bluuebunny/crossref_metadata_2025 huggingface dataset:
The Inheritance of Resistance to Septoria Glume Blotch III. The Wild Wheat Species Aegilops Jongissima
Authors: Ecker R. , Cahaner A. , Dinoor A.
Published: April 2006

The genetics of resistance to Septoria glume blotch (caused by the pathogen Septoria nodorum Berk.) in the wild wheat species Ae. longissima was investigated. The resistance was characterized by two parameters measured on detached leaves — lesion size (LS) and length of latent period (LP), and by disease severity (DS) under field conditions. Generations F1, F2 and F3, derived from a cross between two Ae. longissima accessions, were analyzed. The two parameters measured on detached leaves (LS and LP) were highly correlated, while DS was moderately correlated to both LS and LP. The mean LS and the mean LP of F1 generation indicated considerable dominance for resistance in both parameters. The estimates of broad‐sense and narrow‐sense heritability were moderate for LS and LP (0.21—0.55). Narrow‐sense heritability for DS was high (0.77). Estimates of the number of genes controlling each of the parameters (LS, LP, DS) were between 2.5—3.2. It is suggested that the resistance is controlled by three to four quantitative genes with a partial dominance of the alleles for resistance. Indications for genie interaction were found in LS and in LP. A model of inheritance containing complementation between dominant resistance‐alleles is suggested. Highly resistant Ae. longissima accessions are recommended as sources of germplasm for improving the resistance of cultivated wheats to Septoria glume blotch. The possibility of using dominant alleles for resistance in hybrid cultivars is discussed.
Genotype‐Environment Interactions and Stability Analysis for Herbage and Seed Yields of Forage Peas Under Rainfed Conditions
Authors: Abd‐El Moneim A. M. , Cocks P. S. , Mawlawy B.
Published: April 2006

Twenty‐five genotypes of forage peas (Pisum sativum L.) were evaluated under rainfed conditions for two years at four locations in Syria and one in Lebanon. Since local climatic variation is significant, each location in each year was treated as a separate environment, to give ten environments. Genotype‐environment interactions (GXE) were analysed using linear regression techniques.

There was considerable variation in herbage and seed yields within both genotypes and environments. Genotype‐environment interactions were present for both herbage and seed yields; a large proportion of these interactions was accounted for by the linear regression. Although the non‐linear component was also significant, its magnitude was smaller than that of the linear component. The highest and most stable herbage yields were obtained from accessions 46/61, 135/175, 3211/323, 99/103 and 88/335. The highest and most stable seed yields were produced by accessions 4/166, 2428/240, 424/242 and 88/335. Accession 88/335 from Germany, F.R. was the only genotype to combine high herbage and seed yields with wide adaptation and stability and could thus be considered the most widely adapted genotype. Other stable genotypes were identified as suitable for poor environments. Yield of the locally collected genotype, though often high, was found to be unstable. The importance of genotype‐environment interactions in future breeding strategies is discussed.
Computer‐Simulated Evaluation of the Hybrid Weakness Gene System as a Means of Preventing Genetic Contamination of Rice Cultivars
Authors: Yonezawa K. , Sato Y. L. , Nomura T. , Morishima H.
Published: April 2006

Effectivness of the hybrid‐weakness caused by a complementary interaction of two dominant genes Hwc1 and Hwc2 to suppress the spread of the red‐grain gene into ordinary white‐grained rice cultivars was investigated using the Monte Carlo computer simulation method. It was shown that the weakness genes, as far as being capable of reducing the fitness of the carrier by 80 percent or more, work quite effectively to suppress the genetic contamination of white‐grained cultivars due to inflow of pollen from red‐grained cultivars due to inflow of pollen from red‐grain gene once the gene has been incorporated in to the population in the form of red‐grained progeny produced as a result of the imperfect lethality of the initial hybrid between red‐and white‐grained cultivars. The weakness genes have little or no effect cultivars. The weakness genes have little or no effect either, when the contamination is initiated by an inflow of seeds or seedlings from ed‐grained cultivars in these situations, removal (selection)of red grained plants Is the only countermeasure to exterminate the red‐grain gene. The removal of red grained plants need not be intensive if carried out continuously. The spread of the red‐grain gene after initial contamination is suppressed if the red‐grain gene and weakness genes are linked. The suppressing effect of the linkage, however, is not substantial when the outcrossing rate is around or smaller than 0.01 as can be assumed in most rice cultivars.
The Giemsa C‐Banded Karyotype of Canada Wildrye (Elymus canadensis)
Authors: Park C. H. , Kim N. S. , Walton P. D.
Published: April 2006

Karyotype of Canada wildrye (Elymus canadenisis L.) was described using giemsa C‐banding techniques. Most of the chromosomes showed dome banding pattern polymorphism. Small to large terminal and centormere bands were observed in most of the chromosomes. A faint satellite was observed in one chromosome. Tow chromosomes had a large interstitial band near the centromeres in the long arms. The Giemsa C‐banding pattern of E. Canadensis is compared to that of Pseudoroegneria spicata and Critesion boddanii to illustrate species relationship.
Nearly Total Absence of Homoeologous Pairing in a Hybrid between Tetraploid Hordeum chilense and Triticum aestivum
Authors: Pohler W. , Schrader O.
Published: April 2006

A hybrid between an induced tetraploid of Hordeum chilense (2n = 28 = HchHchHchHch) and Triticum aestivum var. ‘Chinese Spring’ (2n = 42 = AABBDD) has been produced to test gene effects of this wild barley on homoeologous pairing in wheat. Cytological investigations in metaphase I have shown that the hybrid, which is perennial like H. chilense but morphologically more similar to the wheat parent, possesses the expected genome composition HchHch ABD and a stable euploid chromosome number of 2n = 35. Pairing among the homologous H. chilense chromosomes was almost complete. The level of non‐homologous chromosome association proved to be lower than the range of pairing known from euhaploids of ‘Chinese Spring’.
A New Embryo Rescue Procedure for Interspecific Hybridization
Authors: Mathias Regine , Espinosa Sonsoles , Röbbelen G.
Published: April 2006

A new technique is presented that allows to overcome very early embryo abortion after interspecific crosses. Embryogenic sectors of young fertilized ovules are cultivated in vitro on a solid/liquid double layer culture medium containing activated charcoal in the solid phase. Hybrid plans are obtained afer transfer the developed for the interspecific cross Cuphea paucipetala greenwooodii×C. laminuligera; but it is most likely also applicable to other combinations, even in different genera.
Somaclonally Induced Earliness in a Brassica juncea Germplasm Accession
Authors: Katiyar R. K. , Chopra V. L.
Published: April 2006

A yellow‐seeded exotic accession of Brassica juncea has shown complete freedom from white rust and powdery mildew and a high degree of resistance to Alternaria black spot under conditions of heavy disease infestation in the field. The germplasm line was, however, too late in flowering and maturity to be useful for either processing directly into a variety or to be involved in a crossing programme for breeding. Somaclonal variation from this accession has provided a highly productive line which retains the resistance to diseases of the parental material.
Continuous Plant Regeneration from Established Embryogenic Cell Suspension Cultures of Italian Ryegrass and Tall Fescue
Authors: Rajoelina Sahondra Radilofe , Alibert Gilbert , Planchon Claude
Published: April 2006

The suitability of different protocols was compared for entire plant regeneration by somatic embryogenesis, of the forage plants Lolium multiflorum Lam. (Italian ryegrass) and Festuca arundinacea Schreb. (tall fescue).

In the first protocol, miniature embryos were used as starting material, while mature seeds were retained in the other two. Whichever the considered protocol, undifferentiated calli were produced on Murashige and Skoog MS medium supplemented with 2,4‐D. The calli were subcultured in the dark on solid MS agar medium, containing 5 mg/1 2,4‐D (protocol 2) or on solid MS medium followed by transfer to a rotated liquid MS medium with 2 mg/1 2,4‐D (protocol 1). In these conditions, induction of somatic embryogenesis occurred, and whole plants were regenerated during a limited lapse of time, upon transfer in the light, to MS medium supplemented with BAP but devoid of 2,4‐D. The simultaneous elimination of 2,4‐D and transfer to light appeared essential for full regeneration of the plants. Using this characteristic, an additional step was added to a new protocol (protocol 3) in which microcalli, cultured on liquid MS medium containing 5 mg/1 2,4‐D, were transferred to the same medium with 2 mg/1 2,4‐D, in the dark. In these conditions, the suspensions kept their embryogenic potential for months.

In all cases, plantlets were successfully transferred into the soil. An evaluation of the somaclonal variation potential of the plants issued from each protocol is now underway.
Die Nutzung der Antherenkulturmethode im Zuchtprozeß von Winterweizen
Authors: Mülier G. , Böhme T. , Borschel H. , Vahl U. , Wiberg A.
Published: April 2006

Anther culture in the breeding process of winter wheat. III. Ability of winter wheat F1 populations with the two heterozygous 1AL–IAS/1AL–IRS and 1BL–1BS/1BL–IRS chromosome pairs

Application of anther culture to four F1 hybrids between the IBL–IRS (‘Amigo’) and several 1BL–IRS wheat‐rye translocation forms yielded 129 green pollen plants in an average embryo induction frequency of 17.6 %. A total of 2632 anthers was inoculated. 25 % and 42 % of the regenerated plants were haploid and spontaneously doubled haploid, and 33 % had abnormal chromosomal structure.

After chromosome doubling treatment 87% of all pollen plants set seeds. By means of multiple peroxidases and Giemsa C‐banding patterns, the anther culture progeny could be further classified into 16 plants without the short arm of IR‐chromosome of rye, 21 IAL–IRS and 50 1BL–IRS translocation lines and into 16 IAL–IRS, IBL–IRS double translocation lines according to the four possible characteristic types of F2 gametes of the tested F1 hybrids. Advantages of the haploid technique for the selection of desirable traits and the meaning of the IRS genes in wheat are discussed.
The Use of Potato Haploids to Put 2x Wild Species Germplasm into a Usable Form
Authors: Janskv S. H. , Yerk G. L. , Peloquin S. J.
Published: April 2006

An effective method of incorporating germplasm of wild 2x Solanum species into the cultivated potato is through hybridization with haploids of 4x S. tuberosum Group Tuberosum. This procedure provides for the introduction of desirable traits and genetic diversity from wild species into potato. Haploid and wild species genotypes can be evaluated for parental value based on the presence of good tuberization, desirable traits, fertility, and 2n gametes in their hybrid progeny. Haploid‐wild species hybrids may be intercrossed and evaluated at the 2x level to take advantage of diploid genetic ratios. Selected 2x genotypes may then be brought to the 4x level through sexual polyploidization with 2n gametes.
Studies on Low Crossabilities Encountered with the Hordeum bulbosum Method for Haploid Production of Barley, Hordeum vulgare L.
Authors: Devaux P. , Adamski T. , Surma M.
Published: April 2006

Crosses were made between four spring barley (Hordeum vulgare L.) cultivars and five F1, hybrids with one genotype of Hordeum bulbosum L. in two locations to investigate further previous low crossabilities which had been found in the barley cultivar ‘Apex’ with H. bulbosum.

Data at all the main steps of the H. bulbosum technique were recorded and statistically analyzed. Significant differences between barley genotypes were demonstrated for all characters. It was confirmed that ‘Apex’ has poor crossability with H. bulbosum. Out of the three F1 hybrids having ‘Apex’ as one parent, two exhibited low crossability similarly to ‘Apex’ but one showed significantly higher seed setting than ‘Apex’.

The effect of the location was only significant on seed setting, while genotype X location interactions were significant on seed setting, seed quality and rate of haploid plants in relation 10 florets pollinated. Another problem which has influenced the success rate of the H. bulbosum method was found in the cultivar ‘Havilla’. Although seed setting and seed quality were high for this cultivar, embryo differentiation was low. However, this latter problem was found to influence less the overall success rate than poor crossability.

Mahalanobis's distances were calculated and the dendrite of the shortest distances between barley genotypes was plotted.
Association of Eyespot Resistance in Wheat cv. ‘Cappelle‐Desprez’ with Endopeptidase Profile
Authors: Koebner R. M. D. , Martin P. K.
Published: April 2006

To test for the association of the eyespot of wheat cv. ‘Cappelle‐Desprez’ with the structural gene encoding the isozyme Ep‐A1, F3, families from the cross ‘Cappelle‐Desprez’ (resistant) X ‘Chinese Spring’ (susceptible) were selected on the basis of endopeptidase phenotype. Analysis of eyespot reaction showed that Ep‐Alb homozygotes were associated with a higher level of resistance than Ep‐Al a homozygotes. Thus selection of the Ep‐Alb allelc should assure concurrent selection of at least a part of the eyespot resistance of ‘Cappelle‐Desprez’.
Variability of the Content of Soluble Non‐Digestible Polysaccharides in Rye Inbred Lines
Authors: Madej L. , Raczynska‐Bojanowska K. , Rybka K.
Published: April 2006

The content of soluble non‐digestible, non‐starch polysaccharides (SNDP) in grain of about 700 inbred lines of rye varied during three seasons (1985–1987) from 35 to 75 mg/g with the highest frequency between 55 and 75 mg/g. The SNDP level in popular Polish open pollinated cultivars was never below 60 mg/g.

The results of reciprocal crosses proved lack of xenia effect on the SNDP content.

The level of SNDP compounds was not correlated with either protein or thousand kernel weight.

In spite of large environmental effect of SNDP and protein contents the coefficients of variation of these characters in S3 sublines in each environment were below 7 % and the heritability in broad sense amounted up to 0.73 for SNDP and 0.61 for protein. A few lines have been selected with low SNDP content transferred to their progenies. In some of them protein content was as high as 18%; these might be good donors of high nutritive value.
A Selection Index to Cope with Genotype‐Environment Interaction with an Application to Wheat Breeding
Authors: Louw J. H.
Published: April 2006

The objective of this study was to develop a genetic selection index for the combination of quantitative observations repeated in different environments when there may be genotype‐environment interactions and heterogeneity of the variance. A distinction is made between the index for local ranking of strains for each environment on its own and the index for a joint ranking which predicts mean genotypic value averaged over all environments. The resulting index was applied to field trial observations on the yield of wheat at two locations, involving 276 newly developed strains in six trial groups of equal size, in order to study the efficiency of the index and the sampling variance of index weights. The index for local ranking of strains was found to be consistently more efficient than ranking without the index, though only marginally so in trials with low coefficients of error variation. Limitations on general use of the index, as related to trial size and the standard errors of index weights, are discussed.
Applications of Genie Male Sterility in Plant Breeding
Authors: Rao M. Krishna , Devi K. Uma , Arundhati A.
Published: April 2006

The possible applications of genie male sterility (GMS) in plant breeding arc reviewed and discussed. The basic contribution of GMS is that it provides a means of genetic emasculation which can be applied for the massive production of hybrids. There are two main fields of application: (1) the production of hybrid varieties and (2) inter‐ and intraspecific hybridization and back‐crossing programmes for the introduction of genetic variation into crop varieties. Several schemes have been proposed for using GMS in hybrid breeding in different crops. These are discussed under four headings: genetic methods, cy‐togenetic methods, temporary restoration of fertility and manual pollination. The application of GMS in hybridization intended for the introduction of alien genes is discussed as well as factors affecting the pollination of genie male steriles.
Methods of Visually Rating Maturity in Tetraploid Dactylis L.
Authors: Van Santen Edzard , Casler M. D.
Published: April 2006

Plant maturity descriptors are important for many forage breeding decisions and in forage production research. The objectives of this study were to evaluate the effects of genotypes, maturity rating scale, maturity rating unit, and observer on visual evaluations of maturity in Dactylis glomerata. Tetraploid clonal material was planted at three locations in Wisconsin in August of 1986. All plants were rated for maturity in early June 1987; locations were rated within 3 days of each other. For most family‐location combinations, parents were more advanced in maturity than offspring family means. Family maturity could not be predicted from mean parent maturity scores. Genotype × location was the only significant interaction. On the average, the single digit rating scale led to an earlier assigned maturity value than the two‐digit scale. The discrepancy between the rating scales was dependent on location. High phenotypic correlations between rating units and between rating scales suggested that ratings can be done on a whole‐plant basis using either scale. However, if maturity is used as a covariate for another trait, a two‐digit scale is preferred.
Investigations on the Anther Culturability of Four German Spring Wheat Cultivars and the Influence of Light on Regeneration of Green vs. Albino Plants
Authors: Ziegler G. , Dressler K. , Hess D.
Published: April 2006

In anther culture experiments with four German spring wheat cultivars (‘Turbo’, ‘Kadett’, ‘Planet’ and ‘Nandu’), ‘Nandu’ showed the best results. The rate of responding anthers with ‘Nandu’ was 0.8 % on medium N6 and 3.7% on potato‐2. This was similar to the Chinese cultivar ‘Orofen’. Higher yields of embryoids could be obtained with medium potato‐2 than with N6.

Experiments with medium potato‐2 showed that anther response, production of embryos and regeneration increased with decreasing agarose concentration.

Regeneration of green plantlets was improved by differentiation in the dark whereas differentiation under light yielded more than 90 % albino plants.
Effect of Lr34 Resistance on Leaf Rust Development, Grain Yield and Baking Quality in Wheat
Authors: Drijepondt S. C. , Pretorius Z. A. , van Lill D. , Rijkenberg F. H. J.
Published: April 2006

The protection provided by the leaf rust resistance gene Lr34 against Puccinia recondita f. sp. tritici was studied in the field over two seasons. In leaf‐rust inoculated and fungicide‐sprayed control plots, yield of RL6058, the ‘Thatcher’ backcross line with Lr34, was compared to that of the susceptible cultivar ‘Thatcher’. Leaf rust severity remained low on RL6058 in both seasons, but was high on ‘Thatcher’. The latent period of wheat leaf rust isolate 3SA132 in flag leaves of RL6058 was 256 h longer than in ‘Thatcher’. The uredinium density on ‘Thatcher’ was 14.4/cm2, compared to 3.7/cm2 flag leaf surface on RL6058. Leaf rust infection of ‘Thatcher’ reduced the total grain yield per plot by 25.4% and 1,000 kernel mass by 15.6%. Leaf rust caused little or no damage on RL6058 and rusted plots outyielded the control plots by 0.3 %. Seed weight of RL6058 was reduced by 0.7%. Compared to previous greenhouse studies, the adult‐plant resistance conferred by Lr34 is more clearly expressed in the field. Evaluation of milling and baking quality characteristics revealed that compared to ‘Thatcher’, RL6058 had a higher flour protein content, but that its milling, dough development and baking properties were inferior.
The Location of Sources of Field Resistance to Bremia lactucae in Wild Lactuca Species
Authors: Lebeda A.
Published: April 2006

Thirty‐one accessions of four Lactuca species (L. serriola, L. saligna, L. aculeata, L. squarrosa) and one L. serriola×L. sativa hybrid were screened for field resistance to Bremia lactucae. In the L. serriola group, significant differences in the level of field resistance were distinguished. The accessions PI 281876 and PI 253467 were free of infection. Moreover, all L. saligna accessions tested were totally free from disease during three‐year‐investigation.
Chromosomal Location of a Catalase Gene in Wheat Using Rye‐Wheat‐Additions
Authors: Thiele V. , Seidel A.
Published: April 2006

Rey‐cytoplasmic rye‐wheat‐additioons were analysed for catalase structural genes using polyacrylamide gel electrophoresis. A structural gene of wheat was found to be located on chromosome 4b and on telocentric 4bL, respectively.
Production of Primary Triticale from Calluses of Immature Abnormal Hybrid Embryos between Triticum durum and Secale cereale
Authors: Shao Z. Z. , Taira T.
Published: April 2006

Plant regeneration was attempted in callus induced from the immature abnormal hybrid embryos between T. durum and S. cereale, using 4‐Huorophenoxyacetic acid as a growth regulator. In particular, the relationship of numerical variation in chromosomes between the callus tissues and the regenerated plants was investigated. Cytological observation revealed that there was no distinctive numerical difference between the shoot‐forming (SF) and the non‐shoot‐forming calluses and also between the SF calluses and the regenerated plants. The root‐tips of regenerated plants consisted of cells having various chromosome numbers, including the expected 2 n = 3 ×= 21 (genomes, ABR) of which the frequency was 69.8 %. The regenerated plants showed partial fertility, notwithstanding that the hybrid plants were expected to be sterile. Since the frequency of abnormal embryos was about 90 % in this cross, the utilization of abnormal embryos was demonstrated by use of callus culture.
Screening of Rice Varieties for Endosperm Storage Proteins
Authors: Bhowmik A. , Omura T. , Kumamaru T.
Published: April 2006

A total of 118 rice varieties/lines (Oryza sativa L.) from Bangladesh were analyzed for endosperm storage proteins on a single seed basis. The screening was done by observing the profiles of sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS‐PAGE) with standard japonica variety ‘Kinmaze’. Six groups were classified on the basis of the poly‐peptide banding patterns. Two‐dimensional gel electrophoresis was performed to ensure the SDS‐PAGE results in selected varieties. The analysis of extracted protein fractions revealed that one variety had low prolamin and one variety had high glutelin content.
Path‐Coefficient Analysis of Seed Yield Components in Euphorbia lathyris L.
Authors: Hondelmann W. , Strauss D. D.
Published: April 2006

The interrelationships of seed yield components in Euphorbia lathyris L. have been studied by means of path‐coefficient analysis. Two of seven components, ‘Number of flowers of primary inflorescence’ and ‘Number of flowers of secondary inflorescences’ proved to be of major importance through direct effects on ‘Total number of fruits’ as indicator of seed yield. Indirect effects generally arc being canalized via the same variables. Selection for seed yield is made possible through the relation between ‘Number of secondary branches’ and ‘Number of flowers of secondary inflorescences’.
Study on the Inheritance and Relationship of Some Morphological and Fertility Characters in Faba Bean (Vicia faba L.)
Authors: Duc G. , Berthaut N. , Pellletier R. , Carteron A.
Published: April 2006

Inheritance of several morphological and fertility characters was studied in F2 generation of two sets of diallel cross, using Griffing's analysis of variance. A paramount importance of general combining ability (GCA) over specific combining ability was measured for most studied characteristics. Correlations among GCA values for seed yield, morphological and fertility characters do not give a clear definition of the plant ideotype. “Terminal inflorescence” character appeared to reduce the seed per ovule ratio. Higher additive component was found for the ovule per pod than for seed per pod characters.
Influence of Acute and Fractionated X‐Ray Doses on Shoot Production of in Vitro Derived Explants of Gerbera jamesonii H. Bolus
Authors: Walther F. , Sauer Annemarie
Published: April 2006

In vitro mutation induction experiments will become economically relevant only if the genetic variation can be highly increased by this procedure. For that purpose the utilization of as high X‐ray doses as possible are considered an important prerequisite. It was the objective to investigate the effect of split versus acute X‐ray doses on in vitro derived micro shoots of Gebera jamesonii used as references system for plant species that can be propagated in vitro by axillary shoots. Splitting of doses between 10 Gy and 50 Gy into 2 or 3 fractions separated by periods of 4th each for recovery led to considerably rising shoot production. The recovery from damage, represented by accumulating the number of shoots developed during 16 weeks at 4 subsequent dates pf cutoff post‐treatment, by propagation profiles, and by calculation of the factor of recovery, resulted in the application of very high X‐ray doses only usable by means of multiple dose fraction procedures.
Greenhouse Method for Testing of Resistance of Young Brassica Plants to Alternaria brassicae
Authors: Gröntoft M. , O'Connor D.
Published: April 2006

Small differences in attack of Alternaria brassicae on Brassica species are difficult to detect in the field. Therefore, a more detailed method was developed in the greenhouse. Small agar discs with Alternaria brassicae were placed with the infected sides against the upper side of the 2nd leaf, over a 4 mm hole. The necrotic lesions on the leaves were measured 7 days after inoculation. The test results indicate that differences in resistance do exist. It is, however, doubtful if the resistance is great enough to be used in a plant breeding programme.
Selection in Early Generations of Dried Peas, Pisurm sativum L.
Authors: Stelling D. , Ebmeyer E.
Published: April 2006

Seed production in peas is limited by early and severe lodging and by a low multiplication rate and pea breeders have tried to overcome such disadvantages by growing plants in early generations widely‐spaced against wire netting. Progenies of four pea crosses were each tested over a period of tour years to investigate whether single plant selection for quantitative characters, in particular grain yield, is efficient in such circumstances in the Is generation. Efficiency of selection was also studied for yield and yield related characters in the F3 based on f2 derived single plant progenies grown in unreplicated microplots.

Early yield selection in the F2 as well as in the F3 proved to be of poor efficiency. Heritability values of all recorded traits were only slightly higher in the F3 than in the F2. Efficiency of yield selection could not be increased significantly in these early generations by indirect selection, either for single traits or for index traits.

Possible reasons are discussed for the low efficiency of direct and indirect selection for grain yield in early generations and proposals are made for its improvement and for alternative selection strategies.
Flag Leaf Variation and the Analysis of Diversity in Durum Wheat
Authors: Spagnoletti Zeuli P. L. , Qualset C. O.
Published: April 2006

Flag leaf in wheat (Triticum spp.) is a major source of photosynthate for the developing grain and its size contributes to interplant competition. Flag leaf length, width, and area in a sample of 778 entries of durum wheat (T. turgidum L. durum group) germplasm obtained from the U.S. National Small Grains Collection showed considerable phenotypic variation. Correlations between flag leaf and eight spike quantitative characters showed significant values greater than 0.30 for kernel weight per spike with all three flag leaf measurements and for awn length with flag leaf length and area. Larger flag leaf area appeared to be associated with accessions having a history of some deliberate plant breeding for high grain yield. A multivariate approach was used to assess how discrimination among 26 countries of origin obtained with spike characters in a previous study was affected by reducing the sample size from about 3,000 to 735 and by the addition of flag leaf measurements to the analysis. The reduced sample size had little impact on the results of the previous analysis on the whole collection of about 3,000 entries. The addition of flag leaf characters to the analysis caused a rearrangement in the clusters of countries, mostly from Asia, where less germplasm modified by plant breeding was included in the collection. Five clusters were identified: (1) 11 Mediterranean basin countries, (2) USA, UdSSR, and Yugoslavia, (3) four Near East Countries and Bulgaria, (4) three Middle East countries and Greece, India and Ethiopia, and (5) Afghanistan. Phenotypic differentiation of durum wheat, and probably many other crops, on a geographic basis is more pronounced in areas where plant breeding has had little impact.
The Use of Stomatal Chloroplast Number for Rapid Determination of Ploidy Level in Maize
Authors: Ho I. , Wan Y. , Widholm J. M. , Rayburn A. L.
Published: April 2006

The usefulness of using the chloroplast number in epidermal guard cells as an indirect ploidy indicator was evaluated on seed‐grown and tissue culture‐derived maize plants. For seed‐grown plants, two maize genotypes (B89 and R75) which had both diploid and tetraploid seeds available were used as experimental materials. The ploidy levels of seed‐grown plants were confirmed by flow cytometric analysis of nuclear suspensions from these plants. For regenerated plants, haploid and diploid levels were examined and the ploidy levels of these plants were determined by chromosome counts of cells from root tips. A positive relationship between the chloroplast number and ploidy level was observed for both seed‐grown and regenerated plants. The stomatal guard cells of tetraploid plants had nearly double the number of chloroplasts as the diploid plants. Similar results were found from the regenerated plants. The differences in the mean chloroplast number between diploid and tetraploid seed‐grown plants and between haploid and diploid regenerated plants were highly significant. The results of this study demonstrate that counting chloroplasts in guard cells can be an efficient means of screening a large number of plants for ploidy levels. In addition, this study suggests the possibilities of using this method for detecting contaminated seed lots by different ploidy seed and for distinguishing plants of different genotypes.
Rust Resistance and its Stability in Lines of Varying Productivity in Groundnut (Arachis hypogaea L.)
Authors: Gowda M. V. C. , Akunachalam V. , Bandyopadhyay A.
Published: April 2006

Twenty six lines of groundnut (Arachis hypogaea L.) of varying productivity were tested for yield under four treatments involving fungicidal control of rust and leafspots. Disease severity was measured at two stages of growth, namely 70 days (stage 1) and 90 days after sowing (stage 2). Instead of pod yield, a score (based on an Isd test and grouping over pod yield, shelling %, 100‐kernel weight and % residual green leaf area at stage 2) was used to define performance status of the lines. A study of various character combinations revealed the importance of % residual green leaf area at both stages 1 and 2 in predicting the relative yield performance of lines. This result was obtained by comparing the % agreement of the status of lines given by a particular character set with performance status and was confirmed by a multiple regression analysis of pod yield on all other traits. Seven lines and three progenitor parents showed stability of performance with respect to rust resistance. They included lines derived from crosses between the national check, ‘Robut 33—1’, as one parent and either a rust resistant genotype, NC Ac 17090 or an early Russian accession of (Spanish type) ‘Chico’, as the other. It was suggested that breeding programmes should take into account performance status based on yield and disease severity instead of pod yield alone.
Selection in Early Generations of Dried Peas, Pisum sativum L. III. Plot Size and Plot Type
Authors: Stelling D. , Ismail M. H. , Ebmeyer E. , Fraukn M. , Robbelen G.
Published: April 2006

Investigations were carried out to study the effect of different plot sizes and plot types on the performance of peas and to determine plot size and plot type combinations suitable for the reliable evaluation of varietal yield performance realized in commercial stands of pea crops. Four pea varieties were tested in 1981 and 1982 in combinations of plot sizes ranging from 0.25 m2 to 19.50 in2 with plot types either unbordered, bordered with faba beans, surrounded with perforated plastic foil or only central sections of plots harvested (net plots).

With decreasing plot size the performance mean as well as the error variance of grain yield and thousand grain weight increased disproportionately. Thus, changes in grain yield were much higher than those for thousand grain weight. The four varieties tested reacted differently to changing plot sizes and as a result, highly significant variety × plot size interactions were found. Although overestimation of grain yield in small plots could be strongly reduced by bordering the plots with faba beans or surrounding them with plastic foil, their suitibility for yield testing was limited by highly significant variety × plot type interactions. Compared to the largest net plot (15 m2) reliable results were still obtained with plot sizes larger than 6.5 m2, no matter whether edge effects were eliminated or not. If only a small quantity of seed is available, plots may be reduced even to 1.00 m2, if surrounded by plastic foil.

The results presented in peas were compared to those in other crops and discussed concerning their relevance for variety testing as well as for selection of grain yield in early generations.
Studies on the Influence of Photoperiod and Temperature on Floral Traits in Buckwheat (Fagopyrum esculentum Moench) under Controlled Stress Conditions
Authors: Lachmann S. , Adachi T.
Published: April 2006

Floral traits of three Japanese and one European buckwheat varieties were studied in a phytotron under three photoperiods (short‐day 10/14 h, long‐day 14/10 h, extreme long‐day 18/6 h) and two thermoperiods (25/20, and 15 °C constant temperature). The Japanese varieties showed a strong delay in flowering under prolonged day length, whereas one European variety reacted almost day‐neutral. Also affected by the photoperiod were the number of flower clusters as well as their sizes. A constant low temperature of 15 °C led to a strong delay in flowering under short‐ and long‐day in all the varieties tested. In particular, the Japanese varieties were sensitive to temperature, developing more flower clusters under high temperature. Furthermore the experiments revealed complex genotype/pliotopenod/thermoperiod interactions. The study, conducted to investigate the causes of low seed‐set observed in buckwheat, offered some suggestions for new breeding strategies. Insensitive genotypes, showing less sensitivity to photoperiod as well as to thermoperiod, should be included in further buckwheat improvement.
The Use of Monosomic Rye Addition Lines for Transferring Rye Chromatin into Bread Wheat
Authors: Ren Z. L. , Lelley T. , Röbbelen G.
Published: April 2006

Hybrid plants with 21 pairs of wheat chromosomes and with a haploid rye genome were produced by backcrossing a primary octoploid triticale with its parental hexaploid wheat. Upon a second backcrossing or selfing, the rye chromosomes were eliminated rapidly. Added rye chromosomes, in varying numbers, affected the transmission rate of wheat chromosomes significantly. Loss of wheat chromosomes ranging from 0.06 to 0.35 per plant in different populations was observed. In these plants a remarkably high incidence of wheat/rye and rye/rye translocations occurred. Translocations were identified by using the C‐banding technique. Among 837 analyzed plants 64 wheat/rye and 256 rye/rye translocations were identified. In different generations of backcrossing or selfing the frequency of wheat/rye translocations varied between 4.23 % and 14.67 %. All 14 rye chromosome arms were involved in translocations but with different frequencies. BC1F3 plants with homozygous wheat/rye translocations were isolated The results indicate that monosomic wheat/rye addition lines may be directly used as an effective means to transfer genetic material from rye into bread wheat.
The Use of Monosomic Rye Addition Lines for Transferring Rye Chromatin into Bread Wheat
Authors: Ren Z. L. , Lelley T. , Röbbelen G.
Published: April 2006

The successful transfer of mildew resistance, plant height suppression, leaf colour and several quantitative traits effecting yield from rye into wheat is demonstrated. Plants exhibiting these characters were derived from genotypes which contained a homozygous wheat genome (21”) and different number of additional rye chromosomes in the monosomic condition. Using the C‐banding technique wheat/rye translocation could not be detected in these plants, indicating that the size of the transferred segment must have been below the resolution power of this technique. The results suggest that in wheat plants with additional rye chromosomes in monosomic condition small segments of rye chromosomes with valuable genes are being transferred into wheat by translocation, most probably, between homoeologous wheat and rye chromosomes. The technique described in this paper appears to be a simple way of using rye chromatin in wheat improvement.
Responses to Selection for Root Dimension in a South European Variety of Perennial Ryegrass)*
Authors: Veronesi F.
Published: April 2006

The objective of the study was to determine the effect of selection for large root dimension on root and shoot characteristics of an Italian variety of Lolium perenne L. (cv. ‘Vejo’). Two cycles of recurrent restricted phenotypic selection (RRPS) were carried out in 1983 and 1984 at Perugia (Italy). In each cycle, 20 out of 1,500 plants were selected and intercrossed under isolation. In 1985, 120 plants from‘Vejo selected’ and an equal number of plants from‘Vejo’ initial seed‐lot were grown hydroponically for 92 days; at the end of the experiment, the plants were measured for their number of leaves and stems, leaf length, length of the longest root, root volume and shoot and root dry weight.

Sufficient genetic variability existed among plants of cv. ‘Vejo’ to allow highly significant responses to selection for root dimension (+25 % in root length, +39 % in root volume, + 67 % in root dry weight and +31 % in root: shoot dry weight ratio). Furthermore, two cycles of RRPS for root dimension did not show negative responses of the above‐ground parts of the plant.
Effect of Cultivar, Incubation Temperature, and Stage of Microspore Development on Anther Culture in Wheat and Triticale
Authors: Hassawi Dhia S. , Liang G. H.
Published: April 2006

Effects of incubation temperature and developmental stage of microspores on polyhaploid production in three wheat cultivars‘Pavon 76′, ‘Kitt’, and ‘Chris’ and one triticale cultivar, ‘T81′, were studied using a one‐step medium. Calli failing to differentiate on the one‐step medium were placed on a medium containing 1 mg/l indole‐3‐acctic acid (IAA) and 2 mg/1 6‐furfurylaminopunne (KIN). Anthers containing either early‐ or late‐uninucleate microspores were incubated in dark at 26, 28 or 32°C lor 3 days prior to transfer to 26°C. Averaged over temperatures and microspore stages, frequency of calli and green plantlets were 8.9 % and 3.4 %, respectively, for wheat cultivar‘Pavon 76′, 8.4 % and 1.6 % for cultivar ‘Kitt’, 4.5 % and 0.25 % for cultivar ‘Chris’, and 2.9 % and 0.12 % for the triticale cultivar‘T81′. However, cultivar‐by‐developmental‐stage interaction was significant for frequency of callus induction. Temperature had no significant effects on callus induction and plantlet regeneration. Anthers containing early‐unmucleate microspores produced no polyhaploids.
Genetic Analysis of Resistance to Phytophthora Root Rot in Tomato (Lycopersicon esculentum Mill.)
Authors: Kozik E. , Foolad M. R. , Jones R. A.
Published: April 2006

The resistant accession, LA1312, and the susceptible cultivar ‘Peto 343′, were crossed to develop F1, F2 and BC1 populations for genetic analysis of resistance in tomatoes to Phytophthora parasitica Dastur, the causal agent of Phytophthora root rot. There was no maternal effect on resistance. Generation means analysis indicated that tolerance to Phytophthora root rot was under genetic control with both simple (additive and dominance) and digenic interaction (additive × additive and additive × dominance) effects contributing to the total genetic variation among generation means. Weighted least square regression analysis indicated that the majority (ca. 96 %) of the genetic variation could be explained by simple additive effects alone. Narrow sense heritability was estimated as 0.22. Based on effective factor formulae, at least five effective factors controlled the resistance. Implications for breeding procedures are discussed.
Transformation of Medicago sativa L. Using a Ti Plasmid Derived Vector
Authors: Pezzotti M. , Pupilli F. , Damiani F. , Arcioni S.
Published: April 2006

A cultivar of Medicago sativa was transformed with Agrobacterium tumefaciens strain At81 binary‐vector carrying the plasmid pKan3A, with the neomycin phosphotransferase gene under the control of the mannopine biosynthesis promoter. Stem segments were infected with the bacterium and kanamycin resistant calli were obtained; plant regeneration via somatic embryogenesis and polyembryogenesis was achieved only in media devoid of the antibiotic. Genetic transformation was confirmed by the presence of the structural gene through DNA‐DNA hybridization and the enzymatic assay showed its functional expression. Mesophyll protoplasts, leaf calli and S1 progeny of transformed plants grew in the presence of kanamycin (100 μgml‐1). Results are discussed in relation to the use of kanamycin‐resistant plants in somatic hybridization in the genus Medicago.
Genetical Studies of Gibberellic Acid Insensitivity in Rye (Secale cereale L.)
Authors: Börner A.
Published: April 2006

Genetic analysis of three semi‐dwarf genotypes of rye (Secale cereale L.)—‘Moskowskij Karlik’, ‘Gülzow kurz’ and ‘R 18’, which were shown to be insensitive to applied gibberellic acid (GA3), has been carried out by using a seedling test. It could be demonstrated that all of the three genotypes are carrying recessive alleles for GA‐insensitivity. Whereas the alleles of ‘Moskowskij Karlik’ and ‘R 18’ seem to have the same locus on chromosome 5R, the GA‐insensitivity of ‘Gülzow kurz’ is governed by a different gene, most probably located on chromosome 7R. The relationship between the genes (alleles) for GA‐insensitivity and semi‐dwarfness, including the symbolization of the Gai‐genes as well as their utilization in rye breeding is discussed.
Development Traits Affecting Time to Low Ear Moisture in Maize
Authors: Newton S. D. , Eagles H. A.
Published: April 2006

A diallel cross of six inbred lines of maize (Zea mays L.) from the Corn Belt of the USA and one inbred line (NZ1A) with characteristics of maize from the highlands of Mexico was grown in a cool, temperate environment. The objective was to investigate interrelationships and combining abilities of plant development traits likely to influence the time required to reach low ear moistures in the field. The traits were days to silking, days to physiological maturity, ear moisture at physiological maturity, grain filling duration and ear drying rate after physiological maturity. Grain yield and grain moisture at harvest were also considered.

Differences among the hybrids of this diallel cross for ear and grain moisture at the usual harvest time were largely determined by differences in ear drying rate after physiological maturity, and not by differences in days to silking, days to physiological maturity, or in ear moisture at physiological maturity. General combining ability (GCA) effects were much larger than specific combining ability (SCA) effects for all traits. NZ1A had positive GCA effects for grain filling duration and negative GCA effects for ear moisture at physiological maturity which were outside the range of the Corn Belt lines suggesting that this line, or similar Mexican germplasm, could be useful for developing hybrids with high grain yields and low ear moistures at harvest in cool, temperate environments.
The Effect of Chromosome 1B/1R Translocation on the Yield Potential of Certain Spring Wheats (Triticum aestivum L.)
Authors: Villareal R. L. , Rajaram S. , Mujeeb‐Kazi A. , Del Toro E.
Published: April 2006

Nearly 50 percent of the 1988 advanced breeding lines of the CIMMYT bread wheat breeding program possess the 1B/1R homozygous translocation. Hence, a trial was conducted to estimate the effect of 1B/1R chromosome translocation on the yield potential of some of our high‐yielding spring wheats, where non‐limiting levels of fertility, moisture, preventive pest and disease programs were used. In conclusing the 1B/1R lines seemed to have increased their above‐ground biomass yield, number of spikes per meter2, 1000‐grain weight and test weight. They also exhibited a slight advantage over the 1B homozygous lines on grain yield. The observed difference, however, was non‐significant, as was the plant height difference observed among the two groups. Varietal comparisons indicated that the 1B/1R group headed later than the 1B group.
Breeding of Polyploid Asparagus (Asparagus officinalis L.)
Authors: Skiebe K. , Stein M. , Gottwald J. , Wolterstorff B.
Published: April 2006

Asparagus is especially suitable for polyploidy breeding. The aim is to develop clone‐based hybrid varieties, in particular male 4 × varieties. For this purpose, genetically divergent diploid idiotypes*) are subjected to mitotic or meiotic polyploidization. In developing hybrid partners, special attention is paid to resistance in addition to yield and quality characters. Early diagnoses are applied in selection so as to shorten breeding times. Somaclonal variations may occur relatively often on in vitro propagation; these need to be eliminated. Triplex and quadruplex type males are suitable for paternal hybrid partners. Strong inbreeding depressions need to be avoided in their production.