Experimental hybridization of sympatric temnopleurid sea urchins living in Yamaguchi, Japan

Three sympatric species of temnopleurid sea urchins, Temopleurus toreumaticus (Leske, 1778), T. hardwickii (Gray, 1855) and Mespilia globulus (Linnaeus, 1758), occupy a habitat located a short distance from the shore of the Seto Inland Sea, Yamaguchi Prefecture, Japan. Breeding seasons overlap considerably among these species. These species exhibit species-specific differences in embryonic and larval development such as a wrinkled zygote, wrinkled blastula, archenteron invagination, larval skeleton and juvenile morphology. In this study, we determined whether interbreeding among these species is possible. Investigations revealed that fertilization succeeded with all mating combination patterns and that all fertilized eggs developed to the gastrula stage. The blastula and gastrula of hybrids formed in a manner similar to the maternal whereas the developmental delay observed followed the pattern of the paternal species T. toreumaticus fertilized at a greater proportion than other pairs and metamorphosed. These results suggest that eggs of this species may have weaker fertilization block in general. At the early developmental stages, hybrid embryos from T. toreumaticus mothers express maternal, while some hybrids derived from sperm of T. toreumaticus and the eggs of other species ceased development at the 4-armed larval stage. The hybrids of T. hardwickii and M. globulus ceased development at the gastrula stage, suggesting that these species have a greater degree of genetically isolation distance. In hybrids of T. toreumaticus and strongylocentrotid Hemicentrotus pulcherrimus (A. Agassiz, 1864), larval skeletons expressed features from both species. These results suggest that traits of hybrids are derived not only from one or both original species, but that a mosaic effect can be obtained depending on the traits. These results indicate that temnopleurids have the weaker fertilization block mechanisms. Isozyme analyses showed that hybrid prisms of T. toreumaticus eggs and M. globulus sperm possess enzymatic patterns of malate dehydrogenase derived from each parent, whereas the enzymatic pattern of glucose-6-phosphate dehydrogenase is derived from eggs, suggesting that malate dehydrogenase activity may be useful in detecting naturally occurring adult hybrids among these species in the Yamaguchi coastal area.

Genetic Variability of Five Provenances of Eboni

A research was conducted to determine genetic variability and structure of ebony either within provenances or within trees in the same provenance using isozyme analyses. Results of this study are expected to show genetic variability of ebony with different provenances. For the purpose of the study, five provenances of ebony (Maros,Barru, Sidrap, Malili, and Mamuju) were prepared. The isozyme analysis using electrophoresis was applied to determine the genetic variability. The obtained data were statistically analyzed using multivariate and dendrogram analyses with Numerical Taxonomy System (NTSYS) Program applying unwighted pairgroup method and arrithmetic average (UPGMA) approach. Results showed that the variability of genetic provenances of ebony were less than any other tree species. Among the existing provenances, Barru dan Mamuju showed higher genetic variability compared to other provenances. Ebony provenance was generally found to homozygously increase or to performinbreeding. The genetic variability of ebony was mostly derived from the variability in population (95.4%). Grouping individual trees based on their provenances indicated that Malili provenance showed closed relationship to Maros provenance, whilst Mamuju provenance showed closed relationship to Barru and Sidrap provenances.

Genetic structures of common ash (Fraxinus excelsior) populations in Germany at sites differing in water regimes

The genetic structure of the alcohol dehydrogenase (ADH) enzyme complex was studied by means of isozyme analysis among several common ash ( Fraxinus excelsior L.) provenances. We analysed if specific alloforms of locus ADH-B are selected under flooding stress caused by oxygen deprivation, since ADH is a fundamental enzyme of the plant metabolism under anoxia. This selection, if given, could therefore result in different ash ecotypes. Furthermore, genetic structures in the same provenances resulting from the analysis of four nuclear microsatellite markers are also discussed and compared with those resulting from the isozyme analyses to differentiate between adaptation and demographical processes. We found the highest value of genetic diversity at one of the two examined floodplains but did not find significant correlations between genotypes structures and flooding. The observed allele distributions can be mainly attributed to high human pressure and important seed transport events. These are regarded as the main forces shaping the actual genotype distributions rather than selection processes acting on locus ADH-B.

Genetic variability within Serbian populations of the rare and endangered pottioid moss Hilpertia velenovskyi (Schiffn.) Zander inferred by isozyme analyses

Genetic variability within Serbian populations of the pottioid moss Hilpertia velenovskyi (Schiffn.) Zander was studied. Eight populations of this rare and endangered moss species were chosen for peroxidase isozyme analyses. From the data obtained, it can be inferred that four haplotypes are present among H. velenovskyi populations in Serbia, the Banat population being distinctive from all others.

Inheritance of glyphosate resistance in goosegrass (Eleusine indica)

The inheritance of glyphosate-resistant goosegrass was studied by making reciprocal crosses between resistant (R) and susceptible (S) biotypes. Eighty-four F1hybrids were confirmed using isozyme analyses. Reciprocal F1hybrids displayed uniform levels of resistance intermediate (I) to that of the parental types, with no indication of maternal inheritance. The F1hybrids were selfed to produce F2populations. F3populations were produced by selfing resistant and intermediate F2phenotypes. A segregation ratio of 1:2:1 (S:I:R) was observed in the F2and subsequently in the F3generations derived from selfing intermediate F2phenotypes. Individuals in F3families derived from selfing resistant F2phenotypes were resistant. Results from the present study show that glyphosate resistance in goosegrass is inherited as a single, nuclear, and incompletely dominant gene.

Incidence of Infection and Decay Caused by Heterobasidion annosum in Managed Noble Fir on the Warm Springs Indian Reservation, Oregon

On the Warm Springs Indian Reservation in north-central Oregon, a 70- to 80-yr-old noble fir stand that was thinned 26 yr prior to sampling exhibited 72% incidence of H. annosum infection for wounded trees and 83% for unwounded trees. Decay volume averaged 6% in wounded trees and 1% in unwounded trees. In a similar stand that was thinned 7 yr prior to sampling, incidence of infection was 94% for wounded trees and 80% for unwounded trees. Decay volume averaged 3% in wounded trees and 0% in unwounded trees. Trunk wounds and stumps created from thinning both appeared to be effective infection courts. We developed a regression model that demonstrates increasing decay volume with increasing wound age and thinning stump diameter. Only the S-type intersterility group H. annosum was detected in our isolates using isozyme analyses. Vegetative compatibility (VC) tests in one stand revealed an average of 2.7 VC groups/tree. Multiple VC groups in individual trees suggest that wound infection by H. annosum spores is significant in managed noble fir. Our results support the common recommendations to treat stumps with boron-containing products and avoid trunk wounding during harvest to minimize subsequent spore infections by H. annosum. West. J. Appl. For. 16(3):106–113

A Stenospermocarpic, Seedless Vitis vinifera × Vitis rotundifolia Hybrid Developed by Embryo Rescue

Hybridizations between seedless Vitis vinifera L. genotypes and V. rotundifolia (Michx.) were made specifically to introgress the seedless trait into the disease-resistant background of V. rotundifolia. The seedless, gynoecious P79-101 was hybridized with three V. rotundifolia parents, producing a total of 102 ovules. From these ovules, 44 embryos developed, producing 20 plants. Isozyme analyses and morphological traits confirmed that 19 of the plants were hybrids. Sixteen were planted in an experimental vineyard at California State Univ. Fresno. One seedling, C41-5, produced seedless fruit that appeared to be stenospermocarpic based on fruit and aborted seed size. Fruit weight was slightly less than that of `Thompson Seedless' (stenospermocarpic) and at least twice that of parthenocarpic fruit of `Black Corinth' and C41-7, a seeded hybrid with many parthenocarpic fruit. Aborted seeds of C41-5 were larger than, but not significantly different from, those of `Thompson Seedless', while parthenocarpic fruit from `Black Corinth' and C41-7 had aborted seeds that were smaller than those of C41-5. Seed weight of C41-7 averaged almost 10 times that of aborted C41-5 seeds. This is the first report of a stenospermocarpic, seedless hybrid of V. vinifera × V. rotundifolia.

Genetic relationships between Australian fireweed and South African and Madagascan populations of Senecio madagascariensis Poir. and closely related Senecio species

An isozyme and morphological study of Senecio madagascariensis Poir. and closely related species in Australia, South Africa and Madagascar was used to investigate the most likely region of origin for Australian plants known as fireweed. Collections of seed and voucher specimens were made in New South Wales, KwaZulu-Natal, East and West Cape Provinces and southern Madagascar and specimens classified according to recognised taxa or descriptive variants. Plants were characterised by using isozyme analyses and morphological observations of both voucher specimens and achenes. Australian fireweed populations were found to be most closely related to populations of S. madagascariensis from KwaZulu-Natal in South Africa, and to be more distantly related to populations from East and West Cape Provinces in South Africa and from Madagascar. The implications of these findings are discussed in relation to efforts to locate host-specific biological control agents for fireweed.