bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phenylacetic acid stimulation of direct shoot formation in anther and somatic tissue cultures of rice (Oryza saliva L.)
Authors: Zhuo L. S. , Si H. M. , Cheng S. H. , Sun Z. X. 
Published: April 2006

AbstractThe effect of phenylacetic acid (PAA) on rice (Oryza saliva L.) anther culture was investigated with six genotypes, using 2,4‐D as control. In the two‐step culture protocol, replacing 2, 4‐D with PAA in the induction medium did not influence callus induction but significantly improved the shoot differentiation from callus, particularly in the indica cultivar Teqing. The anther‐derived calli of all genotypes regenerated shoots directly on the callus induction medium containing PAA. Most of the directly‐regenerated plantlets had well‐developed root systems and were therefore readily transplanted into soil. The improved shoot differentiation potential and the frequency of direct regeneration depended on genotype, basal medium and PAA concentration. The one‐step green shoot regeneration frequencies obtained were 1.98% with the indica cultivar ‘129’, 1.5% with the indica × japonica hybrid ‘Teqing/02428’ (F1), and 1.98% with the indica × indica hybrid ‘Waiyin 2/C.B.’ (F1). The PAA‐based one‐step method was most effective on the anther culture of indica genotypes. Three DH populations have been constructed from hybrids (F1) via one‐step culture. PAA also enhanced the one‐step plantlet formation in rice somatic tissue culture.
N‐banded karyotype of Aegilops ovata and chromosomal constitution of its amphiploid with Triticum aestivum
Authors: Landgeva S. , Ganeva G. 
Published: April 2006

AbstractThe N‐banded karyotype of an Aegilops ovata (2n = 4x = 28) accession was produced, and the chromosomal constitution of its partial amphiploid with bread wheat Triticum aestivum‘Chinese Spring’ was established. All A. ovata chromosomes showed specific N‐banding patterns and can easily be distinguished from each other. As a result of irregular meiotic behaviour of the chromosomes in the amphiploid, some structural rearrangements have probably occurred in most of the A. ovata chromosomes. The wheat chromosomes remained unmodified in their morphology and the N‐banding patterns.
Genetic diversity of Cannabis sativa germplasm based on RAPD markers
Authors: Faeti V. , Mandolino G. , Ranalli P. 
Published: April 2006

AbstractRandom amplified polymorphic DN A (RAPD) markers were generated from 13 cultivars and accessions of Cannabis sativa L. Approximately 200 fragments generated by 10 primers of arbitrary sequence were used to assess the level of DNA variation. Statistical analysis was performed using the Dice coefficient of similarity and principal coordinate analysis. The grouping of the accessions according to the cluster analysis was in good agreement with their origin and lines with common ancestors were grouped together. Principal coordinates 1 and 2 revealed a clear separation of Italian and Hungarian germplasm and a third group, including a mixture of genotypes coming from different places; the third coordinate separated the Korean group which is probably the most divergent germplasm. Variability within the two cultivars ‘Carmagnola’ and ‘Fibranova1’ was also shown, suggesting good possibilities for long–term selection work. RAPD markers provide a powerful tool for the investigation of genetic variation in cultivars/accessions of hemp.
Inheritance of threshability in synthetic hexaploid (Triticum turgidum×T. tauschii) by T. aestivum crosses
Authors: Villareal R. L. , Mujeeb‐Kazi A. , Rajaram S. 
Published: April 2006

Abstract Triticum tauschii provides breeders with a valuable source of resistance and tolerance genes. Elucidation of the inheritance of traits in this species that hinder its use in breeding programmes is therefore of interest to wheat breeders. Inheritance of threshability was investigated in the crosses of four non‐free‐threshing (NFT) synthetic hexaploids (Triticum turgidum×T. tauschii) and two free‐threshing (FT) T. aestivum cultivars during four crop seasons over 3 years at E1 Batan and Ciudad Obregon, Mexico. The parents, their F1 Hybrids and individual F2 plant‐derived F3 progenies of the crosses revealed that ‘Altar 84’/T. tauschii (219), ‘Chen’/T. tauschii (205), ‘Chen’/T. tauschii (224), and ‘Duergand’/T. tauschii (214) have independently segregating loci with two dominant alleles controlling threshability. Intercrosses among the synthetics, except ‘Altar 84’/T. tauschii (219), showed the genes to be allelic to each other. The cross between the FT cultivars showed no segregation in the F3 generation, indicating common recessive genes. Based on these findings, population sizes of the synthetic‐derived breeding materials should be increased to improve the chances of selecting FT desirable plants in the programme.
Resistance specificities to viruses in potato: Standardization of nomenclature
Authors: Valkonen J.P.T. , Jones R.A.C. , Slack S.A. , Watanabe K. N. 
Published: April 2006

AbstractPotato viruses are prevalent worldwide and cause substantial economical losses in the potato crop (Solanum tuberosum L.). Therefore, various types of resistance to potato viruses identified in cultivated and wild potato species are used in potato breeding programs and are briefly reviewed in this paper. However, the current nomenclature of virus resistance specificities is confusing because it was adopted at an earlier time when several virus strain groups were believed to represent individual virus species and because it does not distinguish between strain‐specific and comprehensive resistance specificities. A consistent nomenclature is desirable to distinguish both currently known virus resistances and any novel virus resistances detected in the future. A descriptive and systematic nomenclature for resistance specificities is proposed which denotes (1) type of resistance (2) identity of virus (3) the virus strain group(s) against which the resistance is effective (4) the virus strain group(s) against which the resistance is not effective, and (5) the potato species in which the resistance is described.
Variation and covariation of agronomic traits and quality in triticale at low nitrogen input
Authors: Oettler G. 
Published: April 2006

AbstractThe use of high nitrogen (N) inputs is becoming restricted in many countries due to environmental and economic considerations and reliable information is needed about parameters pertinent for breeding N‐use efficient triticales (x Triticosecale Wittmack). This study reports estimates of variances, heritabilities, correlations, and regression for 36 triticales, grown at three locations for 2 years with two N regimes (zero and normal N supply). Eleven traits were assessed. A 45% mean reduction in grain yield by low N input was mainly the result of a 25% lower number of tiller‐bearing spikes per m2 and 17% fewer kernels per spike, whereas 1000‐kernel weight was little affected. Genotype‐nitrogen interaction was of importance only in some environments and for certain traits. Heritability estimates at both N levels were similar and moderate to high. Correlations between N levels were high for nearly all traits. Regression analysis for grain yield revealed only few N‐efficient triticales with lower than unity slope together with a high grain yield. Based on the genetic parameters, it is concluded that a special low input breeding programme does not appear to be necessary in triticale. The breeder can select at either of the N levels with similar response. But he should include tests in low productivity environments at some early stages in the breeding process to avoid loss of genetic variation for N‐use efficiency.
Genetic control of some polymeric glutenin fractions in hexaploid wheat (Triticum aestivum)
Authors: Haddad L. El , Sarrafi A. , Fabre J. L. , Aussenac T. 
Published: April 2006

AbstractReciprocal crosses were made between seven different hexaploid wheat genotypes. Hybrid kernels and their parents were used to determine the amount of polymeric glutenin fractions by size‐exclusion high‐performance liquid chromotography (SE‐HPLC) analysis. Quantitative aspects of the genetic control for various glutenin fractions were investigated through diallel cross analysis. The association between the potential effect on hexaploid wheat quality of various allelic types and the quantitative expression of the polymeric glutenin fractions was confirmed. Significant average heterosis effects were demonstrated for insoluble glutenin (pFi), total soluble and insoluble glutenin (pF1 + pF2 + pFi) and the ratio of soluble to insoluble glutenin, (pF1 + pF2)/pFi. Some genotypes showed significant positive or negative combining abilities and general reciprocal effects for the glutenin fractions studied. For gluten quality, ‘Qualital’ was the best combiner for determining an optimal glutenin composition (high values for pFi and pF1 + pF2 + pFi and low values for pF1/pF2 and (pF1 + pF2)/pFi, respectively). These results should be of great interest in breeding programmes aimed at improving hexaploid wheat quality.
Genetic basis of physiological traits related to salt tolerance in tomato, Lycopersicon esculentum Mill.
Authors: Foolad M. R. 
Published: April 2006

AbstractGenetic relationships between salt tolerance and expression of various physiological traits during vegetative growth in tomato, Lycopersicon esculentum Mill., were investigated. Parental, F1, F2 and backcross progeny of a cross between a salt tolerant (PI174263) and a salt sensitive tomato cultivar (‘UCT5’) were evaluated in saline solutions with electrical conductivity of 0.5 (non‐stress) and 20 dS/m (salt stress). Absolute growth, relative growth, tissue ion content, leaf solute potential and the rate of ethylene evolution were measured. Growth of both parents was reduced under salt stress; however, the reduction was significantly less in PI174263 than ‘UCT5’, suggesting greater salt tolerance of the former. Under salt stress, leaves of PI174263 accumulated significantly less Na+ and Cl− and more Ca2+ than leaves of ‘UCT5’. Across parental and progeny generations, growth under salt stress was positively correlated with leaf Ca2+ content and negatively correlated with leaf Na+ content. In contrast, no correlation was observed between growth and either leaf solute potential or the rate of ethylene evolution under salt stress. Generation means analysis indicated that under salt stress both absolute and relative growth and the Na+ and Ca2+ accumulations in the leaf were genetically controlled with additivity being the major genetic component. The results indicated that the inherent genetic capabilities of PI174263 to maintain high tissue Ca2+ levels and to exclude Na+ from the shoot were essential features underlying its adaptation to salt stress and that these features were highly heritable. Thus, tissue ion concentration may be a useful selection criterion when breeding for improved salt tolerance of tomato using progeny derived from PI174263.
Inheritance of sesquiterpene lactone types within the Achillea millefolium complex (Compositae)*
Authors: Vetter S. , Franz Ch. , Giasl S. , Kastner U. , Saukel J. , Jurenitsch J. 
Published: April 2006

AbstractSuccessful crossing experiments between tetraploid individuals of Achillea ceretanica, A. collina, A. distans ssp. styriaca, and A. pratensis (A. millefolium complex, Compositae) were carried out. Sesquiterpenes of 1013 hybrid plants obtained from 13 crossings were studied by qualitative thin layer chromatography (TLC). F1‐progenies from parent plants with guaianolides (GU‐type), as well as the offspring of a back‐cross, uniformly contained proazulenes. Diallel crosses between plants exclusively with eudesmanolides (EU‐type) resulted in a 7:1 segregation‐ratio of EU‐ and GU‐plants. Two reciprocal crossing experiments between EU‐ and GU‐parents resulted in 28.6% and 89.3% EU‐individuals, as well as GU‐offspring. According to these findings, the qualitative marker ‘proazulene’ (GU‐type) is thought to be a recessive character of the tetraploid Achillea species studied.
Resistance to Rhynchosporium secalis in six Nordic barley genotypes
Authors: Robinson J. , Jalli M. , Lindqvist H. 
Published: April 2006

AbstractSix six‐row Nordic spring barley genotypes (Hordeum vulgare L.) were assessed in the field in Finland (1994 and 1995) for resistance to Rhynchosporium secalis (Oud.) J.J. Davis, the causal pathogen of scald, in artificially inoculated plots. The barleys were known not to contain major genes for resistance to scald and the purpose of these experiments was to identify quantitative differences in resistance to scald which might be exploitable in a breeding programme. Disease development was monitored, grain yield and yield components were recorded, and these data were compared with measurements taken from plants in plots kept free of disease. Data, averaged over both years, for disease development on the uppermost three leaves — areas under disease progress curves, terminal severity and apparent infection rates — indicated that ‘Verner’, ‘Pohto’ and ‘Pokko’ were symptomatically significantly more resistant to scald than ‘Arve’, ‘Loviisa’ and Jo 1599. Grain yields, thousand‐grain weights, test weights and proportions of plump grains were all significantly reduced in plots inoculated with scald compared with those kept free of disease; ‘Verner’ appeared to be the most useful genotype for use in crossing programmes to improve scald resistance in Finnish barleys.
Enhanced anther culture efficiency of indica rice (Oryza sativa L.) through modification of the culture media
Authors: Raina S. K. , Zapata F. J. 
Published: April 2006

AbstractThe production of microspore‐derived green plants from anther culture of indica rice is generally very low compared with japonica cultivars. A modified anther culture medium, consisting of a higher KNO3 content (31 mm) and casein hydrolysate (CH, 500 mg/1) but without ammonium salts, was tested in comparison with a medium consisting of the widely‐used N6 medium nitrogen background, using four indica × indica F1 hybrids as test materials. Green plant regeneration frequency was at least three‐fold higher in the microspore‐calli derived from the former medium than in those derived from the modified N6 medium. More than 700 microspore‐derived plants were raised in the field. Another study was carried out using indica × japonica and indica × javanica F1 hybrids. The results indicated that a medium with higher (3.5 mm) ammonium sulphate may induce a higher frequency of anthers with microspore‐calli but not necessarily lead to a larger number of green‐plant regenerating calli. Subsequently, using the indica cv. ‘IR‐43’ as the test material, use of a lower level (1.75 mm) of (NH4)2SO4, in addition to KNO3 (31 mm), was found to be better than CH (500 mg/l) for anther‐response as well as green plant regenerability of the derived microspore‐calli. Nitrate‐nitrogen or ammonium‐nitrogen alone elicited poor response. Twenty‐five media involving combinations of KNO3 (20–34 mm) and (NH4)2SO4 (1–3 mm) were tested for their effects on anther response. Combinations involving KNO3 (31–34 mM) and (NH4)2SO4 (2.0–2.5 mm) were found superior not only for achieving greater anther response but also, for subsequent green‐plant regeneration. This contrasts with the 28 mm of KNO3 and 3.5 mm of (NH4)2SO4 in the widely‐used N6 medium developed for japonica rice. Other than potassium nitrate and ammonium sulphate, and potassium phosphate to some extent, the levels of other inorganic salts tested did not make any significant difference to the process of anther response. Based on these results, modified media with three levels of ammonium sulphate were tested for anther culture efficiency of indica × japonica and indica × javanica derivatives (F3s). Microspore‐calli derived from a medium of a lower (1.75 mm) level of (NH4)2SO4 showed a higher regeneration potential overall than those derived from a higher (3.5 mm) level. A revised medium has been suggested, on the basis of these results, for the realization of improved anther culture efficiency and, consequently, improved feasibility of using doubled haploids in genetic and breeding research with indica rice.
Widespread introgression of Solatium phureja DNA in potato (S. tuberosum) dihaploids
Authors: Clulow S. A. , Rousselle‐Bourgeois F. 
Published: April 2006

AbstractDihaploids were assumed to be of parthenogenic origin but cv. ‘Pentland Crown’ dihaploids produced at the Scottish Crop Research Institute (SCRI), Dundee, Scotland, are known to contain DNA from the S. phureja dihaploid inducer. This study investigates whether inducer DNA occurs in dihaploids of cultivars ‘Aminca’, ‘Brio’, ‘Lizen’ and ‘Sirtema’, produced at INRA, Ploudaniel, France. Two microsatellite markers and five simple sequence repeat 5′‐anchored polymerase chain reaction (PCR) primers were used to generate markers. Markers originating from the dihaploid inducer were detected in 13 of the 19 INRA dihaploids and in some dihaploids from each cultivar. Greater introgression occurred in ‘Lizen’ dihaploids than in ‘Brio’ dihaploids, suggesting that the female (S. tuberosum) parent influences introgression. The percentage of INRA dihaploids containing inducer DNA was similar to that for ‘Pentland Crown’ dihaploids (c. 65%). The micro‐satellite markers provided the first evidence of the transfer of specific, potentially useful, genes from the inducer to the dihaploid offspring.Interspecific introgression during dihaploid induction is more widespread than previously thought and researchers should be aware that it may influence the results of research using dihaploids.
Evaluation of FDR diploid and tetraploid parents in potato under two different day‐length environments
Authors: Ortiz R. , Iwanaga M. , Peloquin S. J. 
Published: April 2006

AbstractFive tetraploid clones of potato were crossed to each of eight diploid first division restitution (FDR) 2n pollen producers and four tetraploid males using a line × tester mating design. A total of 59 families were obtained and evaluated under long days at Rhinelander (USA). A subset of 49 families were grown under short days at four Peruvian locations. Tuber yield (kg per plant) of 4x‐2x families was similar to, or greater than, that of 4x‐4x families in short day environments. The diploid clones had breeding values greater than or equal to those of the tetraploid clones. Only families derived from FDR 2n pollinators combined high tuber yield with stability and high dry matter content. Reciprocal recurrent selection would be the best breeding scheme, in which the diploids are testers of the tetraploids and vice‐versa. Intra‐population improvement could be achieved through phenotypic recurrent selection. The best materials from both breeding pools could then be crossed to produce tetraploid hybrids through unilateral sexual polyploidization (4x‐2x crosses).
Effect of genotype and light intensity on somatic embryogenesis and plant regeneration in melon (Cucumis melo L.)
Authors: Kintzios S. E. , Taravira N. 
Published: April 2006

AbstractThe efficiency of 14 commercial cultivars of melon (Cucumis melo L.) for callus induction, plant regeneration and somatic embryogenesis under different photosynthetic photon flux densities (PPFDs) (150 or 50μmol m−2 s−1) was investigated. Cotyledonal explants were cultured on a Murashige and Skoog (MS) medium supplemented either with 9.0 μM 2,4‐dichlorophenoxyacetic acid and 23.2μM kinetin or with 0.05 μM 2,4‐dichlorophenoxyacetic acid and 0.26 μM 6‐benzyladenine for the induction of somatic embryogenesis and shoots, respectively. For embryo maturation and root induction, growing callus tissues were transferred on growth regulator‐free MS medium. Both genotype and the intensity of light significantly affected the rate of somatic embryo‐genesis, embryo maturation and plant regeneration. On average, 12–47 primary globular‐stage embryos were produced per mm2 of explant surface. Fully developed, cotyledonary‐stage somatic embryos were obtained from only three cultivars. Relatively high root induction rates were observed both on the shoot induction medium (11 cultivars) and on growth regulator‐free medium (seven cultivars). In contrast, only six cultivars responded positively to the shoot induction treatment. Callus growth and somatic embryogenesis were significantly improved if cultures were incubated under higher PPFD values, although plant regeneration from all cultivars was significantly reduced under the same conditions.
Absence of a genetic relationship between salt tolerance during seed germination and vegetative growth in tomato
Authors: Foolad M. R. , Lin G. Y. 
Published: April 2006

AbstractTwo approaches were used to determine the relationship between salt tolerance during seed germination and vegetative growth in tomato. First, F4 progeny families of a cross between a breeding line, ‘UCT5’ (salt sensitive at all developmental stages), and a primitive cultivar, ‘PI 174263’ (salt tolerant during germination and vegetative growth), were evaluated in separate experiments for salt tolerance during germination and vegetative growth. There were significant differences among the F4 families in both the rate of seed germination and the plant growth (dry matter production) under salt stress. There was, however, no significant correlation between the ability of seeds to germinate rapidly and the ability of plants to grow under salt stress. In the second approach, selection was made for rapid germination under salt stress in an F2 population of the same cross and the selected progeny was evaluated for salt tolerance during both germination and vegetative growth. The results indicated that selection for salt tolerance during germination significantly improved germination performance under salt stress; a realized heritability estimate of 0.73 was obtained. Selection for salt tolerance during germination, however, did not affect plant salt tolerance during vegetative growth; there was no significant difference between the selected and unselected progeny based on either absolute or relative growth under salt stress. Obviously, in these genetic materials, salt tolerance during germination and vegetative growth are controlled by different mechanisms. Thus, to develop tomato cultivars with improved salt tolerance, selection protocols that include all critical developmental stages would be desirable.
Efficiency of various insects in germplasm regeneration of carrot, onion and turnip rape accessions
Authors: Schittenhelm S. , Giadis T. , Rao V. R. 
Published: April 2006

AbstractSeed regeneration is one of the most important tasks in genebank work. To regenerate germplasm of allogamous, entomophilous plant species in isolation facilities, insects are often used as pollen vectors. The objective of this study was to determine the effect of pollinator species, pollinator densities, pollinator combinations, and flower preferences on the seed quantity and quality of Daucus carota, Allium cepa, and Brassica rapa. The isozyme phosphoglucoisomerase (PGI) served as genetic marker in determining outcrossing rates and pollen dispersal distances. Field plots and isolation cages without insects were used as controls. The pollinators studied consisted of the following insect species from German native fauna: red mason bees (Osmia rufa L.), hoverflies (Eristalis tenax L.), and blowflies (Calliphora sp. and Lucilia sp.). In D. carota and B. rapa, higher seed yields were achieved in isolation cages than in field plots, but in A. cepa lower seed yields were obtained in the isolation cages. Although O. rufa showed no liking for A. cepa, unintentional pollination was effected by this insect in isolation cages. Lower insect densities were necessary for O. rufa than for the various fly species.