characterize F. valesiaca relatedness to other economically important Festuca species. The AFLP-based, neighbor-joining analysis differentiated F. valesiaca accessions from US Festuca cultivars examined, except for ‘Durar’ (F. ovina L.; 6x; sheep fescue), to which they had strong genetic affinities. Given their morphological attributes, F. valesiaca PI 659923, W6 30575, PI 659932, and W6 30588 should be considered for use in low-maintenance, semi-arid turf improvement programs in the western US.     

Evaluation of seed yield and seed yield components in red–yellow (Pisum fulvum) and Ethiopian (Pisum abyssinicum) peas

Red–yellow (Pisum fulvum Sibth. et Sm.) and Ethiopian (Pisum abyssinicum A. Br.) peas have become of increasing interest to breeders in the last decade, as they have been found to be partially or completely tolerant to various biotic stresses, such as to attack by pea weevil, mildew blight or rust. A trial was carried out at the Institute of Field and Vegetable Crops at Rimski ?an?evi from 2005 to 2007, with 13 accessions each of red–yellow and Ethiopian peas sown at 100 viable seeds m^?2, in plots of 0.5 m². Seed yield per plant in red–yellow pea was significantly and positively correlated with seed number per plant (r = 0.881**), pod number per plant (r = 0.839**) and number of fertile nodes (r = 0.820**). The highest positive correlation among the agronomic characteristics in Ethiopian pea was between number of fertile nodes and number of pods (r = 0.937**). Seed yield in Ethiopian pea was highly significantly correlated with number of seeds (r = 0.807**), pods (r = 0.692*), and fertile nodes (r = 0.638*). The results suggest that plant morphology of the progenies between red–yellow or Ethiopian peas and grain-type common pea could not differ significantly from that of individual parents. That means that it could be possible to develop hybrid lines that could keep the desirable morphological traits of grain-type common pea, such as lodging-tolerance and high seed yields, and to make an introgression of a specific resistance from wild pea taxa, especially by back-crosses with the former. However, one must always be aware of unpredicted outcomes as a result of rather different genetic basis of individual seed yield components.     

<Emphasis Type="Italic">Lotus ornithopodioides</Emphasis> L. a potential annual pasture legume species for Mediterranean dryland farming systems

Twenty-three populations of Lotus ornithopodioides L., collected from different regions of the Mediterranean basin, were investigated for their ecological and agronomic traits in Western Australia. Great variability was found between and within populations for flowering time, forage and seed yield. Flowering time ranged between 75 and 120 days, dry matter production from 2.8 to 4.3 t ha^?1 and seed yield from 284 to 684 kg ha^?1. Other important traits such as non-shattering pods and hard seed were taken into account during the selection to assure an easy seed harvesting and legume persistence in the targeted environments. The high level of hard seed recorded in early winter, associated to the low seedling regeneration, indicates that L. ornithopodioides is best suited to ley cropping systems. Elite lines of L. ornithopodioides characterized by early flowering time, high seed yield and non-shattering pods were selected. Two of them, LOR02.1 and LOR03.2, showed dry matter higher than 4.0 t ha^?1 and seed yield around 700 kg ha^?1 resulting the lines with most potential for Mediterranean farming systems. The results encourage the exploitation of L. ornithopodioides germplasm to develop a new annual self-reseeding legume resource for Mediterranean farming systems for both forage production and crop rotation uses.     

Patterns of SSR variation in bread wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.) seeds under ex situ genebank storage and accelerated ageing

Maintaining seed viability and germplasm integrity is a challenging task in conservation of plant genetic resources, as seeds under storage will lose viability and genetic changes will occur. Attempt was made to analyze the patterns of genetic changes in wheat germplasm under ex situ genebank storage and accelerated ageing treatments. A set of 16 naturally aged wheat accessions under ex situ genebank storage since 1994 were sampled. Four recently regenerated wheat accessions were selected, four random seed samples were chosen from each accession, and three of them were exposed to three different accelerated ageing treatments. These 32 seed samples in two germplasm sets displayed a range of germination rates from 4 to 98 %. Thirty-seven microsatellite markers representing 21 wheat chromosomes were applied to screen 12 seeds of each sample and 449 SSR alleles were scored. Large SSR variation was found in each germplasm set. There was 73.1 % of the total SSR variation present among the naturally aged samples and 78.2 % present among the accelerated ageing samples. Several analyses for genetic association consistently revealed no clear genetic separations among samples of high or low germination rates in both germplasm sets. Samples under different accelerated ageing treatments did not show much genetic differentiations from the original sample of each accession. Mantel tests revealed non-significant associations between SSR variability and sample germination rates for both germplasm sets. These findings are useful for understanding seed deterioration under different ageing conditions and suggest that genome-wide SSR variability may not provide sensitive markers for the monitoring of wheat seed viability.     

Halotolerant rhizobacteria: beneficial plant metabolites and growth enhancement of Triticum aestivum L. in salt-amended soils

Salt-tolerant strains of Enterobacter asburiae, Bacillus thuringiensis, Moraxella pluranimalium and Pseudomonas stutzeri were evaluated for their ability to alleviate salt stress of wheat (Triticum aestivum L.) seedlings. 1-Aminocyclopropane-1-carboxylate deaminase activity of P. stutzeri S-80 and B. thuringiensis S-26 was 190 and 183 nmol h^?1, respectively. Maximum levels of auxin were recorded with P. stutzeri S-80 (107 µg ml^?1) and E. asburiae S-24 (143 µg ml^?1) under normal and salt-stressed conditions (0.25M NaCl), respectively, with 500 µg ml^?1 L-tryptophan. Auxin response mediated by rhizobacteria was also demonstrated by microscopically assaying the transgenic auxin-responsive reporter DR5::GUS expression tomato (Solanum lycopersicum L. cv. MicroTom). In pot trials, seedlings fresh and dry biomass witnessed highly significant improvements of 1- and 2.2-folds, respectively, with M. pluranimalium S-29 (at 100 mM NaCl) and E. asburiae S-24 (150 mM NaCl), over control. At final harvest, maximum increase in number of tillers (up to 94%) and seed weight (up to 40%) was recorded with E. asburiae S-24 and M. pluranimalium S-29 at 200 mM salt stress. In conclusion, newly isolated strains of M. pluranimalium S-29, E. asburiae S-24 and P. stutzeri S-80 enhanced the growth of T. aestivum by mitigating the salt stress of plants.     

小麦-鹅观草易位系T7A/1Rk#1的选育与鉴定

将小麦-鹅观草del1Rk#1L二体添加系的花粉用10 Gy 60Co γ射线照射处理,给小麦中国春授粉,获得杂种。综合利用C-分带、GISH、顺次C带/45SrDNA-FISH和顺次GISH/45SrDNA-FISH等分子细胞遗传学技术在M2代筛选和鉴定出1个涉及小麦7A和鹅观草1Rk#1染色体的相互易位染色体系,并获得1Rk#1染色体的1个45SrDNA位标,该位标和其对应的红色GISH-带纹能够特异地识别1Rk#1染色体短臂。对M2代群体染色体组成分析和测交分析表明,两条易位染色体在后代中以共分离方式成对出现,且易位通过雌配子的传递率高于雄配子。综合2004、2005和2006 3年的赤霉病抗性鉴定结果表明：该易位系对赤霉病表现部分抗病,但抗性表现在不同年份、不同地点有差异。试验还证明花粉辐射是诱导小麦-外缘物种染色体易位的有效方法。     

Origin and cytology of a novel cytotype of Allium tuberosum Rottl. ex Spreng. (2n = 48)

Naturally occurring/spontaneously produced polyploids with six/more genomes are rarely found in Alliums. A hexaploid form of Allium tuberosum with 2n = 48 chromosomes has been isolated for the first time amongst the open-pollinated seedlings of a hypotetraploid plant (2n = 4x = 31); latter being the seed-derived product of a normal tetraploid stock (2n = 4x = 32) growing in Jammu University Botanical Garden. Except for the guard cells and pollen grains that are of increased size, this form compared to its progenitor is dwarf, has smaller leaves and bears inflorescences with few flowers. This plant is also different from its progenitor in having nearly one-fourth (27.8 %) of its pollen mother cells (PMCs) with varying chromosome number viz. 27–64, with the remaining cells having somatic or double the somatic number of chromosomes. To assess the nature of hexaploid form, its chromosomes were studied for morphological details, putative grouping and pairing properties during reduction division. Morphological similarity in the chromosomes of the present cytotype and its progenitor, arrangement of 48 chromosomes in eight groups of six chromosomes each and presence of 21.88 % euploid cells with eight hexavalents pointed towards the autopolyploid nature of the present strain. Regarding the origin of this strain, observation made on the meiosis in the two sex mother cells of the progenitor provides some clues. In the later plant, presence of most of embryo-sac mother cells with 62 chromosomes that showed 31:31 segregations and existence of majority of the PMCs with 31 chromosomes exhibiting erratic segregations indicate that the hexaploid strain has probably originated as a result of the fusion of reduced male (n = 17) and unreduced female gamete (2n = 31).     

Allelic diversity of high molecular weight glutenin subunits (HMW-GS) in Iranian Aegilops tauschii Coss. accessions by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE)

Variation of high molecular weight glutenin subunits (HMW-GS) in 28 Iranian Aegilops tauschii (2n = 2x = 14, DD) accessions studied by sodium dodecyl sulphate electrophoresis method (SDS-PAGE). The results showed high variation of HMW-GS in the accessions. The range of frequency in 14 HMW-GS combinations was 3.57–25 % in the accessions. AMOVA showed the molecular variance between the geographic areas was lower than within the geographic areas. According to Nei’s genetic diversity, the highest diversity levels were in Semnan, Golestan and Azarbayjan, on the other hand the lowest levels of diversity were found in Khorasan, Gilan and Mazandaran accessions. Hence, the Caspian Sea South East accessions also Azerbayjan in Iran have more diversity. AMOVA did not show variance between strangulata and tauschii but there was more genetic diversity in ssp. tauschii subspecies in comparison of ssp. strangulata according to Nei’s gene diversity and Shannon information index. It showed Iranian Ae. tauschii have a good potential for bread making quality improvement in bread wheat.