Comparison of <Emphasis Type="Italic">Claviceps purpurea</Emphasis> populations originated from experimental plots or fields of rye

Background  

The phytopathogenic ascomycete Claviceps purpurea causes the ergot — serious disease of rye and grasses. Its sclerotia containing toxic ergot alkaloids decrease a quality of cereal grain. The fungus infects young, unfertilized ovaries of the hosts. Due to the very short time in which infection can occur, growth rate of mycelium can play some role in the infection process. Resistance genes to C. purpurea have not been found so far.     

Genetic variation and clonal structure of the rare,riparian shrub <Emphasis Type="Italic">Spiraea virginiana</Emphasis> (Rosaceae)

Genetic diversity is often considered important for species that inhabit highly disturbed environments to allow for adaptation. Many variables affect levels of genetic variation; however, the two most influential variables are population size and type of reproduction. When analyzed separately, both small population size and asexual reproduction can lead to reductions in genetic variation, although the exact nature of which can be contrasting. Genetic variables such as allelic richness, heterozygosity, inbreeding coefficient, and population differentiation have opposite predictions depending upon the trait (rarity or clonality) examined. The goal of this study was to quantify genetic variation and population differentiation in a species that resides in a highly stochastic environment and is both rare and highly clonal, Spiraea virginiana, and to determine if one trait is more influential genetically than the other. From populations sampled throughout the natural range of S. virginiana, we used microsatellite loci to estimate overall genetic variation. We also calculated clonal structure within populations, which included genotypic richness, evenness, and diversity. Gene flow was investigated by quantifying the relationship between genetic and geographic distances, and population differentiation (θ) among populations. Observed heterozygosity, genotypic richness, and inbreeding coefficients were found to be representative of high clonal reproduction (averaging 0.505, 0.1, and –0.356, respectively) and the number of alleles within populations was low (range = 2.0–3.6), being more indicative of rarity. Population differentiation (θ) among populations was high (average = 0.302) and there was no relationship between genetic and geographic distances. By examining a species that exhibits two traits that both can lead to reduced genetic variation, we may find an enhanced urgency for conservation. Accurate demographic counts of clonal species are rarely, if ever, possible and genetic exploration for every species is not feasible. Therefore, the conclusions in this study can be potentially extrapolated to other riparian, clonal shrubs that share similar biology as S. virginiana.     

Population genetic structure of the endangered and endemic medicinal plant <Emphasis Type="Italic">Commiphora</Emphasis><Emphasis Type="Italic">wightii</Emphasis>

Commiphora wightii is a medicinally important endangered species endemic to the Thar Desert of Rajasthan, India and adjoining areas of Pakistan. The populations of this species are declining sharply because of its extensive use as a natural herb. Random amplified polymorphic DNA analysis was conducted to find the genetic variation among 7 populations of C. wightii. Of the 100 random primers screened, 44 primers yielded 220 loci. Statistical analysis indicated low genetic diversity (H _pop = 0.0958; I = 0.1498; mean polymorphic loci = 14.28%), and high genetic differentiation among the populations (G _ST = 0.3990; AMOVA Φ _ST of 0.3390; Bayesian θ ^(II) = 0.3002). The low genetic diversity may be due to geographic isolation and restricted gene flow (N _m = 0.7533) between the fragmented populations. Unsustainable utilization of the plant has fragmented the population continuum which served the purpose of genetic exchange between populations. Mantel’s test was performed which revealed a highly significant positive correlation between genetic and geographic distance (r ² = 0.614, P = 0.023) among the populations studied. Low variation can also be attributed to poor seed setting and the slow growth pattern of the species, which is also an apomict. In UPGMA dendrogram the Commiphora wightii samples were divided into two major and one minor cluster. These findings can serve as a guide to preserving the genetic resources of this medicinal plant species.     

Early development and larval behaviour of two clingfishes, <Emphasis Type="Italic">Lepadogaster purpurea</Emphasis> and <Emphasis Type="Italic">Lepadogaster lepadogaster</Emphasis> (Pisces: Gobiesocidae)

The recent revision on the taxonomic status of Lepadogaster lepadogaster resulted in the division of this species into L. lepadogaster and L. purpurea, the clarification of each species’ distribution ranges and the elimination of L. zebrina (now in synonymy with L. lepadogaster). This new taxonomic status led to the need of clarifying the early development of the two species. Embryonic development lasted 21 days in L. purpurea at a mean temperature of 14.2°C, and 16 days in L. lepadogaster at a mean temperature of 16.5°C. Newly hatched larvae of both species measured 5.2 mm, had the mouth and anus opened, pigmented eyes and almost no yolk. At hatching and throughout development the two species can be distinguished by the ventral pigmentation which is absent in L. purpurea. The change to a benthic mode of life was gradual in both species, with larvae increasingly spending more time close to the bottom until definitely settling. Larval development lasted 33 days in L. purpurea at a mean temperature of 14.6°C and 18 days in L. lepadogaster at a mean temperature of 16.5°C. Locomotion and foraging behaviours are described for both species. L. lepadogaster showed a higher frequency of swimming and foraging behaviour when compared with L. purpurea.     

Genetic variation of wild litchi (<Emphasis Type="Italic">Litchi chinensis</Emphasis> Sonn. subsp. <Emphasis Type="Italic">chinensis</Emphasis>) revealed by microsatellites

Understanding the amount and distribution of genetic diversity in natural populations can inform the conservation strategy for the species in question. In this study, genetic variation at eight nuclear microsatellite loci was used to investigate genetic diversity and population structure of wild litchi (Litchi chinensis Sonn. subsp. chinensis). Totally 215 individuals were sampled, representing nine populations of wild litchi. All eight loci were polymorphic, with a total of 51 alleles. The expected heterozygosity in the nine populations ranged from 0.367 to 0.638 with an average value of 0.526. Inbreeding within wild litchi populations was indicated by a strong heterozygote defect. Significant bottleneck events were detected in the populations from Yunnan and Vietnam, which could be responsible for lower levels of genetic diversity in these populations. Measures of genetic differentiation (F _ST = 0.269) indicated strong differentiation among wild litchi populations. Significant correlation was found between genetic differentiation and geographical distance (r = 0.655, P = 0.002), indicating a strong isolation by distance in these populations. Bayesian clustering suggested genetic separation among three regional groups, namely, the western group, the central group and the eastern group. Some conservation strategies for wild litchi populations were also proposed based on our results.     

Genetic variation in populations of <Emphasis Type="Italic">Allothrombium pulvinum</Emphasis> (Acari: Trombidiidae) from Northern Iran revealed by mitochondrial <Emphasis Type="Italic">cox</Emphasis>I and nuclear rDNA <Emphasis Type="Italic">ITS</Emphasis>2 sequences

Allothrombium pulvinum Ewing is a common natural enemy of aphids and some other arthropods. So far, there are no studies that have addressed genetic variation of this predatory mite. We investigated genetic variation of A. pulvinum across its whole known range in Iran. A 410 bp portion of the mitochondrial cytochrome c oxidase subunit I gene (coxI) and 797–802 bp portion of the internal transcribed spacer 2 of rDNA (ITS2) were sequenced for 55 individuals from 11 populations, resulting in 12 and 26 haplotypes, respectively. In the coxI region, haplotype and nucleotide diversities varied among populations from 0.00 to 0.90 and from 0.0000 to 0.0110, respectively. In the ITS2 region they varied from 0.20 to 0.91 and from 0.0006 to 0.0023, respectively. For both gene regions the highest haplotype and nucleotide diversities were detected in population Mahmoud Abad from northern Iran. Statistically significant population differentiation (F _ST) was detected in most pair-wise population comparisons. The results of population differentiation for both gene regions were generally congruent indicating that A. pulvinum from Iran consists of genetically different populations. This suggests that A. pulvinum comprises at least two geographically distinct populations or even more than one species. This study is an initial step towards understanding genetic variation of A. pulvinum, a taxon for which little molecular information is available. More intensive sampling and analysis of additional DNA regions are necessary for more detailed classification of this taxon.     

<Emphasis Type="Italic">MEFV</Emphasis> heterogeneity in Turkish Familial Mediterranean Fever patients

Turkey is one of the few countries in the world where Familial Mediterranean Fever (FMF), an autoinflammatory disease caused by mutations in MEFV, the gene encoding pyrin, is not rare. Many interesting studies regarding the genetics of Familial Mediterranean Fever in Turkey have been already published. Despite that different MEFV genetic profiles have been revealed for Turkish FMF patients, deriving from different regions of Turkey, a systematic population genetics analysis has not been carried out yet. The present study aims to investigate the population genetics of MEFV in Turkish FMF patients so as to additionally facilitate the clinical interpretation of individualized genetic data. All relevant studies have been recruited by searching PubMed with the terms “MEFV”, “FMF”, and “Turkey”. Seven of them, including 3,061 FMF patients, contained all necessary data concerning allelic and genotypic frequencies of the 4 commonest MEFV mutations in Turkey (M694V, V726A, M680I, E148Q). From all 6,122 MEFV alleles analyzed, the M694V mutation was recognized in 15.6–52.2% (mean 29.3%), the V726A in 1.5–9.7% (mean 4.8%), the M680I in 1.5–15.5% (mean 7.6%), and the E148Q in 3.2–13.9% (mean 5.5%). Unidentified mutations ranged from 0–42.9% (mean 16.8%). No mutations were found in 0–54.5% (mean 36.0%) of the patients. The allelic and genotypic frequencies of the most frequent mutation (M694V) showed aberration of the Hardy–Weinberg law for all 7 populations studied. By application of the Arlequin 2.0 population genetics software, the Fixation index (F _ST) was found to be 0.09994, thus demonstrating that the observed variability is mainly within (90.006%) and not among (9.994%) populations (P < 0.00001). Moreover, the global test of differentiation demonstrated that every population differs from each other (P < 0.00325). Finally, the Ewens–Watterson test of selective neutrality yielded to statistical significance in only 3 populations. In conclusion, Turkish FMF patients are characterized by an increased genetic heterogeneity, explained by the intrapopulation differentiation. Thus, the regional origin should be regarded as a determining factor in the diagnosis of FMF in Turkish patients.     

DArT markers tightly linked with the <Emphasis Type="Italic">Rfc1</Emphasis> gene controlling restoration of male fertility in the CMS-C system in cultivated rye (<Emphasis Type="Italic">Secale cereale</Emphasis> L.)

The Rfc1 gene controls restoration of male fertility in rye (Secale cereale L.) with sterility-inducing cytoplasm CMS-C. Two populations of recombinant inbred lines (RIL) were used in this study to identify DArT markers located on the 4RL chromosome, in the close vicinity of the Rfc1 gene. In the population developed from the 541×2020LM intercross, numerous markers tightly linked with the restorer gene were identified. This group contained 91 DArT markers and three SCARs additionally analyzed in the study. All these markers were mapped in the distance not exceeding 6 cM from the gene of interest. In the second mapping population (541×Ot1-3 intercross), only 9 DArT markers located closely to the Rfc1 gene were identified. Five of these DArT markers were polymorphic in both populations.     

The identification of QTLs associated with the <Emphasis Type="Italic">in vitro</Emphasis> response of rye (<Emphasis Type="Italic">Secale cereale</Emphasis> L.)

This study was conducted in order to identify quantitative trait loci (QTLs) for the in vitro culture response of winter rye (Secale cereale L.) immature embryos and immature inflorescences. A genetic linkage map comprising 67 SSRs, 9 ISSRs, 13 SAMPLs, 7 RAPDs, 2 SCARs and one EST marker was created based on the analyses of 102 recombinant inbred lines from the cross between lines L318 (which has a good response in tissue cultures) and L9 (which is unable to regenerate plants from somatic tissues and anthers). The map spans 979.2 cM, and the average distance between markers is 9.9 cM. Two characteristics were evaluated: callus induction (CI) and somatic embryogenesis ability (SE). They were expressed as the percentage of immature embryos/inflorescences producing callus (designated ECI/ICI) and the percentage of explants producing somatic embryos (ESE/ISE). All the analysed traits showed continuous variation in the mapping population but a non-normal frequency distribution. We identified nine putative QTLs controlling the tissue culture response of rye, explaining up to 41.6% of the total phenotypic variation: two QTLs for ECI — eci-1, eci-2; 4 for ESE — ece-1, ese-2, ese-3, ese-4; 2 for ICI — ici-1, ici2; and 1 for ISE — ise-1. They were detected on chromosomes 1R, 4R, 5R, 6R and 7R.     

Contrasting population genetic structure and gene flow between <Emphasis Type="Italic">Oryza rufipogon</Emphasis> and <Emphasis Type="Italic">Oryza nivara</Emphasis>

The cross compatible wild relatives of crops have furnished valuable genes for crop improvement. Understanding the genetics of these wild species may enhance their further use in breeding. In this study, sequence variation of the nuclear Lhs1 gene was used to investigate the population genetic structure and gene flow of Oryza rufipogon and O. nivara, two wild species most closely related to O. sativa. The two species diverge markedly in life history and mating system, with O. rufipogon being perennial and outcrossing and O. nivara being annual and predominantly inbreeding. Based on sequence data from 105 plants representing 11 wild populations covering the entire geographic range of these wild species, we detected significantly higher nucleotide variation in O. rufipogon than in O. nivara at both the population and species levels. At the population level the diversity in O. rufipogon (Hd = 0.712; θ _sil = 0.0017) is 2–3 folds higher than that in O. nivara (Hd = 0.306; θ _sil = 0.0005). AMOVA partitioning indicated that genetic differentiation among O. nivara populations (78.2%) was much higher than that among O. rufipogon populations (52.3%). The different level of genetic diversity and contrasting population genetic structure between O. rufipogon and O. nivara might be explained by their distinct life histories and mating systems. Our simulation using IM models demonstrated significant gene flow from O. nivara to O. rufipogon, indicating a directional introgression from the annual and selfing species into the perennial and outcrossing species. The ongoing introgression has played an important role in shaping current patterns of genetic diversity of these two wild species. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Genetic analysis of two Portuguese populations of <Emphasis Type="Italic">Ruditapes decussatus</Emphasis> by RAPD profiling

The clam Ruditapes decussatus is commercially important in the south of Portugal. The random amplified polymorphic DNA (RAPD) technique was applied to assess the genetic diversity and population structure of two Portuguese populations occurring in the Ria Formosa (Faro) and the Ria de Alvor, respectively. Twenty-five individuals of each population were investigated by RAPD profiles. Genetic diversity within populations, measured by the percentage of polymorphic loci (%P), varied between 68.57% (Alvor) and 73.88% (Faro). Shannon’s information index (H) and Nei’s gene diversity (h) were 0.281 and 0.176, respectively, for the Alvor population and 0.356 and 0.234 for the Faro population. Overall, genetic variation within R. decussatus populations was high. The total genetic diversity (H _T) was explained by a low variation between populations (G _ST = 0.145), which is consistent with high gene flow (N _m = 2.9). The analysis of molecular variance (AMOVA) showed that 65% of variability is within populations and 35% between populations (Φ_PT = 0.345; P ≥ 0.001). The value of Nei’s genetic distance was 0.0881, showing a low degree of population genetic distance, despite the different geographic origin. This is the first study on the population genetics of R. decussatus by RAPD technique. The results may be useful for restocking programs and aquaculture.     

Genetic structure and gene flow in an endangered perennial grass, <Emphasis Type="Italic">Arctophila fulva</Emphasis> var. <Emphasis Type="Italic">pendulina</Emphasis>

Arctophila fulva var. pendulina is a rare endemic perennial grass confined to seashore and riverbank meadows around the Bothnian Bay, the northernmost part of the Baltic Sea. The number of A. fulva populations has decreased during the last few decades in Finland and Sweden, and nowadays there are only eight populations left in the drainage area of the Bothnian Bay. We investigated the distribution of genetic variation within and between six subpopulations in the largest remaining population at Liminka Bay, Finland, using amplified fragment length polymorphism (AFLP) markers. Relatively high amounts of variation were found in the subpopulations, the mean Nei’s expected heterozygosity being typical (0.267) for an outcrossing species. Despite the fact that no seedlings or viable seeds of A. fulva have been found in the previous field studies, the observed high genotypic diversity suggested that sexual reproduction has played an important role at some time during the history of the studied A. fulva population. Analysis of population structure revealed a low level of genotypic differentiation (Φ_ST=0.046) between subpopulations, and also significant sub-structuring within subpopulations. Isolation-by-distance between subpopulations was present on scales larger than 1 km. The overall pattern of genetic variation within and between subpopulations suggest that the population has characters of both stepping-stone and metapopulation models. Because our results suggested that subpopulations are more or less ephemeral, the conservation and management effort in this species should be targeted to conservation of the required habitat of the species instead of extant subpopulations.     

Polygenic inheritance of canopy wilting in soybean [<Emphasis Type="Italic">Glycine max</Emphasis> (L.) Merr.]

As water demand for agriculture exceeds water availability, cropping systems need to become more efficient in water usage, such as deployment of cultivars that sustain yield under drought conditions. Soybean cultivars differ in how quickly they wilt during water-deficit stress, and this trait may lead to yield improvement during drought. The objective of this study was to determine the genetic mechanism of canopy wilting in soybean using a mapping population of recombinant inbred lines (RILs) derived from a cross between KS4895 and Jackson. Canopy wilting was rated in three environments using a rating scale of 0 (no wilting) to 100 (severe wilting and plant death). Transgressive segregation was observed for the RIL population with the parents expressing intermediate wilting scores. Using multiple-loci analysis, four quantitative trait loci (QTLs) on molecular linkage groups (MLGs) A2, B2, D2, and F were detected (P ≤ 0.05), which collectively accounted for 47% of the phenotypic variation of genotypic means over all three environments. An analysis of the data by state revealed that 44% of the observed phenotypic variation in the Arkansas environments could be accounted for by these QTLs. Only the QTL on MLG F was detected at North Carolina where it accounted for 16% of the phenotypic variation. These results demonstrate that the genetic mechanism controlling canopy wilting was polygenic and environmentally sensitive and provide a foundation for future research to examine the importance of canopy wilting in drought tolerance of soybean.     

Germination,growth and survival of <Emphasis Type="Italic">Berberis thunbergii</Emphasis> DC. (Berberidaceae) and <Emphasis Type="Italic">Berberis thunbergii</Emphasis> var. <Emphasis Type="Italic">atropurpurea</Emphasis> in five natural environments

Germination, growth and survival of green Berberis thunbergii and its purple ornamental form, Berberis thunbergii var. atropurpurea, were compared in five natural environments (full sun meadow, edge of woods, moist woods, dry woods, pine woods) to determine whether these two forms have a similar ability to naturalize. Berberis thunbergii and Berberis thunbergii var. atropurpurea had similar germination rates of about 25% at the end of 3 years. Most of the seed germination occurred in year one (89%), with a small amount of additional germination in year two (10%), and even less in year three (1%). Greatest germination occurred in the moist woods and full sun meadow sites and the least occurred at the pine woods site. Germination was reduced in the pine woods environment by the thick leaf litter layer present there. Barberry seedling survival during the first year was only 22% and survival dropped to 11.3% by the end of 2 years. Purple barberry seedlings had a lower 2 year survival rate than green barberry. There was no difference in seedling growth between purple and green barberry seedlings, but surviving seedling growth rates at the five environments were comparable. Seedlings achieved maximum growth in the edge of woods environment, but also grew well in the full sun meadow environment. At harvest, the full sun meadow had the greatest number of seedlings present, while no seedlings survived in the pine woods site.     

Genotypic and phenotypic consequences of reintroduction history in the black-footed ferret (<Emphasis Type="Italic">Mustela nigripes</Emphasis>)

Population augmentation with translocated individuals has been shown to alleviate the effects of bottlenecks and drift. The first step to determine whether restoration for genetic considerations is warranted is to genetically monitor reintroduced populations and compare results to those from the source. To assess the need for genetic restoration, we evaluated genetic diversity and structure of reintroduced (n = 3) and captive populations of the endangered black-footed ferret (Mustela nigripes). We measured genotypic changes among populations using seven microsatellite markers and compared phenotypic changes with eight morphometric characters. Results indicated that for the population which rapidly grew post-reintroduction, genetic diversity was equivalent to the captive, source population. When growth languished, only the population that was augmented yearly maintained diversity. Without augmentation, allelic diversity declined precipitously and phenotypic changes were apparent. Ferrets from the genetically depaupertate population had smaller limbs and smaller overall body size than ferrets from the two populations with greater diversity. Population divergence (F _ST = 0.10 ± 0.01) was surprisingly high given the common source of populations. Thus, it appears that 5–10 years of isolation resulted in both genotypic divergence and phenotypic changes to populations. We recommend translocation of 30–40 captive individuals per annum to reintroduction sites which have not become established quickly. This approach will maximize the retention of genetic diversity, yet maintain the beneficial effects of local adaptation without being swamped by immigration.     

Protecting evolutionary significant units for the remnant populations of <Emphasis Type="Italic">Berchemiella wilsonii</Emphasis> var. <Emphasis Type="Italic">pubipetiolata</Emphasis> (Rhamnaceae)

Berchemiella wilsonii var. pubipetiolata (Rhamnaceae) is an endangered tree in eastern China. Habitat destruction has resulted in fragmentation of remnant populations and extinction of local populations. AFLP and cpDNA markers were used to determine the population structure of remnant populations of B. wilsonii var. pubipetiolata. Moderate nuclear genomic diversity was found within each of the four remnant populations (H _S = 0.141–0.172), while the cpDNA haplotype diversity in each population ranged from 0.356 to 0.681. Six haplotypes were identified by a combined cpRFLP and cpSSR analysis in a total of 89 individuals. AMOVA revealed significantly AFLP genetic differentiation within and between regions (Φ_SC = 0.196, Φ_CT = 0.396, respectively), and a high cpDNA haplotype differentiation between regions (Φ_CT = 0.849). The results suggest low gene flow between populations of B. wilsonii var. pubipetiolata. Strong genetic divergence between two regional populations as revealed by both AFLP and cpDNA markers provided convincing evidence that two distinct evolutionary lineages existed, and should be recognized as ‘evolutionary significant units’ (ESUs) for conservation concerns.     

<Emphasis Type="Italic">Agrobacterium</Emphasis><Emphasis Type="Italic">tumefaciens</Emphasis>-mediated transformation of callus cells of <Emphasis Type="Italic">Crataegus</Emphasis><Emphasis Type="Italic">aronia</Emphasis>

A genetic transformation system has been developed for callus cells of Crataegus aronia using Agrobacterium tumefaciens. Callus culture was established from internodal stem segments incubated on Murashige and Skoog (MS) medium supplemented with 5 mg l⁻¹ Indole-3-butyric acid (IBA) and 0.5 mg l⁻¹ 6-benzyladenine (BA). In order to optimize the callus culture system with respect to callus growth and coloration, different types and concentrations of plant growth regulators were tested. Results indicated that the best average fresh weight of red colored callus was obtained on MS medium supplemented with 2 mg l⁻¹ 2,4-dichlorophenoxyacetic acid (2,4-D) and 1.5 mg l⁻¹ kinetin (Kin) (callus maintenance medium). Callus cells were co-cultivated with Agrobacterium harboring the binary plasmid pCAMBIA1302 carrying the mgfp5 and hygromycin phosphotransferase (hptII) genes conferring green fluorescent protein (GFP) activity and hygromycin resistance, respectively. Putative transgenic calli were obtained 4 weeks after incubation of the co-cultivated explants onto maintenance medium supplemented with 50 mg l⁻¹ hygromycin. Molecular analysis confirmed the integration of the transgenes in transformed callus. To our knowledge, this is the first time to report an Agrobacterium-mediated transformation system in Crataegus aronia.     

Association mapping in multiple segregating populations of sugar beet (<Emphasis Type="Italic">Beta vulgaris</Emphasis> L.)

Association mapping in multiple segregating populations (AMMSP) combines high power to detect QTL in genome-wide approaches of linkage mapping with high mapping resolution of association mapping. The main objectives of this study were to (1) examine the applicability of AMMSP in a plant breeding context based on segregating populations of various size of sugar beet (Beta vulgaris L.), (2) compare different biometric approaches for AMMSP, and (3) detect markers with significant main effect across locations for nine traits in sugar beet. We used 768 F _n (n = 2, 3, 4) sugar beet genotypes which were randomly derived from 19 crosses among diploid elite sugar beet clones. For all nine traits, the genotypic and genotype × location interaction variances were highly significant (P < 0.01). Using a one-step AMMSP approach, the total number of significant (P < 0.05) marker-phenotype associations was 44. The identification of genome regions associated with the traits under consideration indicated that not only segregating populations derived from crosses of parental genotypes in a systematic manner could be used for AMMSP but also populations routinely derived in plant breeding programs from multiple, related crosses. Furthermore, our results suggest that data sets, whose size does not permit analysis by the one-step AMMSP approach, might be analyzed using the two-step approach based on adjusted entry means for each location without losing too much power for detection of marker-phenotype associations.     

Combined field efficacy of <Emphasis Type="Italic">Paranosema locustae</Emphasis> and <Emphasis Type="Italic">Metarhizium anisopliae</Emphasis> var. <Emphasis Type="Italic">acridum</Emphasis> for the control of sahelian grasshoppers

Field trials were conducted to evaluate the efficacy of wheat bran bait formulations of Paranosema locustae and Metarhizium anisopliae for controlling grasshoppers in southeast Niger. Treatments consisted of wheat bran baits mixed with M. anisopliae, P. locustae + M. anisopliae or with P. locustae spores and P. locustae + sugar. Oedaleus senegalensis, Pyrgomorpha cognata and Acrotylus blondeli were the predominant species at the time of application representing ca. 94% of the total population. Bran application was done when O. senegalensis (ca. 75% of the population) was at its early developmental stages, with first, second and third instars accounting for 64–85%. Grasshopper population reduction, P. locustae prevalence and level of infections in the predominant species were monitored. Manual application of P. locustae and M. anisopliae formulated in wheat bran has proven to induce consistent pathogen infection in grasshopper populations. Population density over the three weeks monitoring, typically decreased by 44.7 ± 6.9%, 52.8 ± 8.4%, 73.7 ± 5.5% and 89.1 ± 1.8% in P. locustae, P. locustae + sugar, M. anisopliae and P. locustae + M. anisopliae treated plots respectively. Paranosema locustae prevalence in surviving adult grasshoppers at 28 after application was 48.1 ± 2.3%, 28.9 ± 4.8% and 27.4 ± 3.7%, with infection level of 6.2 ± 0.8 × 10⁶, 2.3 ± 0.3 × 10⁴ and 2.1 ± 0.3 × 10³ spores mg⁻¹ host weight in O. senegalensis, A blondeli and P. cognate respectively. Other species that each accounted for <2% of the community, namely Aiolopus thalassinus, A. simulatrix, Acorypha glaucopsis, Acrotylus patruelis, Anacridium melanorhodon, Diabolocatantops axillaris, Kraussaria angulifera and Schistocerca gregaria were found to show sign of infection. The results from this study suggest that wheat bran application of M. anisopliae and P. locustae alone or in combination, targeting early instars grasshopper could be a valuable option in grasshopper control programs.