bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interspecific hybrids between three eggplant (Solanum melongena L.) cultivars and two wild species (Solanum torvum Sw. and Solanum sisymbriifolium Lam.)
Authors: Bletsos F. A. , Roupakias D. G. , Tsaktsira M. L. , Scaltsoyjannes A. B. , Thanassoulopoulos C. C. 
Published: April 2006

AbstractThree Greek eggplant cultivars, ‘Langada’, ‘Tsakoniki’ and ‘Emi’ (2n= 24), were crossed with two wild species (Solanum torvum Sw., 2n= 24 and Solanum sisymbriifolium Lam., 2n= 24). Ovules isolated 15‐27 days after pollination were cultured in a modified MS medium at 24°C and a 16h photoperiod. Fifty days later, the ovules were dissected and the interspecific embryos were cultured in the same medium. Interspecific hybrids were achieved only from crosses between the eggplant cultivars and S. torvum. The hybridity of the putative interspecific F1 hybrid (Solanum melongena×S. torvum) was confirmed by using morphological and biochemical (isozyme isocitrate dehydrogenase A, phosphoglucomutase A, phosphoglucose isomerase B, 6‐phosphogluconate dehydrogenase A, 6‐phosphogluconate dehydrogenase B) markers. The F1 plants (‘Langada’×S. torvum) were selfpollinated and backcrossed to both parents. Fruits, however, were produced only when the F1 hybrid was backcrossed as female with the eggplant cultivar ‘Langada’.
Response of tolerant breeding lines of tomato, Lycopersicon esculentum, originating from three different sources (L. peruvianum, L. pimpinellifolium and L. chilense) to early controlled inoculation by tomato yellow leaf curl virus (TYLCV)
Authors: Vidavsky F. , Leviatov S. , Milo J. , Rabinowitch H. D. , Kedar N. , Czosnek H. 
Published: April 2006

AbstractSelection of tomato plants supposedly tolerant to tomato yellow leaf curl virus (TYLCV), based solely on the absence of symptoms in an infested field can be misleading. An inoculation routine was therefore established to avoid escapes and to overcome difficulties associated with the age of the plant at the time of infection. The inoculation routine was applied to a selection of resistant/tolerant individuals generated through a diallel F1 cross and to F2 segregating populations originating from three wild tomato species described as tolerant to TYLCV: Lycopersicon peruvianum EC 104395, Lycopersicon pimpinellifolium Hirsute and Lycopersicon chilense LA 1969. Clear differences were observed between susceptible symptomatic and tolerant symptomless tomato genotypes, indicating that the uncertainty resulting from escapes, from different levels of inoculum, and from the time of inoculation, can be eliminated. The genes involved in tolerance provided different levels of protection; combinations of various tolerant sources and levels in a single genotype gave a higher level of tolerance. Differences in level of protection were found between genes from the same source and between sources; none of the sources tested had complete dominance. The results obtained with the F2 segregating population showed that tolerance from L. pimpinellifolium is controlled by one major gene, that from L. chilense by two genes, and that from L. peruvianum by three genes with no dominant effect. The combination of sources for resistance can thus have positive or negative synergistic effects, or no effect. We suggest that a maximal level of tolerance can be obtained by the additive effect of the partly dominant genes from L. pimpinellifolium and L. chilense.
Genetic analysis of low‐temperature tolerance during germination in tomato, Lycopersicon esculentum Mill.
Authors: Foolad M. R. , Lin G. Y. 
Published: April 2006

AbstractThe genetic basis of low‐temperature tolerance during germination of tomato seed was investigated using two approaches. First, a cold‐tolerant (PI 120256) and a cold‐sensitive tomato cultivar (UCT5) and their reciprocal F2, F3 and BC1 progeny (total of 10 generations) were evaluated for germination at a low (11 ± 0.5°C) and a high (control) temperature 20 ±0.5° C) Weighted least‐square regression analysis indicated that in the low‐temperature treatment most of the variation resulted from additive genetic effects, and dominance and epistatic interactions were nonsignificant. Partitioning of the total genetic variance into those attributable to the effects of embryo, endosperm, testa and the cytoplasm indicated that additive effects of endosperm and embryo could individually account for 80% and 77% of the total variance, respectively. In the control treatment, greater than 60% of the variation could be explained by individual additive effects of endosperm or embryo and ≅ 27% of the variation could be explained by embryo dominance effects. Across generations, there was a positive correlation (r = 0.78, P < 0.01) between germination in the control and low‐temperature treatments and there were no significant genotype × temperature interactions. The results indicate the presence of similar or identical genes with predominantly additive effects on germination under both low and high temperatures. In the second approach, the effectiveness of directional phenotypic selection to improve tomato cold tolerance during germination was evaluated by selecting (in an F2 population of the same cross) the fastest germinating seeds under low temperature and comparing the germination of the selected F3 progeny with germination of an unselected F3 population. The results indicated that selection was highly effective and significantly improved germination performance of the progeny; a realized heritability of 0.74 was obtained for low‐temperature tolerance during germination. It is concluded that in these tomato lines germination under low temperature is genetically controlled, with additivity being the major genetic component, and thus the trait can be improved by phenotypic selection.
Development of synthetic maize populations for resistance to Striga hermonthica
Authors: Kim S. K. , Fajemisin J. M. , Thé C. , Adepoju A. , Kling J. , Badu‐Apraku B. , Versteeg M. , Carsky R. , Lagoke S. T. O. 
Published: April 2006

ABSTRACTThe parasitic witchweed, Striga hermonthica (Del.) Benth, is the greatest biological constraint for cereal crop production by resource‐poor farmers in sub‐Saharan Africa. Maize, Zea mays L., is a widely grown cereal crop in this region (22 × 106 ha). Striga‐resistant maize populations were produced and tested as half‐sib families in West and Central Africa. Three populations with white (W), yellow (Y), or mixed (Y/W) grain colour were formed by: (1) intercrossing Striga resistant maize inbred lines followed by two generations of random mating; (2) testing far under artificially induced S. hermonthica infestations in Nigeria, Cameroon, and Ivory Coast and selection of resistant families; (3) two generations of random mating; and (4) two years of testing for resistance. Striga‐resistant synthetic W, Y and Y/W populations were produced by compositing resistant half‐sib families. Outstanding performance in grain yields and host plant resistance was observed. Maize damage ratings and number of harvested ears were highly correlated with grain yield. High variation was observed for Striga emergence counts. The populations have combined resistance to Striga, maize streak virus (MSV), and other major biotic constraints for maize cultivation in Africa, thus providing the opportunity for improved sustainable maize production under stress environments. Breeder's seed of these synthetic varieties are being multiplied for distribution to national programmes.
Production of doubled haploids in triticale (×Triticosecale Wittm.) by means of crosses with maize (Zea mays L.) using picloram and dicamba
Authors: Wȩdzony M. , Marcińska I. , Ponitka A. , ŚLusarkiewicz‐Jarzina A. , Woźna J. 
Published: April 2006

AbstractThe aim of the present study of triticale × maize crosses was to find an appropriate growth regulator treatment to improve the yield of triticale haploids and the subsequent production of doubled haploids. The growth effect in unpollinated ovaries of triticale was examined after treatment with 1000 mg/1 indole‐3‐acetic acid (IAA) or 100 mg/1 solutions of the following auxin analogues: 2,4‐dichlorophenoxyacetic acid (2,4‐D), 3,6‐dichloro‐o‐anisic acid (dicamba), 4‐chloro‐o‐tolyloxyacetic acid (MCPA), phenylacetic acid (PAA), 4‐amino‐3,5,6‐trichloropicolinic acid (picloram) and 2,4,5‐trichlorophenoxyacetic acid (2,4,5‐ T), respectively. Dicamba stimulated growth of the ovaries significantly more than picloram and both stimulated more growth than the other growth regulators tested. Neither dicamba nor picloram induced embryo development in unpollinated pistils. Dicamba and picloram solutions, at concentrations of 25, 50, 75 and 100 mg/1, were subsequently applied to pistils of triticale pollinated with maize. On average, between 17.1 and 21.5 embryos/100 fiorets were excised after treatment with 75 or 100 mg/1 solutions of picloram or dicamba but the concentrations of 20 and 50 mg were less effective. The frequencies of excised embryos did not differ between genotypes. Seventy‐six green haploids were obtained from 100 embryos rescued in vitro on the 190–2 and modified B5 media, the first medium being superior. The plants were subjected to colchicine treatment at the 3–4 tiller stage. Out of 68 plants brought to maturity, 25 exhibited fertile sectors. In comparison with previous studies, picloram and dicamba significantly improved the efficiency of the triticale × maize crossing. The low dependence on the mother germplasm makes triticale × maize crossing an efficient alternative to the androgenetic methods of doubled haploid production in triticale.
Classification of Brazilian wheat cultivars for aluminium toxicity in acid soils
Authors: De Sousa C. N. A. 
Published: April 2006

AbstractAluminium (Al) toxicity is an important limiting factor for wheat Triticum aestivum L. adaptation to acid soils in different regions of Brazil. The purpose of this research was to classify the reaction of recommended wheat cultivars in Brazil in relation to Al toxicity. Seventy‐five cultivars were tested from 3 to 15 years under field conditions from 1980 to 1995 in Passo Fundo, Brazil. Soils with pH between 4.2 and 4.9 contained from 2.50 to 4.27 cmol Al/1. The resistance to aluminium in acid soil was evaluated visually before heading time in some years and at maturity in all years in three replications, using a score ranging from 0.5 (highly resistant) to 5 (highly susceptible). Using the over‐years mean index, 19 cultivars were classified as resistant, 33 as moderately resistant, 17 as moderately susceptible, and six as susceptible. The cultivars ‘BH 1146’, ‘Embrapa 15’, ‘Embrapa 24’, ‘Embrapa 49’, ‘IAC 5‐Maringá’, ‘IAC 18‐Xavantes’, ‘IAC 27‐Pantaneiro’, ‘IAPAR 46’, ‘IAPAR 53’, ‘RS 8‐Westphalen’, Trigo BR 15’, ‘Trigo BR 20‐Guató’, ‘Trigo BR 25’, ‘Trigo BR 35’, and ‘Trigo BR 41‐Ofaié’ were the most Al resistant of the 75 tested. It is highly probable that all Brazihan Altolerant cultivars have a major gene known to be on the long arm of chromosome 4D. Aluminium tolerance was traced by pedigree analysis to a small number of landraces introduced and grown in Brazil in the early twentieth century. Breeding for resistance to Al is required because soil amehoration by liming is effective only in the upper root zone and susceptible or moderately susceptible cultivars do not develop extensive root systems and suffer under drought or heat stress.
Genetic variability in foxtail millet, Setaria italica (L.) P. Beauv. ‐ RFLP using a heterologous rDNA probe
Authors: Schontz D. , Rether B. 
Published: April 2006

AbstractRibosomal DNA was surveyed in a world collection (43 lines) of Setaria italica for variation in repeat unit length and restriction enzyme site variability using a non‐radioactive wheat rDNA probe. Only two lengths of repeat units of about 7.9 or 7.6 kb were observed. The fact that these two repeat unit lengths were not randomly dispersed throughout the world collection suggests the existence of three genetic groups. The central European lines and most western European accessions have only the 7.6 kb repeat unit and most Asiatic lines have a 7.9 kb repeat unit. Lines originating from the north or the south of Asia showed different numbers of Bam HI fragments. The fact that the difference between the Asiatic and European pool is not continuous (7.9 or 7.6 kb) excludes the hypothesis of domestication being based on the spread of an initial population over Eurasia.
Genetic variation within eight populations of perennial forage grasses
Authors: Casler M. D. 
Published: April 2006

AbstractInformation on both mean performance and genetic variation is important in determining the value of germplasm for breeding via recurrent selection. The objectives of this experiment were to evaluate different methods of controlling spatial variation for forage yield, and to estimate genetic variances and heritability in eight perennial forage grass populations. Polycross families of two populations of smooth bromegrass (Bromus inermis Leyss.), two populations of hybrid wheatgrass (Elytrigia×muctonata (Opiz ex. Bercht.) Prokud.), and four populations of orchardgrass (Dactylis glomerata L.) were field tested for 2 years. Spatial variation was present in all three progeny tests, but was well accounted for by either the incomplete block design or a nearest neighbour analysis (NNA) of yield potentials. Low rank correlations between adjusted family means for the incomplete block design vs. the NNA created the unanswered question of which would provide a more appropriate estimate of family mean performance. Genetic variation was detected in six out of eight populations for forage yield, four out of six populations for ground cover, all four orchardgrass populations for maturity and one of four orchardgrass populations for leafspot reaction (caused by Drechslera spp.). Excessive year‐family interactions prevented detection of genetic variation for leafspot reaction in the other populations. Heritability estimates ranged from 0.30 to 0.42 for forage yield. In all three species, there was a trend toward a negative relationship between population mean and genetic variance, suggesting that less elite populations may need to contribute other traits to be useful in the short term.
In vitro rescue of zygotic embryos of sour orange, Citrus aurantium L., and their detection based on RFLP analysis
Authors: Carimi F. , De Pasquale F. , Puglia A. M. 
Published: April 2006

AbstractEmbryo development in vivo has been studied in four Citrus aurantium L. polyembryonic genotypes. Seeds were collected 65, 85, 105, 125 and 220 days after pollination (DAP). None of the immature seeds harvested 65 and 85 DAP contained visible embryos. A single embryo at a more advanced developmental stage was observed in the central position at the micropylar apex of the embryo sac in about 74% of seeds harvested at 105 DAP, while at 125 and 220 DAP the majority of seeds had two or more embryos at the same developmental stage crowded together. Restriction fragment length polymorphism (RFLP) analysis of lowand high‐copy‐number nuclear DNA was used to distinguish zygotic from nucellar seedlings. Analysis of plantlets derived from in vitro culture of the bigger embryos, located in the central position at the micropylar apex of the embryo sac of seeds harvested at 105 DAP, established that the frequencies of zygotic embryos ranged from 82 to 88%. Media for immature embryo germination in vitro were based on the nutrients and vitamins of Murashige and Skoog (MS) and Murashige and Tucker (MT) media supplemented with various concentrations of sucrose and growth regulators. A total of 76% of globular stage embryos (<0.3mm) germinated on MT medium containing 150 mM sucrose and 14.4 μM gibberellic acid. Heart stage embryos (0.3‐0.8 mm) germinated at 95% on MT medium supplemented with 150 mM sucrose and 2.9 μM gibberellic acid. The addition of 500 mg/l malt extract to MS medium increased the germination of early cotyledon stage (0.8‐2.0mm) embryos to 98%. The optimum sucrose concentration for embryo rescue was 150 mM for the three embryo developmental stages. The ability to form plants in vitro strongly increased with increasing embryo developmental stage.
Identification of five physiological races of blackspot, Diplocarpon rosae, Wolf on roses
Authors: Debener T. , Drewes‐Alvarez R. , Rockstroh K. 
Published: April 2006

AbstractDifferentiation into physiological races of Diplocarpon rosae, which causes blackspot on wild and cultivated roses, was investigated with single conidial isolates of the pathogen. Infection experiments with a simple excised leaf assay demonstrated differential interactions between single isolates and a set of 10 test rose genotypes. Differential reactions could be observed among rose varieties as well as between and within a wild rose species. Accordingly, five different physiological races can be identified among the 15 isolates tested. A breeding line and one genotype of the wild species Rosa wichuraiana were found to be resistant against all isolates tested. These data will be employed in further investigations on the genetics of blackspot resistance in roses and for resistance breeding programmes.
Second cycle gynogenesis in onion, Allium cepa L., and genetic analysis of the plants
Authors: Javornik B. , Bohanec B. , Campion B. 
Published: April 2006

AbstractHaploid induction in onion via gynogenesis provides inbred lines that can be used in production of hybrid cultivars. Despite several successful reports, the gynogenic induction rate is still relatively low, ranging mainly from 0.5 to six embryos per 100 cultured flowers. In the present study, gynogenesis was induced in selfed progeny of three genetically homozygous and stable fertile doubled haploid lines previously obtained through in vitro gynogenesis. The aims were to acquire information on whether the gynogenic responsiveness of a particular heterozygous cultivar is correlated with higher or lower gynogenic capacity in the second cycle of gynogenesis, to evaluate the non‐genetic component of the variability, and to monitor by random amplified polymorphic DNA (RAPD) analysis the onset of eventual gametoclonal variation induced during the gynogenic processes. The results from the gynogenic induction of 9708 flowers showed significant differences among three lines, one of them being extremely responsive, showing a mean yield of 118.3 haploid embryos per 100 cultured flowers (118.3%). The high embryo yield of this line was determined by the line's particular genotype. However, the induction rate of gynogenic embryos obtained within 24 genetically uniform donor plants of this responsive line varied from 67 to 196% and this variation can be attributed to uncontrolled environmental conditions. A total of 157 plants sampled from two lines and obtained through a first (RI) and a second (SCG) cycle of gynogenesis, was analysed by RAPDs. The single band profiles were compared either between or within the RI and SCG plants of each line. A total number of 4600 RAPD fragments were scored and no variation was found in the highly responsive line, while in the less responsive one, minor changes were detected for the presence/absence of two RAPD bands. These results indicate high genetic stability of onion homozygous lines passed through two cycles of gynogenesis.
Reproductive behaviour and broomrape resistance in interspecific hybrids of sunflower
Authors: Sukno S. , Jan C. C. , Melero‐Vara J. M. , Fernandez‐Martinez J. M. 
Published: April 2006

AbstractInterspecific hybrids and backcross generations between the wild perennial species Helianthus resinosus, Helianthus paucifiorus, Helianthus laevigatus, Helianthus nuttallii ssp. nuttallii T. & G. and Helianthus giganteus, resistant to broomrape (Orobanche cernua) and susceptible inbred lines were obtained to study crossability to cultivated sunflower and the transmission and expression of resistance to this parasitic weed. Conventional crosses with all the species tested were successful except for the crosses with diploid H. giganteus, for which embryo rescue techniques were needed to overcome hybrid incompatibility. Pollen viability and seed set were highest for F1 hybrids with hexaploid species and lowest for those with the diploid H. giganteus. We evaluated F1, BC1F1, some BC2F1 plants and the wild and cultivated parents. The wild species and interspecific hybrids were resistant to broomrape infection except for H. nuttallii, which showed segregation, indicating that the resistance is dominant. The crossability and resistance of F1, and back‐cross generations of species with different ploidy levels indicate that the transfer of broomrape resistance to cultivated sunflower is feasible.
Random amplified polymorphic DNA variation among German and Dutch asparagus cultivars
Authors: Jaag T. , Langsdorf A. , Snowdon R. J. , Köhler W. , Hartmann H. D. 
Published: April 2006

AbstractDNA polymorphism among nine cultivars of Asparagus officinalis L. was measured using random amplified polymorphic DNA (RAPD). Of 69 reproducible amplification products from 12 arbitrary decamer primers, 49 RAPD markers were polymorphic and could be used to distinguish six German and three Dutch asparagus cultivars. Even with very small sample sizes, genetic similarity measurements based on the RAPD data allowed accurate grouping of the nine cultivars into distinct clusters, with the exception of two individuals which clustered to closely related varieties. Two German cultivars showed high genetic similarity and were distinct from the remaining German varieties. The German and Dutch cultivars were clearly separated by a relatively large genetic distance.
Inheritance of Russian wheat aphid resistance in PI 140207 spring wheat
Authors: McIntosh R. A. , Porter D. R. , Baker C. A. , Webster J. A. 
Published: April 2006

AbstractThe Russian wheat aphid (RWA), Diuraphis noxia (Mordvilko), has become a serious, perennial pest of wheat (Triticum aestivum L.) in many areas of the world. This study was initiated to determine the inheritance of RWA resistance in PI 140207 (a RWA‐resistant spring wheat) and to determine its allelic relationship with a previously reported RWA resistance gene. Crosses were made between PI 140207 and ‘Pavon’ (a RWA‐susceptible spring wheat). Genetic analysis was performed on the parents, F1, F2, backcross (BC) population and F2‐derived F3 families. Analyses of segregation patterns of plants in the F1, F2, and BC populations, and F2‐derived F3 families indicated single dominant gene control of RWA resistance in PI 140207. Results of the allelism test indicated that the resistance gene in PI 140207, while conferring distinctly different seedling reactions to RWA feeding, is the same as Dn 1, the resistance gene in PI 137739.