bluuebunny/crossref_metadata_2025 huggingface dataset:
An Economic Investigation of Early‐Generation Quality Testing in a Wheat Breeding Program
Authors: Brennan J. P. , O'Brien L.
Published: April 2006

Public plant breeders, in seeking the most efficient means of achieving their objectives, face decisions on the appropriate breeding strategy and program structure to use. This paper reports an analysis comparing the changes in costs and benefits from the introduction of recent technology enabling testing for flour and dough properties to be carried out on small samples in the early‐generations of a wheat breeding program in Australia. The average costs of a suite of early‐generation tests are higher than the equivalent (unreplicated) yield testing. The analysis presented confirms that the introduction of early‐generation quality testing leads to a faster rate of expected progress in quality, but a slower rate of progress in yield. The estimated market value of an increase in yield is greater than that for quality, based on current market information. Thus, the result of incorporating early‐generation quality testing is higher costs and lower expected returns, so that there is a loss of community welfare from using early‐generation quality testing if the resultant cultivar is released from each program. However, the probability of the higher‐quality cultivar being released for commercial cultivation is greater, so that recognition of the probability of release means that there may be net gains from the use of early‐generation quality testing.
Identification of a Monogenic Dominant Male Sterility Mutant in Broccoli (Brassica oleracea var. italica Plenck)
Authors: Dunemann F. , Grunewaldt J.
Published: April 2006

After mutagenic treatment with NMU (nitroso‐methylurea) flower buds and flower‐bud pedicels of broccoli were cultivated in vitro. Among regenerated MJ plants, one male sterile, but female fertile mutant was found, for which a monogenic dominant inheritance of male sterility was demonstrated. A scheme to utilize dominant controlled genie male sterility in Brassica oleracea for hybrid breeding is discussed.
Genetic Variations and Adaptations in Chickpea
Authors: Bahl P. N. , Kumar J. , Raju D. B.
Published: April 2006

A total of 329 chickpea lines, comprising 130 kabiili and 199 desi types, originating from six regions, viz., Indian sub‐continent, Middle East, North Africa, America, Europe and USSR, were sown in augmented design. The data recorded on agronomic characters on all entries from each region were evaluated in terms of group (region) means. Among the six regions, greater plant height and lateness in flowering were specific to USSR entries. Group means of USSR accessions, both desi and kabuli, differed significantly from those of Indian varieties for a majority of the characters. These observations indicate that the degree of expression of certain characters could be ascribed to specific areas, which led to area‐specific adaptations. Furthermore, type‐specific differentiating characters, differing in degree of expression, were observed in desi and kabuli types. For example, high mean values of characters, like branches, pods, grain yield and harvest index, were associated with desi types, and 100‐seed weight with kabulis. History of cultivation and selection for specific purpose has been cited as cause for area‐specific adaptations and type‐specific differentiating characters.
The Use of RFLPs (Restriction Fragment Length Polymorphisms) Detects Germplasm Introgressions from Wild Species into Potato (Solanum tuberosum ssp. tuberosum) Breeding Lines
Authors: Debener T. , Salamini F. , Gebhardt Christiane
Published: April 2006

The germplasm of the potato (S. tuberosum ssp. tuberosum) has been modified since the beginning of this century by breeders who introgressed important agronomic traits, for example disease resistance genes, from several wild and cultivated Solanum species of the Americas. In this paper we show that the Rflp analysis of potato‐breeding material can be used to detect chromosomal regions descended from more‐distantly related Solanum species. The Rflp patterns of individuals of ten Solanum species, ten breeding lines of S. tuberosum ssp. tuberosum and the cultivated variety ‘Bintje’ were analyzed. Rflp data for each of eight single loci of known genomic position were used for the computation of locus‐specific phenograms by distance matrix methods. Several of the potato‐breeding lines deviated clearly from the clustered species S. tuberosum, S. stenotomum and S. canasense for one or more of the loci considered. These deviations indicated the presence of “exotic” germplasm at a particular locus. The possibility of detecting such germplasm has implications for mapping the agronomic traits for which the wild species were introgressed and which may still be linked to “foreign” chromosome fragments.
High Frequencies of Fertilization and Haploid Seedling Production in Crosses Between Commercial Hexaploid Wheat Varieties and Maize
Authors: Laurie D. A. , Reymondie Sylvie
Published: April 2006

Nineteen commercial hexaploid wheat varieties were crossed with the maize F1 hybrid ‘Seneca 60’. Fertilization frequencies ranged from 32.1 % to 47.5 % of pollinated florets (mean 39.5 %) in the 14 winter wheat varieties and from 40.7 % to 51.4 % (mean 47.8 %) in the five spring wheat varieties. In some cases only an endosperm was formed and the frequencies of embryo formation were therefore slightly lower, being 28.2 % to 45.9 % (mean 36.4 %) for winter wheats and 39.8 % to 48.6 % (mean 45.1 %) for spring wheats. Mean values were significantly higher in the spring wheats but no significant variation was found between varieties within the spring or winter categories. In the five spring wheats the mean yield of embryos, and hence the potential yield of haploid plants, was 3.4‐fold higher than with the tetraploid Hordeum bulbosum clone PB179. For the 14 winter wheats the figure was 10.9‐fold higher. These differences were highly significant (p < 0.001) in all varieties. A single 2,4‐D treatment given to spikes one day after pollination with maize enabled embryos to be recovered from all 19 varieties. A total of 311 embryos were recovered from 950 florets (an average of 7.3 embryos per spike) of which 191 germinated, giving an average yield of one haploid plant for every 5.0 florets pollinated (4.4 haploid plants per spike).
Genome Size Variation in Maize Populations Selected for Cold Tolerance
Authors: McMurphy L. M. , Rayburn A. Lane
Published: April 2006

Previous studies have indicated a relationship between genome size and cold tolerance in plants. Many species adapted to growth in cool environments have large genome sizes. These studies are based on interspecific DNA content variation. In this study, the nuclear DNA content of eight maize populations was determined. These populations were obtained from the University of Nebraska and represent populations selected for cold tolerance and their respective unselected original populations. Intraspecific DNA content variation was observed between the selected and unselected populations. Upon assessing the data based solely on cold tolerance, no clear relationship between genome size and cold tolerance was apparent. When both freeze tolerance and cold tolerance were considered, populations which were cold tolerant and exhibited a certain degree of freeze tolerance were observed to have significantly larger genomes relative to the unselected populations. Thus, it appears that the relationship between intraspecific genome size variation and cold tolerance is similar to the relationship between interspecific genome size variation and growth at cooler temperatures in plants.
Quantitative‐Genetic Basis of Sprouting Resistance in Rye
Authors: Wehmann Frauke , Geiger H. H. , Loock A.
Published: April 2006

The quantitative‐genetic basis of sprouting resistance in winter rye (Secale cereale L.) was investigated in order to facilitate breeding for improved baking quality. Crosses within and between the Petkus and Carsten gene pools were tested along with the parental lines over two locations, two years, and two harvest dates. Heritabilities of approximately 0.6 were found for falling number (FN), a‐amylase activity, dormancy, and amylograph curve characters. FN showed moderate heterosis that reached 35%. High genetic variation for FN was observed in most genetic materials, and error variances were generally small. Considerable genotype × year interactions occurred. Genotypes with high FN showed more instability for FN over environments. General combining ability was the main source of genetic variation for FN (80%) and was correlated with line per se performance in the Carsten gene pool (r = 0.66). FN showed moderate to strong correlations with slowness of development, but only loose ones or none with other agronomic traits. We conclude that improving sprouting resistance by selecting for FN should be highly effective and would not cause unfavourable side effects with regard to yielding performance.
Germplasm Assessment in Trifolium Species
Authors: Fay M. F. , Mytton L. R. , Dale P. J.
Published: April 2006

Populations of 64 taxa of Trifolium were assessed for nitrogen fixation and dry matter production with and without added mineral nitrogen. The number of rhizobia per gram of compost capable of inducing nodulation was tested in 7 species and ranged from 3 to 114, showing interspecific variation for nodulation with indigenous rhizobia. In a sample of 8 species, nitrogen fixation was assessed by acetylene reduction and nodule scoring. There was a good correlation (84 %, P ≤ 0.01) between the two methods, and therefore nodule score was used as a measure of nitrogen fixation in the main assessment. There were large differences between populations in terms of shoot and root dry weight, the shoot: root ratio and nodule score. Added nitrate had a significant effect on all characters, increasing shoot dry weight and the shoot: root ratio and decreasing root dry weight and the nodule score. Results showed the importance of assessing legume germplasm with and without added nitrate in locations where suitable rhizobia for the nodulation of exotic species might not be present.
Variabilité Génétique de Certains Paramètres de la Qualité Brassicole de l'Orge
Authors: Garcera L. , Sarrafi A. , Jestin L. , Ecochard R.
Published: April 2006

Genetic Variability for Some Brewing Quality Characters in Barley Malting and brewing quality of six different barley genotypes and their F1 hybrids were investigated in a diallel cross programme. Plants were grown in pots in a randomized block design with four replications. General and specific combining abilities were determined for 1000 grain weight, percentage of proteins of the grain, percentage of water uptake, and, after micromalting, for β‐glucanase and α‐amylase activities. Significant general and specific combining abilities were observed for all the traits studied. 1000 grain weight, percentage of proteins and water uptake have been found to be essentially controlled by genetic additive effects, while enzymatic activities of malt have been found to be mostly controlled by dominance effects. ‘Karl’ has interesting characteristics for all traits and general combining abilities, except for 1000 grain weight, and has been introduced in a three‐way cross programme with ‘Plaisant’ and ‘Clarine’, also showing interesting values for malting quality and productivity.
Analysis of Factors that Influence Kernel Weight of Wheat Infected by Septoria nodorum
Authors: Scharen A. L. , Lund R. E. , Dietz‐Holmes M. E.
Published: April 2006

Several methods for determining yield reduction resulting from Septoria nodorum blotch have appeared in the literature during the past decade. These methods varied from the measurement of effects of disease on components of yield to calculation of area of symptoms on certain leaves at different growth stages. We analyzed data from a uniform group of wheat entries in the USDA Septoria nursery that had been grown in seven locations in North America and Europe during the years 1982–1987. Symptom severity and height of symptom on the plant were compared to kernel number and kernel weight. Location, year‐within‐location and genotype were also considered. In the context of this study, we concluded that location, and year‐within‐location are the most important factors determining yield reduction (as measured by relative kernel weight). Selection directly for components of yield is quite effective, but selection by means of disease symptoms is often not correlated with yield. We also conclude that specific methods for relating symptoms to yield reduction that are applicable to a particular location are probably useful and appropriate for that location only.
Genetic Variation of the Content of Sinapoyl Esters in Seeds of Rape, B. napus
Authors: Kräling K. , Röbbelen G. , Thies W.
Published: April 2006

A broad spectrum of rapeseed (rape) lines as well as resynthesized (resyn) genotypes of B. napus were analyzed for their contents of sinapoyl esters. In the rape material the concentrations varied between 17.8 and 71.9 μol/g defatted seed meal and exhibited a heritability of h2= 0.6. The resyn genotypes showed an even smaller variation but had a similar heritability. Therefore, no additional, immediately usable, genotypes with low sinapoyl ester concentrations could be created by a resynthesis.
A Simple Device to Prepare Single Ears of Spelt (Triticum spelta L.) for Seeding with the “Seedmatic‐System”
Authors: Bleiker Ursula , Winzeler H.
Published: April 2006

Spelt is usually planted as spikelets. These cannot be obtained by the threshing machines generally used for bread wheat. With a simple device it is possible to separate single ears of spelt into spikelets ready for sowing. At the same time, it is possible to score the fragility of the rachis and the degree of free thresh‐ability, both important characteristics for the selection of spelt.
Associations between 23 Quantitative Traits and 10 Genetic Markers in a Barley Cross
Authors: Kjaer B. , Haahr V. , Jensen J.
Published: April 2006

Associations of 23 quantitative traits and 10 genetic marker characters were examined in 63 chromosome‐doubled lines (DH‐lines) derived from the F1‐ generation of a cross between an old and a modern spring barley variety. One fourth of the marker × trait combinations showed significant associations. More than two thirds of these associations were to earliness (heading date). Earliness was found to be controlled by two loci: the previously known eak locus and a new locus designated Ea. It is concluded that the associations of quantitative traits with the earliness loci were caused by pleiotropy. Associations were found between two absolutely linked C‐bands on chromosome 3 and QTLs (quantitative trait loci) for lodging, straw diameter, and length of top internode of the straw. The three loci on chromosome 5, eak and the two linked powdery mildew loci, Mla9 and Mlk, were associated with a possible QTL for magnesium concentration in grain. Association to the C‐band on chromosome 6 suggests QTLs for TGW (thousand grain weight), straw diameter and magnesium concentration in grain. Locus Estl on chromosome 3 was not associated with any of the quantitative traits.
A New Intergeneric Hybrid between Triticum aestivum L. and Agropyron fragile (Roth) Candargy: Variation in A. fragile for Suppression of the Wheat Ph‐Locus Activity
Authors: Ahmad F. , Comeau A.
Published: April 2006

New intergeneric hybrids were obtained between Triticum aestivum L. cv. Tukuho’ (2n = 6x = 42, AABBDD) and Agropyron fragile (Roth) Candargy PGR 8097 (2n = 4x = 28, PPPP) at a frequency of 1.06 %, through the use of direct embryo culture and in ovulo embryo culture. Such hybrids could be used to transfer barley yellow dwarf virus (BYDV) resistance and winterhardiness into bread wheat. The somatic chromosome number in all the hybrid plants was 2n = 5x = 35, as expected. Considerable variation in chromosome pairing was observed among the different hybrid plants. Average meiotic chromosome configuration at metaphase I was 17.29 Is + 6.57 rod Us + 1.97 ring Us + 0.18 III + 0.03 IV + 0.002 VI. The high level of chromosome pairing in some F1 hybrids was attributed to Ph‐suppressor gene(s) present in A. fragile. The hybrids could not be backcrossed to wheat, but amphiploid seeds have been obtained by colchicine treatment.
Estimation of the Isozymatic Genetic Variability of a Spanish A vena sativa Germplasm Collection
Authors: Gomez C. , De Miera L. Saenz , De La Vega M. Perez
Published: April 2006

An analysis of Spanish land races of Avena sativa from the Germplasm Bank of the I.N.I.A. was carried out using starch gel electrophoresis. Samples of 15 seedlings per accession were used for estimating the intra‐ and interpopulational genetic variability. Electrophoretic analyses were performed with crude extracts from 15 day‐old seedling leaflets by means of eight isozymatic systems representing a total of ten genetic loci. Two systems were mono‐morphic in all the accessions, while the other six showed polymorphism both within and between populations. Intrapopulational variability was particularly high in this collection, only 16 out of the 137 accessions being uniform for all the isozyme systems. Thus the material was shown to represent a high potential of genetic variability for breeding programmes.
Selection for Increased Seed Nitrogen Accumulation in Common Bean: Implications for Improving Dinitrogen Fixation and Seed Yield
Authors: Miranda B. D. , Bliss F. A.
Published: April 2006

Estimates of N2 fixation in segregating populations of bean plants based on 15N‐isotope methods are technically demanding and expensive; therefore, indirect measures based on related traits including total seed N were used to select for improved N2 fixation and yield. In 1985, six populations of F2‐derived F3 families resulting from six parental lines crossed to a common tester were grown in field trials on a low‐N soil. In 1986, 25 selected half‐sib families and two populations of full‐sib F4 families were grown under similar conditions. Parents and a non‐nodulating soybean line were included both years. Narrow sense (HNS) heritability estimates based on parent‐offspring regressions ranged from 0.57 for total seed N to 0.39 for shoot biomass in one population, but were near zero for all measured traits in a second population. Among the criteria used to identify parental lines with superior potential for producing progenies with high total seed N, testcross population means combined with estimates of realized heritability were the most reliable. Selection of the best F3 families for total seed N resulted in F4 families with increased total seed N and higher seed yields, while seed protein percentage was unchanged. When plants are grown on low‐N soils, selection for total seed N offers a useful alternative to selection for increased N2 fixation based on 15N‐isotopic or total‐N‐difference method.
Independent, Alternate, and Simultaneous Selection for Resistance to Anthracnose and Angular Leaf Spot and Effects on Seed Yield in Common Bean (Phaseolus vulgaris L.)
Authors: Singh S. P. , Pastor‐Corrales M. A. , Molina A. , Urrea C. , Cajlao C.
Published: April 2006

Two double‐cross populations were used to evaluate the efficiency of independent, alternate, and simultaneous selection practiced from the F2 to F8 for resistance to anthracnose and angular leaf spot of common bean (Phaseolus vulgaris L.). Seven resistant and high‐yielding lines were selected from each of the four environments used during this study. These lines and the seven parents involved in two populations were evaluated in an 8 × 8 lattice design with three replications in two cropping seasons. Pathogen inoculum was used to create the three test environments: anthracnose alone, angular leaf spot alone, and anthracnose and angular leaf spot together. All entries were also evaluated in a fourth, disease‐free environment. Selection for resistance to anthracnose and angular leaf spot was effective in both populations. Mean disease scores of all selected lines for anthracnose were lower than that of angular leaf spot irrespective of selection environment. Among the three stress environments, yields were higher in the anthracnose environment. However, lines selected alternately for anthracnose and angular leaf spot were usually higher yielding, and the highest yielding line in both populations originated from this selection environment. The mean yield of selected lines was higher and the highest yielding line originated from the population involving a parent (G 1805) belonging to the Mexican highland race ‘Jalisco’. Positive association existed between seed yield of protected and pathogen‐inoculated environments. No association was found between resistance to anthracnose and angular leaf spot.
Androgenesis in Hexaploid Spring Wheat F2 Populations and Their Parents Using a Multiple‐Step Regeneration System
Authors: Pauk J. , Manninen O. , Mattila I. , Salo Y. , Pulli S.
Published: April 2006

The main goals of the wheat androgenesis experiment were to study the main phenomena of in vitro androgenesis in anther culture of F2 populations (10) and their parents (6), to compare the usage of P‐4 and C‐17 media for the formation of embryo/callus and to demonstrate a new plant regeneration system.

The P‐4 induction medium was found to be significantly better than the C‐17 in the number of responsive anthers (RA) and calli induced (CI) at the 1 % and 0.1 % level, respectively. Genotypic effect was evident in both RA and CI. The yields of F2 populations in RA and CI were significantly higher than those of their parents regarding both media. The data confirmed the existence of heterosis for RA and CI in F2 populations.

The ratio of green/albino plant regeneration was more favourable in the C‐17 derived embryo/calli than in the P‐4 derived ones.

The frequency of plantlet regeneration was enhanced in the group of unresponsive calli by the application of the multiple‐step regeneration system. In this system the calli lacking well developed morphogenic structure were transferred to a new regeneration medium, containing a higher concentration of the same cytokinin, other cytokinin or basic medium, before the occurrence of irreversible changes in their physiology.
Resistance to Phytophthora infestans in Potato Genotypes Originating from Wild Species
Authors: Swiezynski K. M. , Sieczka M. T. , Sujkowski L. S. , Zarzycka H. , Zimnoch‐Guzowska E.
Published: April 2006

The reaction to P. infestans in the foliage and tubers of potato was evaluated in resistant genotypes and in their progeny. The genotypes originated from wild species known to carry genes for specific resistance.

Evidence was obtained that three types of resistance to P. infestans were presented in the genotypes: (1) Resistance due to major, dominant genes was predominant. The presence of these genes was expressed in both foliage and tubers and did not influence maturity. Some of the genes were R genes, providing specific resistance, but for others this could not be determined as they were effective against the fungus inoculum with the highest virulence available: 1.2.3.4.5.7.10.11. (2) Resistance was present, associated with late maturity. (3) Tuber resistance was present, expressed after inoculation of whole tubers but not after inoculation of tuber slices.

Testing of the progeny was essential for the determination of the type of resistance present in the genotypes evaluated.
Genotype × Environment Interaction for Nitrate Concentration in Lettuce
Authors: Reinink K.
Published: April 2006

High nitrate concentration is a problem when lettuce (Lactuca sativa L.) is grown under low light intensities. Genotypes with low nitrate concentrations have been identified and are being used in breeding programmes. Previous results indicated the occurrence of genotype × environment (GE) interactions. Because of the important influence of light intensity on nitrate accumulation, two types of interactions may be expected: interactions related to daily variation, and those related to annual variation. In the present investigation both types were investigated using eight butterhead genotypes of lettuce which were repeatedly harvested. No daily variation in nitrate concentration and no corresponding GE‐interactions were found, irrespective of the level of global radiation. In contrast, a large annual variation and important corresponding GE‐interactions were found. Joint regression analysis on environmental means and on physical factors related to light intensity showed a differential response of genotypes to changing environmental conditions. Multiple joint regression on daylength and change in daylength accounted for two‐thirds of the interaction variance. However, deviations from regression were still significant indicating non‐linearity of the relationship, or, the existence of other environmental factors contributing to GE‐interaction.
Genetics of Resistance to Phytophthora capsici in the Pepper Line ‘SCM‐334’
Authors: Ortega R. Gil , Español C. Palazóon , Zueco J. Cuartero
Published: April 2006

In order to establish a genetic model of the resistance to Phytophthora capsici in Capsicum annuum genotype ‘SCM‐334’, two experiments were conducted which included ‘SCM‐334’, as well as, the susceptible line ‘Morrón INIA 224’ and their Fl, F2, F3 and BC1 generations. We also tried to introgress a recessive gene, hypothetically responsible for resistance to P. capsici, from ‘SCM‐334’ into ‘Morrón INIA 224’. Inoculations were made, when plants had 4—6 leaves, by irrigating the culture substrate with a zoospore suspension of P. capsici isolate ‘Bl’. The χ2 test was applied to segregating generations to determine how many genes were involved in resistance. The hypothesis which explained the obtained segregations best, although not completely, was one that assumes 3 genes in ‘SCM‐334’;, with at least 3 alleles in the heterozygous condition or 4 at any position, present in any genotype in order to be resistant. The influence of the isolate's aggressiveness and the inoculation method on the results are discussed.
Reproductive Behavior of Hexaploid/Diploid Wheat Hybrids 1
Authors: Cox T. S. , Harrell L. G. , Chen P. , Gill B. S.
Published: April 2006

The bottleneck restricting introgression of useful genes directly from diploid into hexaploid wheats is the low number of BC1F1 seeds obtained. In crosses between hexaploid wheat (Triticum aestivum L.; AABBDD) and Aegilops squarrosa L. (DD) or T. urartu Thum. (AA), this bottleneck may be overcome simply by pollinating a sufficient number of F1 spikes. However, hybrids between hexaploid wheat cultivars (T. aestivum) and T. monococcum L. (AA) generally are highly female‐sterile, often having no pistils. One T. monococcum accession, PI 355520, when crossed with T. aestivum, produced hybrids with female fertility in the same range as that of T. aestivum/A. squarrosa or T. aestivum/T. urartu hybrids, ca. 0.5 to 1.0 backcross seed per spike. We found that female fertility was controlled by two duplicate genes in PI 355520, and that this accession can be used as a bridging parent to introgress genes from other T. monococcum accessions into hexaploid wheat. Pairing of homologous chromosomes was less frequent and weaker in such crosses than in T. aestivum/A. squarrosa crosses, but homoeologous bivalents occurred at a rate of almost 0.5 II per cell. Restitution division was detected in crosses involving all three diploid species and was confirmed cytologically in crosses with PI 355520. Chromosome numbers of BC1F1 plants ranged from 35 to 67; plants with 49 or more chromosomes occurred at frequencies of 0.09 to 0.21 among progeny of A. squarrosa and T. urartu and 0.29 in progeny of T. aestivum/T. monococcum crosses involving PI 355520. These results are consistent with those of previous studies, demonstrating the potential of direct Hexaploid/diploid crosses for rapidly introgressing useful genes into Hexaploid wheat with minimum disturbance of the background genotype.
Genetic Control of Five Isozyme Systems in Sugar Beet (Beta vulgaris L.)
Authors: Wagner H. , Wricke G.
Published: April 2006

Genetic markers are most useful in plant breeding but so far only a few morphological and isozyme markers are known in Beta vulgaris. In this paper, the isozyme systems aconitase (AGO), NADH‐:dihydrolipoamiddehydrogenase (DIA), esterase (EST), fructose‐1,6‐bisphosphatase (FDP), and hexokinase (HK) were genetically analysed. Isoelectric focussing (IEF), vertical polyacrylamide gel electrophoresis (PAGE) and starch gel electrophoresis (SGE) were used to separate the isozymes. A total of eight loci could be identified. The allelic forms of Aco‐1, Dia‐1, Est‐1, Est‐5 and Hk‐1 are active monomers. The gene products of Est‐3 and Fdp‐2 are active as dimers. Est‐2 also showed allelic forms without activity; null‐alleles.
Methods for Selection of Low‐Temperature Tolerant Mutants of Chrysanthemum morifolium Ramat. Using Irradiated Cell Suspension Cultures III. Comparison of Mutants Selected with or without Preselection in vitro at Low‐Temperature
Authors: Huitema J. B. M. , Preil W. , De Jong J.
Published: April 2006

One hundred variants of Chrysanthemum morifolium cv. ‘Parliament’, selected on a single plant basis for early flowering at low temperature, were tested on a clonal basis. These variants originated from irradiated or non‐irradiated microcalli subjected to a one‐step greenhouse selection procedure, or, a two‐step selection procedure (preselection in vitro at 6°C followed by selection in the greenhouse). Clones originating from irradiated calli flowered significantly earlier than the controls. Most of the low‐temperature tolerant (LTT) mutants were found among plants obtained by the one‐step selection procedure. Variants originating from slowly regenerating calli yielded more LTT mutants as compared to those of fast(er) regenerating calli. We therefore conclude that, irradiation and subsequent selection of plants from slowly regenerating calli considerably increases the efficiency of selecting LTT mutants. The expected advantage of a preselection in vitro at low‐temperature could not be confirmed.
Genotype × Environment Interaction in the Andean Grain Crop Quinoa (Chenopodium quinoa) in Temperate Environments
Authors: Risi J. , Galwey N. W.
Published: April 2006

Ten varieties of quinoa with origins ranging from latitude 39° S to 12° S and from sea level to an altitude of 3,800 m were grown on two soil types in two years in Cambridgeshire, England, in order to assess the extent and nature of genotype × environment (G × E) interactions and identify genotypes suited for cultivation at temperate latitudes. There was evidence that varieties differed in their susceptibility to water logging during germination. Plant height was strongly influenced by competition with weeds, and varieties differed in their susceptibility to this. The number of days to anthesis and to maturity were strongly dependent on the variety, but these periods were generally longer following an earlier sowing. The grain yield was also strongly dependent on the variety, but weed competition, a micronutrient deficiency and bird damage affected the varieties differently. Varieties originating at high latitudes gave the highest yields, about 5,000 kg/ha. Earliness and yield were strongly associated at the level of variety means, but the pattern of G × E interaction differed among the variables measured.
Expected Response to Selection in Synthetic Populations of Perennial Ryegrass
Authors: Charmet Gilles , Ravel Catherine Grand
Published: April 2006

Confidence intervals for heritability and expected genetic advance of seven agronomic traits in two populations of perennial ryegrass have been computed in two ways (a = bootstrap method; b = parametric method) for five different combinations of selection. Two conclusions can be drawn from our results:

Superiority of individual selection over family or every combination of selection.

Usefulness of methods based on resampling to estimate confidence intervals for genetic parameters without particular statistical hypotheses.
The Rate of Outcrossing in Grain Amaranths
Authors: Agong S. G. , Ayiecho P. O.
Published: April 2006

Studies of intra specific and inter specific out crossing rates were carried out for grain amaranths using two populations of A. hypochondriacus (populations 1008 and 1024) and two populations of A. cruentus (populations 1034 and 434). The studies were conducted at Kabete Campus, University of Nairobi and National Horticultural Research Station, Thika, during the months April to August 1988 and October 1988 to February 1989. The mean intra specific out crossing rate estimates for A. hypochondriacus and A. cruentus were 10.4 % and 10.9 % respectively. The mean inter specific out crossing rate involving population 1024 as the dominant marker parent and 1034 as the recessive marker was 1.2 percent. The study involving population 434 as the dominant marker parent gave the mean inter specific out crossing rate as 6.5 percent. The intra specific and inter specific out crossing rate estimates showed substantial variation. Significant differences in out crossing rate estimates were noted due to locational and seasonal variations. The factors probably contributing to the variations were believed to be locational and seasonal differences in pollinator density and differences among the populations.
Inheritance of the Powdery Mildew Resistance Gene Pm9 in Relation to Pm1 and Pm2 of Wheat
Authors: Schneider Dorothee M. , Heun M. , Fischbeck G.
Published: April 2006

The inheritance of the powdery mildew resistance gene Pm9 originating from the hexaploid spring wheat cultivar ‘Normandie’ was analyzed in relation to Pm1 and Pm2.

Two leaf segments of individual P1−, P2−, F1− and F2‐plants of the cross ‘Normandie’ (Pm1, 2, 9) ×‘Federation’ (no known Pm gene) were inoculated separately with two powdery mildew isolates. Using powdery mildew isolate No. 6 virulent for Pm1 and Pm2 but avirulent for Pm9, a 1 resistant (r): 3 susceptible (s) F2‐segregation was found for the Pm9 gene. Using powdery mildew isolate No. 3 virulent for Pm1 and Pm9 but avirulent for Pm2, a 3 (r): 1 (s) F2‐segregation was found for the Pm2 gene. Combining the data of both experiments (leaf segments of identical plants had been used), a 9 (sr): 3 (ss): 3 (rr): 1 (rs) segregation resulted for the F2 of this cross: therefore, independent inheritance of the genes Pm2 and Pm9 can be concluded.

Similarly, the cross ‘Mephisto’ (Pm1, 2, 9) ×‘Amor’ (no known Pm gene) was analyzed. The Pm9 gene again showed a monogenically recessive inheritance, whereas Pm1 showed a monogenically intermediate segregation upon inoculation with powdery mildew isolate No. 9a virulent for Pm2 and Pm9 but avirulent for Pm1. Combining the single gene segregations, linkage between both genes was found among the progenies. A distance of 8.5 cM was calculated.

Analyzing a set of spring wheat cultivars with seven defined powdery mildew isolates, the presence of Pm1, Pm2 and Pm9 in these lines was verified; in most cases, Pm1 occurred together with Pm9.
Improved Culture System for Microspores of Barley to Become a Target for DNA Uptake
Authors: Kuhlmann Ursula , Foroughi‐Wehr Bärbel , Graner A. , Wenzel G.
Published: April 2006

For the winter barley cultivar ‘Igri’, a microspore isolation and regeneration procedure is described which allows the production of such vigorous micro‐spore fractions that this single‐cell system can be used as a target for DNA uptake. Up to 60 % of the vigorous microspores isolated from the anther, and cultured in liquid modified MS medium, formed embryoids and/or calli. Such preparations were used for trials in DNA uptake with the plasmid pBI 221. Transformation trials were performed with polyethylene glycol as the inducing agent. With this treatment, a relative increase of fluorescence could be shown under UV light indicative of transient expression of the uidA gene.
Selection of Semidwarf, Early Maturing and Blast Resistant Mutants after Mutagenic Seed Treatment in Two Locally Adapted Indian Rice Cultivars
Authors: Bansal V. K. , Katoch P. C.
Published: April 2006

The objective of this study was to induce semidwarf, early maturing and blast resistant mutants in two adapted Indian rice cultivars. Seeds of the rice cultivars ‘Madhu Malti’ and ‘Phul Patas 72’ were treated with gamma rays and ethyl methane sulfonate (EMS) as well as a combination of gamma rays and EMS. A total of 96 dwarf (< 75 cm) and semidwarf (< 100 cm) and 104 early flowering/maturing M2 plants were identified among the 18,060 M2 plants observed. Sixty‐eight blast resistant M2 plants were also identified. The true mutant status of these plants has yet to be determined in progeny tests. The induction of desired mutant types in locally adapted cultivars could prove to be superior over their introduction from non‐adapted foreign materials via backcrossing in that the important agronomic characteristics of adaptation to the local environment are retained in the mutants.
Three‐Way and Four‐Way Recurrent Selection in Plant Breeding
Authors: Gallais A.
Published: April 2006

Three or four‐way recurrent selection is proposed for the development of three or four‐way crosses. In term of genetic effects, it could be justified if there are interactions between more than three genes, whether alleles or not, if autopolyploids are also considered. For autotetraploids, in particular with tetragenic interaction, four‐way recurrent selection could be more effective than reciprocal recurrent selection (two‐way selection). According to the types of progenies used to develop the tests, different selection procedures are considered, the two extremes being called method 1 and method 3. With method 1 (selection for three or four‐way general combining ability) a plant from a population is used to produce three‐way or four‐way progenies with the other populations used as testers. With method 3 (selection for three or four‐way specific combining ability) three‐way or four‐way crosses are developed with one plant from each population. To study the genetic advance, the theory is developed to consider either diploidy or autotetraploidy. It is shown that method 3 will allow a greater genetic advance than method 1 for low heritability and low selection intensity. The way towards hybrid development with three and four‐way pedigree selection is discussed: again selection can be for general or specific three or four‐way combining ability. It is emphasized that an advantage of recurrent selection for three or four‐way specific combining ability is that it allows direct varietal development with pedigree selection on three or four‐way specific combining ability. Some other practical aspects are also considered.
A DNA Probe for Rapid Screening of Sugar Beet (Beta vulgaris L.) Carrying Extra Chromosomes from Wild Beets of the Procumbentes Section
Authors: Jung C. , Herrmann R. G.
Published: April 2006

Genes from wild species of the Procumbentes section can be transferred to sugar beet chromosomes via translocations. Since large translocations, including for example a gene for nematode resistance, generally result in meiotic disturbances, there is a need to select new diploid resistant beets from progenies of monosomic wild beet addition lines. A dispersed repetitive DNA probe, which is closely correlated with the resistance gene and hybridizes exclusively with wild beet DNA, appears to be highly superior to selection based on isozyme markers. Characteristic ‘fingerprints’ on the available monosomic addition lines reveal the existence of at last 5 different chromosomes in the wild species each housing a gene for nematode resistance. This probe can be used advantageously to identify individuals carrying the intact or fragmented wild beet chromosomes, or even various amounts of translocated chromatin. Strategies are discussed for the identification of new translocation types using straightforward squash dot or Southern hybridization techniques in combination with the wild beet DNA probe.
Crosses Involving W. Rimpau's Triticale
Authors: Franke R.
Published: April 2006

One hundred years after the creation of the first true triticale crosses of Rimpau, several recent cultivars of triticale and rye have been crossed with two of them. Recombinants of the awned type of Rimpau's triticale (10) with ‘Grado’, ‘Lasko’ and ‘Otello’ exhibited a prolonged vegetative period, a shorter straw, an improved lodging resistance, good yielding capacity and higher disease resistance as compared to ‘Lasko’.
Cross‐Compatibility of Cultivated Adzuki Bean (Vigna angularis) and Rice Bean (V. umbellata) with Their Wild Relatives
Authors: Siriwardhane D. , Egawa Y. , Tomooka N.
Published: April 2006

The wild Ceratotropis species which occur in Japan consist of Vigna angularis var. nipponensis, V. nakashimae, V. riukiuensis and V. reflexo‐pilosa. The main aim of the present study is to detect cross‐compatibility of adzuki bean and rice bean with these wild relatives.

The cross of V. nakasbimae with adzuki bean was successful in both directions and viable seeds were produced, while the cross with rice bean was not successful. V. riukiuensis is cross‐compatible with adzuki bean and rice bean only when V. riukiuensis is used as male parent and the hybrid seeds showed normal germination. The cross between V. reflexopilosa and the two cultigens adzuki bean and rice bean did not succeed in either direction.

The present results suggest that V. nakashimae and V. riukiuensis could be used as gene sources for the adzuki bean breeding programme through interspecific hybridization. Successful hybrids between adzuki bean and rice bean cannot easily be produced. However, since V. riukiuensis is cross‐compatible with both adzuki bean and rice bean, V. riukiuensis could be useful as a bridge species between adzuki bean and rice bean.
Male Sterility in Barley
Authors: Singh R. B. , Kaul M. L. H.
Published: April 2006

The anther form and development of eight two‐rowed genie male sterile barley mutants are abnormal. The male sterility in each mutant is conditioned by single non‐allelic recessive genes. These mutant genes cause reductions in anther size and lumen diameter. Though in seven mutants, the male meiosis is normal until microspore liberation, the micro‐spores abort in all cases after release from the PMCs. In one mutant, the microspores degenerate at the tetrad stage before release from the PMCs. In four mutants, the tapetal development and disintegration are normal, in four others they are abnormal. Despite these variations, the male sterility in all the eight mutants is complete.
Determination of the Ploidy Level of Pure and Mixed Plant Populations of Sugar Beet (Beta vulgaris L.) by Flow Cytometry
Authors: Akinerdem F.
Published: April 2006

To improve estimates of the true ploidy level of pure diploid triploid, and tetraploid sugar beet (Beta vulgaris L.) plants, and of populations of mixed ploidy, the effect of leaf age/size was evaluated on ploidy determination by flow cytometry. There were significant differences between old and young leaves, with young leaves giving the best estimate of the true ploidy level of the plants. The old leaves seemed to express a high degree of endopolyploidy.
Evaluation of Potato Hybrids Obtained from Tetraploid‐Diploid Crosses I. Parent‐Offspring Relationships
Authors: De Jong H. , Tai G. C. C.
Published: April 2006

A total of 45 tetraploid‐diploid (4x—2x) hybrid progenies were obtained by crossing each of ten diploid parents as males to each of five tetraploid parents. A relatively low degree of determination (R2) of both 4x and 2x parents on the performance of their 4x—2x hybrid progenies was found for all six traits studied. This implies that test crossing and subsequent progeny analysis is necessary before such parents can be used in a breeding program. Since marketable yield was found to have a higher predictability than total yield, it is the preferred yield trait to be measured. Diploids which produce 2n gametes via FDR usually give rise to 4x progenies with a greater amount of heterosis than similar progenies derived from diploids which produce 2n gametes via SDR, although such heterosis is not necessarily expressed in terms of marketable yield.
Screening of Tomato Somaclones for Resistance to Bacterial Canker (Clavibacter michiganensis subsp. michiganensis)
Authors: van den Bulk R. W. , Jansen J. , Lindhout W. H. , Löffler H. J. M.
Published: April 2006

To facilitate testing large numbers of tomato soma‐clones for resistance to bacterial canker, a fast screening procedure was developed. Two inoculation methods were investigated, i.e. excision with an infected scalpel of I) one cotyledon of 2‐week‐old seedlings, and II) the first true leaf of 3‐week‐old seedlings, followed by applying a drop of inoculum on the wound. Inoculation by method II discriminated well between populations of partially resistant and susceptible tomato genotypes. A criterion for the selection of single, putatively resistant plants, based on rating scores of the severity of wilting symptoms, was proposed and tested with plants of a Lycopersicon peruvianum accession with a relatively high level of resistance to bacterial canker. Progenies of 279 somaclones, derived from tissue explants of the susceptible tomato cultivar ‘Moneymaker’, were evaluated for resistance. The presence of somaclonal variation for morphological characters in these populations was previously shown. However, no differences were detected between the somaclone population and controls in either mean susceptibility or distribution of plants over disease severity categories. Moreover, plants with major increases in resistance were not detected. These results suggest that the potential of somaclonal variation as a source of resistance to bacterial canker may be limited.
Genetic Diversity in Tall Fescue Ecotypes from Alabama I. Maturity, Morphological Traits, and Disease Reaction
Authors: van Santen E. , Collins D. J.
Published: April 2006

There is a large hectarage of tall fescue in Alabama. Recognition of the deleterious effects of the endophytic fungus Acremonium coenophialum has resulted in substantial acceptance of new endophyte‐free cultivars. Destruction of old pastures and the concomitant loss of potentially valuable adapted germplasm could be a valid cause for concern. The objectives of this study were to evaluate genetic variation for maturity and plant morphological traits, both among and within tall fescue cv. ‘Kentucky 31’ populations from 18 to 38 year‐old pastures in Alabama. Ten populations of approximately 50 plants each were collected from old Alabama tall fescue pastures. Two pastures were sampled in each of five counties, representing the five major land use areas of the state. In 1990, spaced plants of all populations were evaluated at heading time for maturity, morphological, and disease traits at two locations in central Alabama. Endophyte infection level of the populations ranged from 2 to 100 %. Maturity was highly correlated with tiller length and flag leaf width and was used as a covariate for these traits in the analysis of variance. Leaf rust and net blotch ratings were negatively correlated. Significant variation among populations was observed for maturity and flag leaf dimensions, most variation being due to differences among source counties. Significant variation was observed within all populations for maturity and morphological traits, but only in seven populations for leaf rust. No within‐population variation was detected for net blotch. The average precipitation for the month of May explained 81 % of the variation among populations for maturity. Age of the pasture sampled had a significant effect on tiller diameter (r2= 0.55), and latitude of the pasture sampled was the best individual predictor of leaf width (r2= 0.42). This study reveals that considerable genetic diversity, largely influenced by climatic conditions, exists among ‘Kentucky 31’ tall fescue ecotypes from Alabama.