The response of faba bean to the application of four rates of gypsum (0, 2.5, 5.0, 10.0 t ha−1) to a non-saline, alkaline sodic soil was measured in terms of grain yield, dry matter (DM) production, N accumulation and
the proportional dependence of the legume on symbiotic N2 fixation (Patm). A yield-independent, time-integrated 15N-dilution model was used to estimate symbiotic dependence. A significant decrease in the exchangeable sodium percentage and
significant increases in exchangeable Ca++ and the Ca++:Mg++ ratio in the 0–10-cm soil layer were measured 30 months after application of 10 t ha−1 gypsum. Despite low and erratic rainfall during crop growth, faba bean DM and N uptake responded positively to gypsum application.
The symbiotic dependence of the legume at physiological maturity was little affected by sodicity (Patm = 0.74 at zero gypsum and 0.81–0.82 at 2.5–10 t ha−1 gypsum). The increase in fixed N due to gypsum application was mainly due to increases in legume DM and total N uptake. At
10 t ha−1 of gypsum, faba bean fixed more than 200 kg N ha−1 in above-ground biomass. 相似文献
This study aimed to investigate the effect of inoculation with plant growth-promoting Rhizobium and Pseudomonas species on NaCl-affected maize. Two cultivars of maize (cv. Agaiti 2002 and cv. Av 4001) selected on the basis of their yield
potential were grown in pots outdoors under natural conditions during July. Microorganisms were applied at seedling stage
and salt stress was induced 21 days after sowing and maintained up to 50% flowering after 120 days of stress. The salt treatment
caused a detrimental effect on growth and development of plants. Co-inoculation resulted in some positive adaptative responses
of maize plants under salinity. The salt tolerance from inoculation was generally mediated by decreases in electrolyte leakage
and in osmotic potential, an increase in osmoregulant (proline) production, maintenance of relative water content of leaves,
and selective uptake of K ions. Generally, the microbial strain acted synergistically. However, under unstressed conditions,
Rhizobium was more effective than Pseudomonas but under salt stress the favorable effect was observed even if some exceptions were also observed. The maize cv. Agaiti
2002 appeared to be more responsive to inoculation and was relatively less tolerant to salt compared to that of cv. Av 4001. 相似文献
Neglected and underutilized species often play a vital role in securing food and livestock feed, income generation and energy
needs of rural populations. In spite of their great potential little attention has been given to these species. This increases
the possibility of genetic erosion which would further restrict the survival strategies of people in rural areas. Ziziphus spina-christi is a plant species that has edible fruits and a number of other beneficial applications that include the use of leaves as
fodder, branches for fencing, wood as fuel, for construction and furniture making, and the utilization of different parts
e.g. Fruits, leaves, roots and bark in folk medicine. Moreover, the plant is adapted to dry and hot climates which make it
suitable for cultivation in an environment characterized by increasing degradation of land and water resources. Lack of research
in Z. spina-christi hinders its successful improvement and promotion. Therefore, studies are needed to fully exploit this species. This article
aims at summarizing information on different aspects of Z. spina-christi to stimulate interest in this crop which is of importance in Sudan and other countries of the semi-arid tropics.
Maize (Zea mays L.) and Asian rice (Oryza sativa L.), two most important cereals for human nutrition, have undergone strong artificial selection during a long period of time. Currently, a number of genes with stronger signals of selection have been identified through combining genomic and population genetic approach, but research on artificial selection of maize and Asian rice is scarcely done from the perspective of phenotypic difference of a number of agronomic traits. In this study, such an investigation was carried out on the basis of 179 published studies about phenotypic quantitative trait locus (QTL) mapping of Zea and Oryza species via QTL sign test. At the overall level, the proportions of antagonistic QTLs of Zea and Oryza species were 0.2446 and 0.2382 respectively, deviating significantly from neutrality. It indicated that these two genera have undergone similar selection strength during their evolutionary process. A previous study showed that 4 traits undergoing the directional selection during domestication were identified in Asian rice via QTL sign test, and 16 individual traits in Asian rice and 38 ones in maize that newly detected in this study deviated significantly from neutrality as well, demonstrating the dominant influence of artificial selection on them. Moreover, analysis of different categories of cross type including O. sativa × Oryza rufipogon (perennial and annual forms) crosses, maize × teosinte (Zea mays subsp. parviglumis) crosses, O. sativa × O. sativa crosses, and maize × maize crosses showed that their proportions of antagonistic QTLs were 0.1869, 0.1467, 0.2649, and 0.2618 respectively. These results revealed that selection strength of domestication is significantly stronger than that of modern genetic improvement. However, interestingly, the proportion of antagonistic QTLs (0.1591) in maize × maize with long-term selection was very similar to that (0.1467) in the maize × teosinte (Zea mays subsp. parviglumis) crosses. It suggested that some favorable traits could be cultivated within a few decades if we carry out strong selection. In addition, the proportions of antagonistic QTLs of the widely cultivated hybrids of rice (Minghui 63 × Zhenshan 97) and maize (Zheng 58 × Chang 7-2) in China were 0.309 and 0.3472 respectively. It suggested that selection during modern genetic improvement has significantly acted on them. 相似文献
Few studies have been conducted to evaluate the effects of mixtures of chemicals in terrestrial environment. Thus, it seems
important to evaluate if the combined application of pesticides currently used in agricultural fields may pose a risk to terrestrial
plants. 相似文献
Calamintha nepeta and Micromeria thymifolia have been traditionally used in the Mediterranean area as condiments and medicinal plants for a long time. Whereas in parts of Italy C. nepeta (special recipes have been developed in Lazio and Tuscany) is also an established garden plant showing different evolutionary products and their interaction among each other and the wild progenitor, M. thymifolia is being developed into a new crop plant. Both plants and their uses are described with regard to Italy. There is a marked tendency to broaden the use of condiments and spices which results in new crop plants which have to be documented and elaborated in further studies. Many species of Labiatae are predisposed to use by man and new items can be found even in areas which have to be considered as well studied. 相似文献
The aim of this study was to identify the group of highly polymorphic microsatellite markers for the identification of six
pear cultivars (P.communis) and two individuals of wild pear (P. pyraster). From among 40 tested SSR markers, 19 were selected to profile genetic diversity in pear genotypes due to high polymorphisms.
These markers showed high heterozygosity levels (0.5–1) and, on average, 6.4 alleles per marker were found. The set of microsatellite
markers employed in this study demonstrated usefulness of microsatellite markers for the identification of pear genotypes.
The examined wild forms were represented in this study by only two individuals of P. pyraster. It can be assumed that these forms were distinctly different from the cultivated pear cultivars. 相似文献
Genetic diversity of populations stored ex situ or in situ can be altered due to the management practices they are subjected
to. In this paper, we compare populations of two common bean (Phaseolus vulgaris L.) landraces grown on farms with material
collected from the same farms and now kept in two ex situ collections (CIAT and REGEN) with the purpose to monitor any changes
that have occurred due to ex situ conservation. The diversity was measured using seven bean microsatellite markers. Further
phenotypic and developmental traits were registered in a field experiment. Compared with the in situ populations, the ex situ
ones had a lower level of gene diversity and we suggest that this is due to the regeneration process. Most of the phenotypic
traits did not differ significantly between ex situ and in situ populations, although for yield and 100-seed weight, the CIAT
material showed significant lower values. We assume that these populations have gone through an adaptational change. Overall,
the conservation ex situ has been successful in maintaining the majority of the adaptations found in the landraces studied,
however, the probable loss of genetic diversity that we have observed, suggest that protocols for the regeneration process
must be carefully worked out if the majority of alleles are to be preserved for the future. This study also highlights the
complementarity of ex situ and in situ conservation methods in order to preserve landrace adaptations and to capture new,
useful diversity generated in in situ populations. 相似文献
The diversity among 269 rhizobia isolated from naturally occurring root nodules of soybean collected from two different agro-ecological
regions of India, based on RFLP and sequences of the intergenic spacer (IGS) between the 16S and 23S rRNA genes, growth rate,
and indole acetic acid production, revealed their significant, site-dependent genomic diversity. Among these bacteria, nine
IGS genotypes were identified with two endonucleases. They were distributed into five divergent lineages by sequence analysis
of each IGS representative strain, i.e., (1) comprising IGS genotypes I, II, III, and reference Bradyrhizobium yuanmingense; (2) with genotype IV and strains of unclassified bradyrhizobia genomic species; (3) including genotypes V, VI, and Bradyrhizobium liaoningense; (4) with IGS genotype VII and Bradyrhizobium elkanii strains; and (5) comprising IGS genotypes VIII, IX, and different Ensifer genus bacteria. Host-specificity test revealed that all rhizobia-nodulated soybean and cowpea and only part of them formed
nodules on Arachis hypogeae and Cajanus cajan. The great diversity of soybean nodulators observed in this study emphasises that Indian soil is an important reservoir of
nitrogen-fixing rhizobia. 相似文献
This study reports for the first time the presence of diazotrophic bacteria belonging to the genera Achromobacter and Zoogloea associated with wheat plants. These bacterial strains were identified by the analysis of 16S rDNA sequences. The bacterium
IAC-AT-8 was identified as Azospirillum brasiliense, whereas isolates IAC-HT-11 and IAC-HT-12 were identified as Achromobacter insolitus and Zoogloea ramigera, respectively. A greenhouse experiment involving a non-sterilized soil was carried out with the aim to study the endophytic
feature of these strains. After 40 days from inoculation, all the strains were in the inner of roots, but they were not detected
in soil. In order to assess the location inside wheat plants, an experiment was conducted under axenic conditions. Fifteen
days after inoculation, preparations of inoculated plants were observed by the scanning electron microscope, using the cryofracture
technique, and by the transmission electron microscope. It was observed that all isolates were present on the external part
of the roots and in the inner part at the elongation region, in cortex cells, but not in the endodermis or in the vascular
bundle region. No colonizing bacterial cells were observed in wheat leaves. 相似文献
V. rhomboidea is a wild Vigna species that is a potential source of genes for pubescence which could be incorporated into
cultivated cowpea for insect pests resistance. Due to the lack of reliable records on the crossability and gene pool relationships
between V. rhomboidea and cowpea, crossing trials were conducted in the screenhouse to observe if V. rhomboidea is reciprocally
crossable (compatible) with cowpea. Crossability of V. rhomboidea (as seed parent) with cowpea (as pollen parent) was, for
the first time, successfully achieved at the rate of 5.7% from 1145 crosses. Reciprocal crosses with cowpea as seed parent
and V. rhomboidea pollen parent gave an average of 22.6% pod set from 2299 crosses. It is concluded that V. rhomboidea is
reciprocally compatible with cowpea. This implies that V. rhomboidea belongs to the primary gene pool of cowpea. 相似文献
Trigeneric hybrids may help establish evolutionary relationships among different genomes present in the same cellular-genetic
background, and also offers the possibility to transfer different alien characters into cultivated wheat. In this study, a
new trigeneric hybrid involving species from the Triticum, Psathyrostachys and Secale was synthesized by crossing wheat-P. huashanica amphiploid (PHW-SA) with wheat-S. cereale amphiploid (Zhongsi 828). The crossability of F1 hybrid was high with 35.13%, and the fertility was 41.95%. The morphological characteristics of F1 plants resembled the parent Zhongsi 828. The trigeneric hybrids pollen mother cells (PMCs) regularly revealed averagely 19.88
univalents, 9.63 ring bivalents, 3.97 rod bivalents, 0.60 trivalents and 0.03 tetravalents per cell. Multivalents consisted
of trivalents and tetravalents can be observed in 52.7% of cells. A variation of abnormal lagging chromosome, micronuclei
and chromosome bridge were formed at anaphase I and telophase II. The mean chromosomes number of F2 progenies was 2n = 46.13, and the distribution range was 42–53. GISH results revealed that most F2 plants had 6–12 S. cereale chromosomes, and only 0–2 P. huashanica chromosomes were detected. The results indicated that S. cereale chromosomes can be preferentially transmitted in the F2 progenies of trigeneric hybrid than P. huashanica chromosomes. A survey of disease resistances revealed that the stripe rust resistance from the PHW-SA were completely expressed
in the F1 and some F2 plants. The trigeneric hybrid could be a useful bridge for the transference of P. huashanica and S. cereale chromatins to common wheat. 相似文献
Paracetamol, the most widely and globally used analgesic and antipyretic, is easily accumulated in aquatic environments. In the present study, the biodegradation of paracetamol in different media (one for general growth, one specific for sulfate reducing bacteria, a mineral salts medium and municipal wastewater) inoculated with two types of sludge (from anaerobic lagoon and from oxidation ditch) under different oxygenic conditions (anoxic; moderate oxygenation in open flasks and high oxygenation by aeration) was investigated. In addition, bacteria with relative abundances increasing simultaneously with paracetamol degradation, when this drug was the only carbon source, thus with a putative role in its degradation, were identified using 16S rRNA gene sequences. The results show that aerobic microorganisms had a major role in the degradation of paracetamol, with 50 mg/L totally removed from municipal wastewater after 2 days incubation with aeration, and that the metabolites 4-aminophenol and hydroquinone plus one compound not identified in this work were produced in the process. The identification of bacteria with a role in the degradation of paracetamol revealed a strain from genus Pseudomonas with the highest final relative abundance of 21.2%, confirming previous works reporting strains of this genus as paracetamol decomposers. Besides, genera Flavobacterium, Dokdonella and Methylophilus were also in evidence, with initial relative abundances of 1.66%, 1.48 and 0.00% (not detected) in the inoculum and 6.91%, 3.80 and 3.83% after incubation, respectively. Therefore, a putative role of these genera in paracetamol biodegradation is suggested for the first time.
The present study was conducted to isolate and characterize rhizobial strains from root nodules of cultivated legumes, i.e. chickpea, mungbean, pea and siratro. Preliminary characterization of these isolates was done on the basis of plant infectivity test, acetylene reduction assay, C-source utilization, phosphate solubilization, phytohormones and polysaccharide production. The plant infectivity test and acetylene reduction assay showed effective root nodule formation by all the isolates on their respective hosts, except for chickpea isolate Ca-18 that failed to infect its original host. All strains showed homology to a typical Rhizobium strain on the basis of growth pattern, C-source utilization and polysaccharide production. The strain Ca-18 was characterized by its phosphate solubilization and indole acetic acid (IAA) production. The genetic relationship of the six rhizobial strains was carried out by random amplified polymorphic DNA (RAPD) including a reference strain of Bradyrhizobium japonicum TAL-102. Analysis conducted with 60 primers discriminated between the strains of Rhizobium and Bradyrhizobium in two different clusters. One of the primers, OPB-5, yielded a unique RAPD pattern for the six strains and well discriminated the non-nodulating chickpea isolate Ca-18 from all the other nodulating rhizobial strains. Isolate Ca-18 showed the least homology of 15% and 18% with Rhizobium and Bradyrhizobium, respectively, and was probably not a (Brady)rhizobium strain. Partial 16S rRNA gene sequence analysis for MN-S, TAL-102 and Ca-18 strains showed 97% homology between MN-S and TAL-102 strains, supporting the view that they were strains of B. japonicum species. The non-infective isolate Ca-18 was 67% different from the other two strains and probably was an Agrobacterium strain. 相似文献
Maize (Zea mays L.) is a tropical crop with low tolerance to cold conditions and has to be planted late in temperate areas due to low temperatures.
The objective of this research was to identify new cold tolerant populations among the European germplasm useful for improving
adaptation to early sowing. For that, the European Union Maize Landraces Core Collection (EUMLCC) was evaluated under cold
conditions. After a preliminary screening of 95 populations the 11 populations with best germination and early growth under
cold conditions were multiplied and evaluated in a cold chamber and in early field sowings at two locations during 2 years.
The cold tolerant populations from the EUMLCC were not significantly different from the cold tolerant checks in the cold chamber.
In early field sowing, some EUMLCC populations had similar emergence than the commercial checks and the coldest tolerant hybrids,
and higher vigor than all the hybrids and the yield of some of the populations surpassed the yield of the cold tolerant hybrids.
Altogether, Aranga1 emerged as the most promising candidate as base population for improving adaptation to early sowing. 相似文献
The variation in 20 morphological and agronomical traits has been evaluated in a set of chickpea genetic resources from four
countries. Data indicated differences between accessions in leaf, flower, pod, and seed traits and characteristics, as well
as in vegetation period. Multivariate analyses of these data segregated chickpeas into groups. Polymorphism in seed glutelines
was absent, while variation in seed prolamines was very limited. DNA amplification patterns have been analyzed by semi-arbitrary
primers and by specific microsatellite primers. Only some of semi-arbitrary primers generated usable DNA banding patterns,
moreover interpretation of these patterns can be more or less difficult. On the contrary specific primers amplifying microsatellites
at the specific loci generated unambiguous and reproducible differences between chickpeas. 相似文献
Tepary bean is a highly abiotic stress tolerant orphan crop for which there has been limited research on its nutritional value and cooking characteristics. These are key aspects when considering the potential for broader adoption of tepary bean. Therefore, the goal of this study was to evaluate a large set of seed composition and cooking traits related to human nutrition using both landraces and breeding lines of domesticated tepary bean from replicated field trials and to compare the traits in tepary with those in common bean. Tepary bean showed reduced fat and ash concentration and higher sucrose concentration as compared to common bean. Of the twelve amino acids evaluated, only proline in one of the two trials was statistically different between the two species. There were statistically significant differences between tepary and common bean for the concentration of some elements in this study; however, the elemental concentrations fell within the range of those found for common bean in previous studies. The majority of tepary bean lines showed consistently short cooking times and a high percentage of seeds showed measurable water uptake, while some showed a hardshell trait (low water uptake) and longer cooking times. Principal component analysis on a subset of traits showed a distinct group of common beans and two tepary bean groups that were divided on the basis of several agronomic, cooking, and elemental composition traits. Tepary bean, as with other pulses, is a highly nutritious crop with the range of composition and cooking characteristics similar to those of common bean. The variability for seed composition and cooking traits found within tepary bean can be exploited for its improvement. 相似文献
In order to evaluate and compare the germplasm resources of wheat in Tibet, we analyzed the genetic diversity of 136 Triticum aestivum ssp. tibetanum Shao and 119 Tibetan wheat landraces (Triticum aestivum L.) by using Intron-Splice Junction (ISJ) primers. The results showed that polymorphism of PCR products were obtained by
33 primer combinations, which accounted for 11% of the 300 primer combinations produced by 26 ISJ primers. A total of 333
stable bands can be amplified from the T. aestivum ssp. tibetanum Shao and 243 bands were polymorphic, which accounted for 72.9% of the total bands. Tibetan wheat Landraces produced 316 stable
bands, of which 197 bands were polymorphic. The polymorphic bands accounted for 62.34% of the total bands produced from Tibetan
wheat landraces. The genetic diversity of T. aestivum ssp. tibetanum Shao was higher than that of Tibetan wheat landraces in Tibet, suggesting that T. aestivum ssp. tibetanum Shao can be used as important genetic resource for the breeding and genetic improvement of wheat in Tibet. Matrix (1, 0)
was generated according to the presence or absence of the bands produced from a particular wheat accession. Clustering and
principle coordinates analysis showed that T. aestivum ssp. tibetanum Shao and Tibetan wheat landraces were divided into two groups. We conclude that high polymorphisms produced by ISJ primers
can reflect the genetic diversity between T. aestivum ssp. tibetanum Shao and Tibetan wheat landraces. 相似文献
In Ethiopia, barley is generally grown in two different planting seasons per year: during the long rainy season (Meher) and the short rainy season (Belg). The aim of the present study was to assess for the first time the role of this ‘two-season system’ on the structure of
the genetic diversity of the Ethiopian barley landraces. We characterised 3,170 individual genotypes from 106 landrace populations
using eight morphological spike traits. The diversity within population was higher in the season where barley is more important
(Belg), and in general, where its cultivation is in larger plots because of weaker ‘competition’ with others crops. This indicates
that barley diversity has a complex relationship with variations in the surrounding agro-ecosystem. Overall, the divergence
between the two seasons was quite small (3.4%), suggesting that seed flow does not occur independently across the years within
the two seasons. This would affect the amount of mutations and historic recombination that have accumulated within these populations. 相似文献