Nuclear genome size and chromosome analysis in <Emphasis Type=\"Italic\">Chenopodium quinoa</Emphasis> and <Emphasis Type=\"Italic\">C. berlandieri</Emphasis> subsp. <Emphasis Type=\"Italic\">nuttalliae</Emphasis>

Cytogenetic characterization by karyotyping and determination of DNA content by flow cytometry of seven cultivated varieties of Chenopodium was performed. Chenopodium quinoa cultivar Barandales and C. berlandieri subsp. nuttalliae cultigens Huauzontle, Quelite and Chia roja showed 2n = 4x = 36, x = 9. Statistically insignificant genome size differences for studied varieties ranged from 2.96 pg/2C (1 Cx = 724 Mbp) in C. quinoa to 3.04 pg/2C (1 Cx = 743 Mbp) in Huauzontle. Karyotype analyses revealed the presence of nine groups of four metacentric chromosomes, including two pairs of chromosomes with satellites. The first pair of satellites was located on the largest pair of chromosomes and the second on a different pair of chromosomes in all accessions analyzed. Variation among varieties was evident in chromosome size, genome length (GL) and the position of satellites. Chia roja exhibited greatest GL (58.82 μm) and biggest chromosomes (2.04 μm). Huauzontle showed the smallest GL (45.02 μm) and shortest chromosomes (1.60 μm). Comparison of GL in studied taxa was statistically significant and allowed to define three groups according to the use given to these plants. These data indicate that they are small, very stable genomes in terms of DNA content, and they support the allotetraploid origin(s) of C. berlandieri subsp. nuttalliae and C. quinoa.     

Winter curing of <Emphasis Type=\"Italic\">Prunus dulcis</Emphasis> cv ‘Butte,’ <Emphasis Type=\"Italic\">P. webbii</Emphasis> and their interspecific hybrid in response to <Emphasis Type=\"Italic\">Xylella fastidiosa</Emphasis> infections

In traditional quantitative genetics, additive effects of genes acting in a population of biparental homozygous lines are estimated on the basis of the phenotypic observations only, usually by taking a difference between mean values for extreme lines. Current molecular methods allow to estimate the additive effects by additionally taking into account the marker data. In this paper we compare these two methods of estimation of additive gene action effects analytically, by simulations and by analysis of real data sets for doubled haploid lines and recombinant inbred lines. The analytic comparison shows under which conditions an agreement of the two methods can be achieved. In most of the considered experimental data and in simulations we observe that the additive effect calculated on the basis of the marker observations is smaller than the total additive effect obtained from phenotypic observations only. This result is discussed, and a weighted regression approach is proposed as a method which can close the gap between the purely phenotypic and genotypic approaches.     

Genetic parameters for growth traits and stem-straightness in <Emphasis Type=\"Italic\">Eucalyptus urophylla</Emphasis> × <Emphasis Type=\"Italic\">E. camaldulensis</Emphasis> hybrids from a reciprocal mating design

An inter-specific hybrid breeding program involving Eucalyptus urophylla (U) and Eucalyptus camaldulensis (C) was implemented in order to provide genotypes better adapted to southern China with improved growth rate, stem-straightness and wind-resistance. A trial involving 36 reciprocal crosses from six parents each of C and U that had been preselected for superior growth and stem-straightness was established at a site in Luokeng in Guangdong province. Ten, pure-species families using the hybrid parents as open-pollinated female parents were included as controls. Survival and growth traits at ages 2 and 8.3 years and stem-straightness at age 2 years were assessed. Inter-specific hybrids generally performed better than the pure species in terms of survival, growth traits and stem-straightness. Female U by male C crosses generally outperformed those involving male U and female C. Further indication of the significant reciprocal effect was supported by negative and low correlations between paired groups of full-sibs that differed only in the direction of the cross. Components of female additive genetic variance and narrow-sense heritability calculated from this estimate ((sigma_{rm Af}^{2}) and (h_{rm f}^{2})), respectively) were generally higher than those of the male (left( {sigma_{rm Am,}^{2} h_{rm m}^{2} } right)), providing evidence for maternal effects. The narrow-sense heritability (h²) estimates based on general hybridizing ability for growth traits and stem-straightness were generally low at both ages, and of low precision at 8.3 years. The ratio of hybrid additive-to-dominance variance (left( {{{sigma_{rm A}^{2} } mathord{left/ {vphantom {{sigma_{rm A}^{2} } {sigma_{rm D}^{2} }}} right. kern-0pt} {sigma_{rm D}^{2} }}} right)) was of little practical consequence at age 2 years and had further decreased by age 8.3 years. Trait-trait genetic correlations amongst hybrids were generally positive and moderate to high. Hybrid vigour, gauged by comparison with the performance of the pure species progeny was significant, though correlations between pure species and hybrid progeny-based estimates of parental performance were weak, indicating that making parental selections in pure species trials may not be a successful strategy.     

Fine mapping of the <Emphasis Type=\"Italic\">fg</Emphasis> gene using the interspecific cross of <Emphasis Type=\"Italic\">Gossypium hirsutum</Emphasis> × <Emphasis Type=\"Italic\">Gossypium barbadense</Emphasis>

Frego (fg) bract is an important agronomic trait in tetraploid cotton, which has been widely introduced into several cotton varities or lines in the past several years. In order to help us further understand the underlying molecular mechanism of frego bract development, a map-base cloning strategy was used to localize the fg locus. An F₂ population which comprised of 290 fg individuals derived from a cross of the multiple-marker line T582 (G. hirsutum, carrying the fg gene) with Hai7124 (G. barbadense) was constructed. Genetic linkage analysis was carried out to map of the fg locus with SSR and EST-SSR markers in tetraploid cotton. Genetic linkage analysis showed that the fg locus was flanked by the marker NAU3016 and NAU3172 on the long arm of chromosome 3, with the genetic distance of 0.3 cM and 4.7 cM, respectively. The information of fg locus provided the basic information for the final isolation of this important gene in tetraploid cotton, these marker information could be used in marker-assisted selection in cotton.     

Reciprocal differences in DNA sequence and methylation status of the pollen DNA between F<Subscript>1</Subscript> hybrids of <Emphasis Type=\"Italic\">Solanum tuberosum</Emphasis> × <Emphasis Type=\"Italic\">S. demissum</Emphasis>

Reciprocal differences, mostly caused by cytoplasmic effects, are frequently observed in interspecific hybrids. Previously, we found that crosses onto Solanum demissum were much successful with the pollen of interspecific hybrids between S. tuberosum as female and S. demissum as male (TD hybrids) than the reciprocal ones (DT hybrids). To elucidate this reciprocally different crossability, we analyzed the pollen DNA of TD and DT using methylation-sensitive amplified polymorphism (MSAP) analysis. Using 126 primer combinations, MSAP analysis revealed 57 different bands between bulked pollen DNA samples of TD and DT. Individual examination of 16 TD and 9 DT plants disclosed eight bands uniformly different between TD and DT. Their sequencing results revealed two pairs of bands to be identical to each other, resulting in six distinct sequences. As expected, one band shared high homology with chloroplast DNA, and another one with mitochondrial DNA. However, one band that was apparently different at DNA sequence level and maternally transmitted from S. demissum, showed no homology with any known sequence. The remaining three bands were of DNA methylation level differences with no or uncertain homology to known sequences. To our knowledge, this is the first report detecting reciprocal differences in DNA sequence or DNA methylation other than those in cytoplasmic DNA.     

Frequent occurrence of unreduced gametes in <Emphasis Type="Italic">Triticum turgidum</Emphasis>–<Emphasis Type="Italic">Aegilops tauschii</Emphasis> hybrids

Spontaneous chromosome doubling via union of unreduced (2n) gametes has been thought to be the way that common wheat (Triticum aestivum L.) was originated from the hybridization of T. turgidum L. with Ae. tauschii Cosson. Previous works have observed unreduced gametes in F₁ hybrids of Ae. tauschii with six of the eight T. turgidum subspecies. It is not clear, however, whether the formation of these unreduced gametes is a norm in the F₁ hybrids. In the present study, we tried to answer this question by assessing the occurrence frequency of unreduced gametes in 115 T. turgidum–Ae. tauschii hybrid combinations, involving 76 genotypes of seven T. turgdium subspecies and 24 Ae. tauschii accessions. Our data show that these hybrid combinations differed significantly (P ≤ 0.01, F = 11.40) in selfed seedset, an indicator for production of unreduced gametes. This study clearly showed that meiotic restitution genes are widely distributed within T. turgidum. However, significant differences were found between as well as within T. turgidum subspecies and in the interaction of the T. turgidum genotypes with those of Ae. taushii. The possible application of the meiotic restitution genes from T. turgidum in production of double haploids is also discussed.     

Selection of U and M genome-specific wheat SSR markers using wheat–<Emphasis Type=\"Italic\">Aegilops biuncialis</Emphasis> and wheat–<Emphasis Type=\"Italic\">Ae. geniculata</Emphasis> addition lines

We selected wheat SSR markers specific to the U and M genomes of Aegilops species. A total of 108 wheat SSR markers were successfully tested on Ae. biuncialis (2n = 4x = 28, U^bU^bM^bM^b), on five wheat–Ae. biuncialis addition lines (2M^b, 3M^b, 7M^b, 3U^b and 5U^b) and on a wheat–Ae. geniculata (1U^g, 2U^g, 3U^g, 4U^g, 5U^g, 7U^g, 1M^g, 2M^g, 4M^g, 5M^g, 6M^g and 7M^g) addition series. Among the markers, 86 (79.6%) were amplified in the Ae. biuncialis genome. Compared with wheat, polymorphic bands of various lengths were detected on Ae. biuncialis for 35 (32.4%) of the wheat microsatellite markers. Three of these (8.6%) exhibited specific PCR products on wheat–Ae. biuncialis or wheat–Ae. geniculata addition lines. The primers GWM44 and GDM61 gave specific PCR products on the 2M^b and 3M^b wheat–Ae. biuncialis addition lines, but not on the 2M^g addition line of Ae. geniculata. A specific band was observed on the 7U^g wheat–Ae. geniculata addition line using the BARC184 primer. These three markers specific to the U and M genomes are helpful for the identification of 2M^b, 3M^b and 7U^g chromosome introgressions into wheat.     

Breeding of high yielding and dwarf oil palm planting materials using Deli <Emphasis Type=\"Italic\">dura</Emphasis> × Nigerian <Emphasis Type=\"Italic\">pisifera</Emphasis> population

In practice, progeny and individual palm selection are believed to be the most suitable breeding approach for improvement of quantitative traits in oil palm because their phenotypic expressions are strongly influenced by abiotic factors. Therefore progeny selection approach was applied in this study for the selection of high fresh fruit bunch (FFB) and dwarf oil palm planting materials. Cross between Deli dura and Nigerian pisifera resulted into 34 D × P full sib progenies with 1036 seedlings. For six consecutive years, data were collected on yield and yield component traits, while vegetative traits were recorded once. Bi-parental analysis was carried out using analysis of variance, followed by progenies mean comparison, variance components, heritabilities and cluster analysis. Highly significant (P ≤ 0.01) progeny effect was recorded in this study and this had a pronounced effect on the expression of all the quantitative traits. Progenies performance of FFB varied significantly and it ranged from 166.49 to 220.06 kg/palm/year (kg/p/yr) with trial mean of 192.93 kg/p/yr. Palm height after 8 years of field planting ranged from 1.67 to 2.78 m (control cross) with trial mean of 2.12 m. Broad sense heritability (({text{h}}_{text{B}}^{2})) was found to be very low (<17.60%) for all the yield traits, however this parameter was high for vegetative traits with palm height having ({text{h}}_{text{B}}^{2}) of 90%. Cluster analysis based on all the quantitative traits grouped all the 34 DP progenies into nine distinct clusters. From this study, five progenies (DP3, DP4, DP5, DP8 and DP24) were identified to be high yielding and dwarf palms compare to trial mean. At density of 140 palm/ha, they will produce FFB of 28.63–30.81 t/ha and average of 29.69 t/ha which is about 27.15% higher in FFB when compared to the current planting material with FFB of 23.35 t/ha. In addition, the selected progenies possessed average annual palm increment of 29.82 cm/yr with range of 26 and 32.5 cm/yr which was 57.33% shorter than the current planting material with palm height increment of 45–75 cm/yr.     

Mapping and use of seed protein loci for marker-assisted selection of growth habit and photoperiod response in <Emphasis Type=\"Italic\">Nuña</Emphasis> bean (<Emphasis Type=\"Italic\">Phaseolus vulgaris</Emphasis> L.)

The individual segregations of 14 seed protein loci named, SpA to SpM and Pha (phaseolin), were analyzed in a RIL population developed from the cross Xana × Cornell 49242. These seed protein loci were included in a genetic map previously developed in the same population. Protein loci, SpA, SpB, SpE, SpI, SpJ, and Pha, are organized in two different clusters, both located in linkage group (LG) 7; SpF, SpG, SpK, SpL, and SpM, form a single cluster in LG 4; SpC, is located in LG 3; and SpD, in LG 1. A close linkage was identified between the SpD seed protein locus, and the fin gene, controlling determinate growth habit. The usefulness of the SpD locus as a marker for the indirect selection of determinate growth habit and photoperiod insensitivity was checked in a F₂ population derived from the cross G12587 (an indeterminate and photoperiod sensitive nuña bean) × Sanilac (determinate and photoperiod insensitive) and in a set of Mesoamerican and Andean genotypes. Results indicate that SpD protein locus was useful to detect individuals having determinate growth habit and photoperiod insensitivity in the cross G12587 × Salinac although some recombinants were found. However, the linkage between the SpD locus and the genes controlling growth habit and photoperiod sensitivity should be checked before using the SpD locus for the indirect selection of these traits in different backgrounds.     

Alloplasmic effects of <Emphasis Type="Italic">Brassica napus</Emphasis> and <Emphasis Type="Italic">B. juncea</Emphasis> on seed characteristics of <Emphasis Type="Italic">B. carinata</Emphasis>

Effects of Brassica napus (N) and B. juncea (J) cytoplasm on seed characteristics of B. carinata (C) were examined. Alloplasmic lines of B. carinata were produced from N × C and J × C hybrids by recurrent backcrossing to the BC₈ generation. Fourteen sets of reciprocal crosses were used. Compared with their euplasmic sibs, alloplasmic B. carinata line seeds with B. napus cytoplasm showed reduced dormancy, higher seed weight, lower germination rate at high temperatures, higher germination rate at low temperatures, and had lower erucic acid and higher linoleic acid contents. Alloplasmic B. carinata line seeds with B. juncea cytoplasm had higher seed weight but lower germination rate than their corresponding euplasmic sibs. These results showed a cytoplasmic effect on seed development, and an influence on seed weight, dormancy, and fatty acid composition. B. carinata was more deleteriously affected by cytoplasm from B. napus than by cytoplasm of B. juncea.     

Mapping a gene conferring resistance to <Emphasis Type=\"Italic\">Wheat yellow mosaic virus</Emphasis> in European winter wheat cultivar ‘Ibis’ (<Emphasis Type=\"Italic\">Triticum aestivum</Emphasis> L.)

Wheat yellow mosaic, caused by Wheat yellow mosaic virus (WYMV), is one of the most devastating soil-borne diseases of winter wheat (Triticum aestivum L.) in Japan. Yellow-striped leaves and stunted spring growth, symptomatic of WYMV infection, result in severe yield loss. A new putative WYMV resistance gene in the European wheat cultivar ‘Ibis’ was mapped in the cluster of microsatellite markers including Xcfd16, Xwmc41, Xcfd168 and Xwmc181 on the long arm of chromosome 2D at the distances of 2.0 cM, 4.0 cM, 7.1 cM and 12.4 cM, respectively. WYMV-resistant cultivars contained a common haplotype of the four markers, whereas moderately susceptible and susceptible cultivars did not. These results should be useful in marker-assisted selection for WYMV resistance in wheat.     

Induction of <Emphasis Type="Italic">Fusarium</Emphasis> wilt (<Emphasis Type="Italic">Fusarium oxysporum</Emphasis> f. sp. <Emphasis Type="Italic">pisi</Emphasis>) resistance in garden pea using induced mutagenesis and in vitro selection techniques

Wilt caused by Fusarium oxysporum f. sp. pisi is a serious production constraint for peas worldwide. An attempt was made to isolate wilt-resistant mutants in two susceptible pea genotypes, Arkel and Azad P-1, employing induced mutagenesis and in vitro selection techniques. Two thousand seeds of each genotype were mutagenized either with ethyl methane sulfonate (EMS, 0.2% and 0.3%) or gamma rays (5-22.5 kR) in ⁶⁰Co gamma cell for three consecutive years. Screening of different mutagenized populations under wilt-sick plots resulted in the isolation of 25 mutants exhibiting complete or enhanced wilt resistance compared to parental genotypes. Five of these wilt-resistant mutants also outperformed the susceptible background genotypes in terms of yield and other horticultural traits. Efforts were also made to isolate wilt-resistant regenerants from callus cultures exhibiting insensitivity to culture filtrate (CF) of F. oxysporum f. sp. pisi. A total of 250 regenerants (R ₀) were obtained from CF-insensitive calli selected from medium supplemented with 20% culture filtrate. When evaluated in artificially inoculated sick plots, only five R ₂ lines obtained from the regenerants exhibited enhanced wilt resistance compared to parental cultivars. However, the selected lines did not exhibit resistance levels equivalent to those shown by wilt-resistant lines isolated through in vivo mutagenesis. To conclude, induced mutagenesis through irradiation and EMS treatments exhibited superiority over in vitro selection for inducing wilt resistance in peas.     

Performance of various grapefruit (<Emphasis Type=\"Italic\">Citrus paradisi</Emphasis> Macf.) and pummelo (<Emphasis Type=\"Italic\">C. maxima</Emphasis> Merr.) cultivars under the dry tropic conditions of Mexico

Grapefruit growers in the tropics require information about existing and new citrus cultivars with high productivity potential. The objective of this study was to determine the growth, yield, and fruit quality performance of seven pigmented and four white grapefruit cultivars under the dry tropic conditions of Colima, Mexico. The trees were budded on sour orange (Citrus aurantium L.) rootstock and planted at a distance of 8 × 4 m. ‘Oroblanco’ and ‘Marsh Gardner’ white-fleshed grapefruit cultivars and ‘Chandler’, a pink-fleshed pummelo, were the largest trees with the greatest height (5.0–5.6 m), canopy diameter (6.2–6.3 m), trunk diameter (21.9–23.3 cm), and canopy volume (109–123 m³). Lower height (4.3–4.8 m) and canopy volume (73–96 m³), but with similar canopy diameter to the previously mentioned cultivars, were recorded for the remaining pigmented cultivars. ‘Chandler’ pummelo and four pigmented grapefruit cultivars (‘Shambar’, ‘Río Red’, ‘Ray Ruby’, and ‘Redblush #3’) had yearly productions of 34.8, 34.9, 34.1, 32.7, and 30.6 ton ha⁻¹, respectively. The most productive white grapefruit cultivar was ‘Marsh Gardner’ (30.5 ton ha⁻¹). Grapefruit cultivars having the largest fruit size showed a higher inverse relationship between fruit weight and yield than those with small fruit. Most genotypes had higher values of fruit weight, juice content, and maturity index than those required by the local market. The most promising grapefruit cultivars based on their acceptable growth, yield superior to 30 ton ha⁻¹, and acceptable fruit color were ‘Río Red’, ‘Shambar’, ‘Ray Ruby’, and ‘Redblush #3’.     

Resistance of barley variety ‘Venezia’ and its reflection in the <Emphasis Type="Italic">Blumeria graminis</Emphasis> f. sp. <Emphasis Type="Italic">hordei</Emphasis> population

Genetic resistance is an efficient and environmentally acceptable way of limiting the damaging effects of plant pathogens on yield and quality of crops. Tests of winter barley variety Venezia revealed an unknown resistance to all tested Blumeria graminis f. sp. hordei isolates. Response type arrays (RTAs) obtained here were created using common avirulent (RT 0) isolates and virulent (RT 4) isolates that first appeared in 2011. RTA of Venezia was identical to RTAs of six other varieties, but differed from RTAs of all other previously tested varieties. Venezia was the first variety to be registered with this resistance, and it is recommended that the resistance be designated Ve. Among 905 isolates randomly collected from the Czech aerial pathogen populations from 2009 to 2015, 13 contained Ve virulence. Each of the isolates differed from the others and thus belonged to different pathotypes. Seven of these 13 pathotypes were collected in the western region of the Czech Republic in an area close to Germany, where Venezia was grown. This finding could support the hypothesis that pathotypes virulent to Venezia have migrated from Germany into the Czech Republic.     

Development and characterization of two new <Emphasis Type=\"Italic\">Triticum aestivum</Emphasis>–<Emphasis Type=\"Italic\">Dasypyrum</Emphasis><Emphasis Type=\"Italic\">villosum</Emphasis> Robertsonian translocation lines T1DS·1V#3L and T1DL·1V#3S and their effect on grain quality

Dasypyrum villosum (L.) Candargy is a diploid, wild relative of bread wheat (Triticum aestivum L.). Previous studies showed that D. villosum chromosome 1V has genes that encode seed storage proteins that may be used to enhance the grain quality of bread wheat. As a first step in genetic transfer, the present study was initiated to develop compensating Robertsonian translocations involving wheat chromosome 1D and D. villosum chromosome 1V and to analyze their effects on grain quality. A monosomic 1D stock was crossed with the disomic addition stock DA1V#3 and the double monosomic plants (20″ + 1D′ + 1V#3′) were self pollinated. Two co-dominant STS markers (BE499250 and BE591682) polymorphic for the short arm of 1V#3S and two dominant STS markers (BE518358 and BE585781) polymorphic for the long arm of 1V#3L were developed to screen a large number of progeny to identify plants that had only the 1V#3S or 1V#3L arms. Five compensating Robertsonian heterozygous translocations, two (plants #56 and #83) for the short arm (T1DL·1V#3S) and three (plants #7, #123, and #208) for the long arm (T1DS·1V#3L) were identified from 282 F₂ plants and confirmed by genomic in situ hybridization and C-banding analyses. Two homozygous translocations T1DL·1V#3S (plants #14 and #39) were identified from 52 F₃ plants derived from F₂ plant #83. Four homozygous translocations T1DS·1V#3L (plants #3, #22, #29, and #30) were identified from 68 F₃ plants derived from F₂ plant #208. The homozygous translocation T1DL·1V#3S had a significantly higher (37.4 ml) and T1DS·1V#3L had significantly lower (10 ml) Zeleny sedimentation values compared to Chinese Spring wheat (30.7 ml). Our results showed that 1V#3S increased gluten strength and enhanced wheat quality, but 1V#3L decreased gluten strength and did not enhance wheat quality.     

Genotype × environment interactions in populations possessing <Emphasis Type="Italic">Ga1</Emphasis>-<Emphasis Type="Italic">s</Emphasis> and <Emphasis Type="Italic">ga1</Emphasis> alleles for cross incompatibility in maize

Use of cross incompatibility in corn (Zea mays L.) by the Ga1-s allele may reduce cross-fertilization in specialty and conventional organic corn with pollen from genetically-modified (GM) corn. For effective use, information about environment, and genotype × environment effects on cross-fertilization by ga1 as well as heritability of cross incompatibility in maize is necessary. Our objective was to obtain this information. Four population pairs differing in their genotype at ga1 were evaluated for cross incompatibility with ga1 pollen in different environments. Populations were derived by crossing the recurrent parents B116, PHG35, ARZM16035:S19, and (CHZM05015:Mo17)Mo17 to Ga1-s donor parent Mo508W/Mo506W. Two replicates of each treatment were grown in the center of 952 m² fields planted with purple corn as an adventitious source of ga1/ga1 pollen. Open pollination was allowed and the amount of cross-fertilization estimated by averaging the percentage of purple seeds. Environment and genotype × environment effects were not significant. Contrasts to evaluate differences in cross-fertilization between Ga1-s and ga1 populations revealed that mean percentages of cross-fertilization in Ga1-s populations of B116, ARZM16035:S19, and (CHZM05015:Mo17)Mo17 were significantly lower than in ga1 populations. The estimated broad-sense heritability on an entry-mean basis for cross incompatibility was 0.81. Results suggest differences in genotype at ga1 played a major role in cross-fertilization of populations differing in their genotype at the ga1 locus. Incompatibility may be selected effectively over different environments and the Ga1-s system may be of value to reduce cross-fertilization with GM corn pollen.     

Genetic diversity of feral alfalfa (<Emphasis Type=\"Italic\">Medicago</Emphasis> <Emphasis Type=\"Italic\">sativa</Emphasis> L.) populations occurring in Manitoba,Canada and comparison with alfalfa cultivars: an analysis using SSR markers and phenotypic traits

Feral populations of cultivated crops may act as reservoirs for novel traits and aid in trait movement across the landscape. Knowledge on the genetic diversity of feral populations may provide new insights into their origin and evolution and may help in the design of efficient novel trait confinement protocols. In this study, the genetic diversity of 12 feral alfalfa (Medicago sativa) populations originating from southern Manitoba (Canada) and 10 alfalfa cultivars and a M. falcata germplasm were investigated using eight SSR markers (i.e., microsatellites) and 14 phenotypic traits. We found that the genetic diversity observed in feral populations was similar to the diversity detected among the 10 cultivars. Analysis of molecular variance revealed that there was great genetic variation within (99.8%) rather than between different feral populations. Cluster analysis (unweighted pair-group method using arithmetic average) revealed no differentiation between feral populations and cultivars for neutral loci. High levels of population differentiation for phenotypic traits (and not for neutral markers) suggest the occurrence of heterogeneous selection for adaptive traits. The phenotypic traits we studied did not distinctly separate feral populations from cultivars but there was evidence of natural selection in feral populations for traits including winter survivability, rhizome production, and prostrate growth habit. Our results suggest that feral alfalfa populations need to be considered in the risk assessment of alfalfa containing novel genetically modified (GM) traits. Further, feral alfalfa populations may be regarded as a source of new germplasm for plant improvement.     

Identification of α-gliadin genes in <Emphasis Type=\"Italic\">Dasypyrum</Emphasis> in relation to evolution and breeding

To better understand molecular evolution of the large α-gliadin gene family and provide a potential value for wheat quality improvement, total 32 α-gliadin gene sequences were isolated from the two Dasypyrum species, D. villosum. (L.) Candargy and D. breviaristatum (Lindb. F.) Frederisksen. Twelve of 32 sequences contained the in-frame stop condons were predicted to be pseudogenes, suggesting the high variation of gliadin genes in Dasypyrum genome. There are five D. breviaristatum α-gliadin sequences present additional cysteine residues. Four peptides which have been identified as T cell stimulatory epitopes in celiac disease (CD) patients through binding to HLA-DQ2/8 were searched to all Dasypyrum α-gliadin gene sequences, and we found that the distribution of the epitopes varied between Dasypyrum genomes. Phylogenetic analysis of the Dasypyrum α-gliadin genes indicated that the sequences from D. breviaristatum displayed higher variation than those from D. villosum, and the genomic differentiation occurred between the two Dasypyrum species. Moreover, the promoter region of the Dasypyrum α-gliadin genes consisted of four different lengths, indicative of the retrotransposons involving the evolution of the gliadin gene promoters. Based on the specific sequences of the Dasypyrum α-gliadin promoter region, we produced sequence-characterized amplified region (SCAR) markers, and localized the Dasypyrum α-gliadin genes on chromosome 6 VS. The SCAR markers can be used to target the introgression of Dasypyrum α-gliadin genes in wheat–Dasypyrum derivatives.     

Mapping quantitative trait loci for cottonseed oil,protein and gossypol content in a <Emphasis Type=\"Italic\">Gossypium hirsutum</Emphasis> × <Emphasis Type=\"Italic\">Gossypium barbadense</Emphasis> backcross inbred line population

Cotton is one of the most important oil-producing crops and the cottonseed meal provides important protein nutrients as animal feed. However, information on the genetic basis of cottonseed oil and protein contents is lacking. A backcross inbred line (BIL) population from a cross between Gossypium hirsutum as the recurrent parent and G. barbadense was used to identify quantitative trait loci (QTLs) for cottonseed oil, protein, and gossypol contents. The BIL population of 146 lines together with the two parental lines was tested in the same location for three years in China. Based on a genetic map of 392 SSR markers and a total genetic distance of 2,895.2 cM, 17 QTLs on 12 chromosomes for oil content, 22 QTLs on 12 chromosomes for protein content and three QTLs on two chromosomes for gossypol content were detected. Seed oil content was significantly and negatively correlated with seed protein content, which can be explained by eight QTLs for both oil and protein contents co-localized in the same regions but with opposite additive effects. This research represents the first report using a permanent advanced backcross inbred population of an interspecific hybrid population to identify QTLs for seed quality traits in cotton in three environments.     

Evaluation of <Emphasis Type="Italic">in vitro</Emphasis> water stress tolerance among EMS — Induced variants of banana (<Emphasis Type="Italic">Musa</Emphasis> spp., AAA), using “morphological,physiological and molecular” traits

Water stress is a serious environmental restriction to banana productivity. Hence, the objective of this study was to employ in vitro mutagenesis in selection and characterization of drought tolerant lines in banana. In vitro culture responses of ethyl methanesulphonate induced variants of banana cultivars, ‘Berangan Intan’ and ‘Berangan’ were assessed concerning morphological, physiological and molecular characteristics involving mutated shoot tips on MS medium supplemented with 30 g L⁻¹ PEG. The results showed that water stress tolerant lines could be obtained from induced variations. Variants L_2–5 and L_1–5 showed the highest number of leaves per shoot (2.37 and 2.06, respectively) and the lowest were recorded in the parental lines L_1-1 and L_2-1 (0.81 and 0.93, respectively). Fresh weight and shoot vigor rate indicated the maximum increase in the water stress tolerant lines compared with susceptible and non-mutated parental lines. L_2–5 exhibited the most increase in the chlorophyll and the most reduction in H₂O₂ and MDA contents when exposed to water stress. Under PEG treatment, proline and relative water content was enhanced in L_1–5, L_2–5, L_2–6, L_1–6, L_2–3, L_2–4, and L_1–4. RAPD analysis revealed polymorphism (18.35 and 21.48%) among variants derived from ‘Berangan Intan’ and ‘Berangan’, respectively. The amplified fragments generated by primers opc01, opc04, opa11, and opa20 observed to be specific for L_2–5 and L_1–5 as more tolerant followed by L_2–3, L_1–4, L_2–6, and L_1–6 as moderately tolerant lines against water stress. This study demonstrates the application of in vitro mutagenesis in selection of water stress tolerant lines of banana as a convenient, cheap, and rapid technique.