bluuebunny/crossref_metadata_2025 huggingface dataset:
Agronomic Performance of Wheat Doubled‐Haploid Lines Derived from Cultivars by Anther Culture
Authors: Baenziger P. S. , Wesenberg D. M. , Smail V. M. , Alexander W. L. , Schaeffer G. W.
Published: April 2006

To determine the level of gametoclonal variation among doubled‐haploid lines (DHLs) of Triticum aestivum L. developed using anther culture techniques and its effect on agronomic performance, 70 anther culture‐derived DHLs of ‘Kitt’ were compared for 7 agronomic traits to 50 single‐seed descent‐derived lines (SSDLs) of ‘Kitt’ and to the cultivar ‘Kitt’. In a second experiment, 26 DHLs of ‘Chris’ were compared for 7 agronomic traits to 29 SSDLs of ‘Chris’ and to the cultivar ‘Chris’. Each experiment was grown as a randomized complete block design with three replications in three environments. For ‘Kitt’, the DHLs averaged significantly lower grain yields than the comparable SSDLs. For ‘Chris’, the DHLs averaged lower, but not significantly lower, grain yield than the SSDLs. In both ‘Kitt’ and ‘Chris’, the genetic component of variance for yield of the DHLs was significantly larger than that of the SSDLs indicating the presence of gametoclonal variation. The lower average grain yield of the DHLs was explained by a larger group of low‐yielding DHLs than was present in the SSDLs. Six ‘Kitt’ DHLs and 3 ‘Chris’ DHLs were lower yielding than the lowest yielding SSDL, respectively. Elite DHLs and SSDLs were similar for mean grain yield performance. Though the DHLs and SSDLs were significantly different for some yield components, the affected yield component changed with the cultivar and there was no consistent effect. Significant genotype × environment interactions were detected for some traits which were caused by changes in the magnitude of differences, rather than reversals in ranking, indicating that low yielding DHLs could be culled on the basis of visual selection or single‐environment testing. Hence, gametoclonal variation was induced by the anther culture techniques used in this study, tended to be deleterious for grain yield, and was sensitive to the growing environment. However, as the DHLs and SSDLs had similar expected population means based upon expected gains from selection, this gametoclonal variation should not be a major hindrance to wheat breeding.
The Effect of Carbohydrate Composition and Concentration on Anther Culture Response in Barley (Hordeum vulgare L.)
Authors: Finnie S. J. , Powll W. , Dyer A. F.
Published: April 2006

Culture medium composition is critical for the successful induction of microspore division in vitro. The present experiments have focused on a relatively neglected area of cell and tissue culture research, namely the carbohydrate component used in the medium. Three spring barley genotypes were cultured on a medium which was modified by replacing sucrose with the following carbohydrates (6 % w/v): maltose, fructose, malt extract, galactose and a glucose (3 % w/v)/fructose (3 % w/v) mixture. Both maltose and malt extract were superior to sucrose in their capacity to induce green plantlet differentiation from microspores. The concentrations of both sucrose and maltose were also varied. Overall the response of anthers on maltose based media was higher than on sucrose based media. Furthermore, a concentration of maltose m the range 6—12 % w/v produced a higher frequency of green plants than a low concentration (1—3 % w/v). The effect of maltose based media on germplasm of direct relevance to barley breeders was also tested. The cultivar ‘Blenheim’ was shown to be very responsive and this genetic factor was transmitted to the F1 hybrid. The frequency of haploid to diploid regenerants was not consistent over genotypes, but in general there were more haploid than diploid regenerants. The implications of these results for barley breeding are discussed.
Efficient Yield of Embryoids by Culture of Isolated Microspores of Different Brassicaceae Species
Authors: Lighter R.
Published: April 2006

Microspore culture of rapeseed (Brassica napus) is well established in practical plant breeding as a potent method to produce homozygous plants. Except for B. carinata the method has not yet been applied to other Brassicaceae species. The present study describes successful microspore culture of B. campestris, B. nigra, B. oleracea and Raphanus sativus, overcoming the break down of such microspore cultures possibly arising from the release and accumulation of toxic substances into the medium. The modified procedure is as follows: exchange of the incubation medium after one day of culture, addition of activated charcoal to the medium and aerating the three day old microspore culture by agitating the petri dishes on a specially constructed shaker.
Alkenyl Glucosinolate Levels in Androgenic Populations of Brassica napus
Authors: Sieble Jutta , Pauls K. P.
Published: April 2006

The levels of individual and total alkenyl glucosinolates in seeds of microspore‐derived spontaneous diploid plants from low by high and low by low glucosinolate parent crosses were examined to assess the utility of haploidy in canola breeding. The distributions of lines in the populations supported previous proposals that alkenyl glucosinolate levels are under multigenic control. Levels of all of the individual glucosinolates were positively correlated and were significantly reduced in canola‐quality material in comparison to rapeseed‐quality material. The populations of microspore‐derived lines from low × high crosses were skewed to high glucosinolate levels but the population from a low × low glucosinolate cross had a greater proportion of low glucosinolate lines. The former observations can be explained in terms of the dominance of genes for high glucosinolate levels in Brassica napus. The present findings contradict previous reports that androgenic lines have higher glucosinolate content than the parents and in fact, haploidy may select for low glucosinolate lines when crosses between low glucosinolate parents are used.
Comparison of Progeny‐Testing Methods in Lolium perenne L.
Authors: Posselt U. K.
Published: April 2006

From 28 genotypes, half‐sib families were generated by polycross (PX) and 2 topcrosses (TC). TC‐testers were partially inbred cms‐lines. Progenies were tested for annual dry matter yield in 3 successive years. The three year average was 80.7, 76.6 and 74.0 dt/ha for TC 1, PX and TC 2, respectively. TC 1 had the highest yielding families and the largest mean in all years. TC 2 revealed the largest range among its families. Genetic variance was highest for TC 2 with 14.02, followed by TC 1 and PX with 12.05 and 10.92. However, genotype × year interaction variance was about 2 and 4 times greater for TC 1 and TC 2 as compared to PX. Genetic correlation between testcross progenies was tightest for PX vs. TC 1 (rg = 0.644++), while between the two TC's only rg = 0.307+ was observed. Predicted response to selection yielded very similar results for all test‐crosses.
The Pedigree of German Oat Cultivars (Avena sativa L.) and the Occurrence of Fatuoids
Authors: Bickelmann U.
Published: April 2006

A pedigree of German oat cultivars is presented. Accordingly, the cultivars can be assigned to a few distinct lineages originating in crosses between initial landraces. The parentage of white/yellow cultivars includes crosses with black oat. Fatuoids were found in 25 German and foreign cultivars. Every lineage of the pedigree comprises cultivars known for forming fatuoids as well as cultivars up‐to‐now fatuoid free. Fatuoids were found in old and new cultivars. The difficulty of detecting fatuoids in field inspection or seed testing is discussed. The results show that the origin of fatuoids is not related to the lineage of the corresponding cultivars. The hypotheses on the origin of fatuoids arc discussed in relation to the oat pedigree.
A Chromosomal Variant Regenerated from Embryo‐Derived Callus of a Cross between H. vulgare L. and Psathyrostachys fragilis (Boiss.) Nevski
Authors: Pickering R. A.
Published: April 2006

A hybrid plant was regenerated from embryo‐derived callus after crossing Hordeum vulgare with Psathyrostachys fragilis. A mciotic analysis of pollen mother cells revealed the frequent occurrence of one ring bivalent and twelve univalents. It appeared that eight H. vulgare and six P. fragilis chromosomes were present and an unknown duplicate H. vulgare chromosome had compensated for the loss of one P. fragilis chromosome. Although it remains unclear whether the anomaly was present in the original explain or had occurred during the callus phase, the technique could be used to investigate genome homology between the two species.
Comparison of Progeny‐Testing Methods in Lolium perenne L.
Authors: Posselt U. K.
Published: April 2006

From 22 genotypes, selfed (S1) and testcross progenies were investigated. The latter were generated by i) polycross (PX) and ii) 2 topcrosscs (TC) using cms‐inbred lines as a tester. Progenies were tested for annual dry matter yield in 3 successive years, the 3‐year average was 76.7 dt/ha for S, and 76.9, 80.1 and 74.5 for PX, TC 1 and TC 2, respectively. Genetic variance was highest for S1 (20.42), while the average of the 3 tcstcrosses was 12.22. However, the genotype‐year interaction variance of S, Was 52.21, being 2–3 times greater than for the 2 topcrosscs. PX progenies were the most stable across years. Predicted response to selection was highest for S1 (10.4 %). Genetic correlation (rg) between S1 and the testcrosses was highest with TC 2 (rg= 0.593144).
Genotypic Variation in Maize Shoot Biomass at Different Stages of Development
Authors: Léon J. , Geisler G. , Thiraporn R. , Stamp P.
Published: April 2006

A diallel cross from nine early‐maturing lines of maize was grown in northern Germany during 1981 and 1982 in order to study the genotypic variation of shoot biomass at early and late stages of development. Inbred lines had been chosen from breeding programmes for early and medium early cultivars. Nevertheless, the date of maturity varied between them which can have some influence on the correlation between plant parameters. Plants were harvested at the fourth and sixth leaf stages, at anthesis and at maturity. S.c.a. effects were highly significant for traits during the vegetative stage. G.c.a. effects were highly significant for traits of the mature plant including grain yield components. The ratio of g.c.a. to s.c.a. effects for shoot biomass was dominated throughout the growing season by s.c.a. effects. Hybrids from the diallel cross had a superior growth rate until the fourth leaf stage; thereafter, relative growth rates of lines and hybrids were similar for the average of both groups until maturity. The correlation of g.c.a. effects and s.c.a. effects between shoot biomass throughout the season revealed that no significant relationship existed between early and late stages. G.c.a. and s.c.a. effects for grain yield components, with the exception of hundred kernel weight, were negatively correlated with shoot biomass at an early stage while correlation was positive at maturity. This would probably make it a difficult task to improve shoot growth and grain yield components simultaneously through the season.
The Diploidised Meiosis of Tetraploid Beta macrocarpa and its Possible Application in Breeding Sugar Beet
Authors: Lange W. , de Bock Th. S. M.
Published: April 2006

Accessions of Beta macrocarpa Guss., collected on the Canary Islands, were tetraploid (2n = 36). Three of these accessions were studied in detail. The plants were rather uniform in their morphological appearance, both within and between accessions, and were annual and fully self‐compatible. Meiosis was completely diploidised, suggesting an alloploid nature of the tetraploid species. Crosses with diploid B. vulgaris yielded triploid hybrids which were sterile or nearly so; a few descendants of such hybrids were highly aneuploid. Crosses between tetraploid B. macrocarpa and autotetraploid cytotypes of B. vulgaris showed variable results, only part of these crosses yielded tetraploid hybrids. The tetraploid hybrids exhibited somewhat higher fertility than the triploids. An F2 generation showed partial hybrid dwarfness, partial fertility and segregation for carliness and coloration of the hypocotyl. All hybrids had multivalents at meiosis (averages: 2.5—5.4 multivalents per pollen mother cell), indicating suppression of the diploidised meiosis. The possibilities of application of the diploidised meiosis in breeding sugar beet are discussed.
Distribution and Origin of Hybrid Necrosis Genes in German Winter Wheat (Triticum aestivum L.) Cultivars
Authors: Oetmann Anja , Zeller F. J.
Published: April 2006

Hybrid necrosis in Triticum is known to be caused by the interaction of two complementary dominant genes. In the present paper, the genotypes for hybrid necrosis of 64 winter wheat cultivars are presented. 41 cultivars were found to possess the Ne2 necrosis gene, whereas 23 cultivars were non‐carriers. The Ne1 gene was not found in any of the cultivars analyzed.
Resistance to the Potato Leafroll Virus (PLRV) in Diploid Potatoes
Authors: Swiezynski K. M. , Dziewonska M. A. , Ostrowska K.
Published: April 2006

A high level of PLRV resistance has been found in four diploid genotypes originating from resistant ancestors widely utilized in European potato breeding. Plants of these genotypes were difficult to infect not only with aphids, but also with graft inoculation. Their resistance is associated with limited virus spread, but not with intolerance.

The level of PLRV resistance in these genotypes appears to be comparable to a high level of resistance detected recently in some wild potato species.

Evaluation of virus concentration after graft inoculation with PLRV was found useful in the selection of potato genotypes highly resistant to PLRV.
Sexual Transmission of Somatic Embryogenesis in Dactylis glomerate*
Authors: Gavin Anita L. , Conger B. V. , Trigiano R. N.
Published: April 2006

A Dactylis glomerata L. genotype that produces somatic embryos in vitro was tested for the ability to sexually transmit the embryogenic trait. Reciprocal crosses were performed between the embryogenic and two non‐embryogenic genotypes. Leaf segments from 69 F1 plants were cultured on Schenk and Hildebrandt medium amended with 30 μM 3,6‐dichloro‐o‐anisic acid (dicamba). Somatic embryogenesis was expressed in 39 of the F1 plants. The embryogenic parent was female for 18 of these plants and male for the other 21. The 39:30 ratio of embryogenic: non‐embryogenic fits an expected 1:1 for tetrasomic inheritance of a dominant nuclear gene.
Inheritance of the Powdery Mildew Resistance Mlk in Wheat
Authors: Heun M. , Fischbeck G.
Published: April 2006

The inheritance of the Mlk powdery mildew resistance originating from ‘Heine 2174.50’ was analyzed by crossing the Mlk resistant cultivar ‘Ralle’× cv. ‘Amor’ (highly susceptible) and vice versa and by observing the reactions of F1‐ and F2‐plants after inoculation with two different Mlk avirulent powdery mildew isolates. In all cases, a 3 (resistant): I (susceptible) segregation was found in F2. The reactions of the F2plants against the two powdery mildew isolates were identical in each case. Therefore, it is supposed that one dominant resistant gene is responsible for the resistant reactions against these two isolates. These results support the earlier assumption of Heun and Fischbeck (1987b) that the whole Mlk resistance pattern is controlled by a single gene.
Observed and Predicted Genetic Gains from Single and Multi‐Trait Selections Using Three Mating Designs in Pearl Millet*
Authors: Zaveri P. P. , Phul P. S. , Dhillon B. S.
Published: April 2006

The objectives of the study were to estimate the genetic components of variance, predict the response to selection and to evaluate observed response to selection using two populations namely, PSB 7 and PSB 3, of pearl millet (Pennisetum americanum [L.] Leeks). The observed response was studied using four methods of selection based on single and multitrait criteria in three types of families, namely S1, half‐sib (HS) and full‐sib (FS) families. One hundred SI, HS and FS families each were developed in PSB 7 and PSB 3. Plants within a population were pollinated with bulk pollen of other population to develop HS families. Crosses were made between a pair of plants using one plant from each of the two populations to develop PS families. Data were recorded on days to flower, plant height, tiller number, spike length, spike girth, seed yield per plant and spike weight. Additive genetic variance estimates were significant for all traits. The estimates of dominance and additive × location and dominance × location interaction components were not significant, except additive × location component in PSB 7 for seed yield and spike weight. The genotypic component of variance among S1 families and S1 × location interactions were significant except S1 × location interactions in PSB 7 for days to flower, spike length and spike girth.

Twenty‐four strains were developed by intermating superior families identified on the basis of four selection methods in each of the six types of families.

The selection methods were high seed yield (YS) per se; index selection (IS) for high tiller number and long and thick spike; truncation selection (TS) for high yield among the families having days to flower and plant height lower than the population mean: and visual selection (VS) after completion of flowering for good vigour, uniformity in plant height and good inflorescence attributes. YS and IS were found to be superior to TS and VS with respect to observed genetic gains for seed yield. That advance was higher in selection among SI families as compared with FS and HS families. In general, a good agreement was noted between observed and expected responses. Expected genetic gain from FS reciprocal (R) recurrent selection was higher than the average gain from HS‐R selection.
Mapping of Equipotential Zones for Cultivar Yield Pattern Evaluation
Authors: Gusmāo L. , Mexia J. T. , Gomes M. L.
Published: April 2006

Using data from a triticale advanced line yield trial network, we attempt to define the zones, in Portugal, within which the joint regression can be established with enough accuracy and precision to be of practical value.

The procedure comprises the following steps: adjustment of the joint regressions for the whole area; evaluation of the residuals in each trial; previous identification of geoclimatic zones; comparison of these zones with the residuals; adjustment of the regressions for the zones confirmed in the previous analysis, and testing the differences between the regressions for each zone.

The experimental conditions allowed the differentiation of two main zones: “Nordeste Transmontano” and “Sul de Montejunto‐Estrela”, however, another zone, included in the latter and designated “Alentejo Litoral e Algarve”, is suggested though further experimental data are needed for sound conclusions.
Effect of Induced Autotetraploidy on Response to Sclerotinia Clover Rot in Trifolium pratense L.
Authors: Arseniuk E.
Published: April 2006

The effect of induced autotetraploidy on the response of red clover to Sclerotinia clover rot (SCR) was studied under laboratory, glasshouse and field conditions. To assess the response in the laboratory, the detached leaf technique was employed, whereas in the glasshouse and in the field, 6—14 weeks old seedlings and adult plants, respectively, were artificially inoculated with the pathogen grain inoculum.

The results of the studies showed that great genotypic variability occurs within diploid (2×)and tetraploid (4×)red clover in response to that disease. Generally, tetraploid red clover, in comparison to diploid, is more resistant to SCR. The laboratory, glasshouse and field experiments showed that the effect of induced autotetraploidy on SCR resistance is positive. The hardening of plant with light and temperature enlarged the differences in reponse to SCR between ploidy levels, family pairs and individual strains with every testing method.

Other factors, like plant age and flowering time, influencing red clover response to SCR are also discussed.
Diversity for Disease Resistance in Barley Landraces from Syria and Jordan
Authors: van Leur J. A. G. , Ceccarelli S. , Grando S.
Published: April 2006

A number of barley landraces collected in Syria and Jordan were evaluated for resistance to yellow rust, powdery mildew, scald and covered smut by inoculating single‐head progenies with local pathogen strains during two years of field tests. A large diversity in resistance was observed for each pathogen both between populations of different collection sites as well as between head progenies within collection sites. The level of resistance varied from absolute and partial resistant types up to highly susceptible lines. No consistent association between the environmental conditions of the collection site and the level of resistance of the landrace‐lines could be found.
Early Generation Selection for Grain Yield in Narrow‐Leaf Lupin (Lupinus angustifolius L.)
Authors: Thurling M. , Ratinam M.
Published: April 2006

Experiments were conducted with early segregating generations of a selected narrow‐leaf lupin cross to determine the effectiveness of selection for yield based on alternative criteria.

F2 plants were selected on the basis of seed yield and several other yield‐related characters to generate separate F3 populations. Randomly selected plants from each population were grown over the summer (off‐season) in a glasshouse to generate F4 populations.

Analyses of relationships between F2 plant measurements and F3 progeny mean yields revealed significant correlations only for those characters with the highest heritabilities ‐ flowering time, 100 seed weight and harvest index. However, selection for the earliest flowering F2 plants followed by selection within this group of plants with the highest number of pod bearing branches would result in the greatest increase in F3 mean yield.

The F2‐derived F4 populations with the highest seed yields were those obtained by selection for total plant dry weight, number of pod bearing branches and number of pods per plant. Improvement in commercial crop yield should therefore be obtained through selection in early generations for those characters contributing to the greatest number of pods per unit area.

A scheme involving selection for early flowering and high number of pod bearing branches in the F2 combined with replicated yield tests in the F4 is proposed.
A Study of Fructose Yield Components in Chicory
Authors: D'Eeckenbrugge G. Coppens , Herck J.‐C van , Dutilleul P.
Published: April 2006

2557 chicory roots from 13 cultivars were analysed individually for root weight, root shape, total fructose, total glucose, potassium and amino‐N contents. Fructose yield is highly correlated with root weight and slightly with fructose content, both at the inter‐ and intra‐varietal levels. The comparison of total‐sample correlations to between‐ and within‐variation correlations suggests an important genetic variation within varieties.
Apium Wild Species: Novel Sources for Resistance to Late Blight in Celery
Authors: Ochoa O. , Quiros C. F.
Published: April 2006

Screening of 144 varieties of celery A. graveolens L. for late blight (Septoria apiicola Speg.) resistance resulted in the detection of significant differences for disease reaction. However, each accession displayed greater than 25 % leaf necrosis area due to the disease pathogen. Hence the magnitude of infection in the least susceptible plants was still too great to use them as a valuable source for resistance. The wild species A. chilense and A. panul exhibited a few discrete yellow spots with very little, if any, pycnidial development. This type of resistance was not observed in any accession of celery screened. The degree of resistance was intermediate in the F1 hybrids between A. graveolens × A. chilense and A. graveolens×A. panul, indicating incomplete dominance. The resistance to late blight found in these wild species and their ability to cross with celery provides a novel germplasm source for breeding celery lines with improved resistance to late blight.
Fluorimetric Determination of the Genetic Variability Existing for Chilling Tolerance in Sweet Sorghum and Sudan Grass
Authors: Havaux M.
Published: April 2006

Chilling temperatures drastically inhibited the photochemical quenching of chlorophyll fluorescence (qQ) measured in intact leaves photosynthesizing under steady‐state conditions. This effect appeared, however, to be characteristic of chilling‐susceptible plant species and was not observed in plants which are known to be chilling‐tolerant, indicating that the measurement of qQ can serve in practice to estimate rapidly the relative chilling tolerance of crop plants. A large number (28) of sweet sorghum (Sorghum bicolor) and Sudan grass (Sorghum sudanense) genotypes were screened for chilling tolerance using this rapid qQ method. Although sweet sorghum and sudan grass obviously behaved as chilling‐sensitive plants, a considerable variation for chilling susceptibility was observed among the different genotypes tested. Some sweet sorghum varieties, such as ‘Dale’ and ‘Keller’, and most of the sudan grass varieties appeared to possess a certain degree of resistance towards low temperature stress, indicating the existence of useful germplasms in Sorghum for improving stress tolerance.
Grafting in vitro Regenerated Pea (Pisum sativum L.) Shoots as a Method for Obtaining Mature Plants
Authors: Natali L. , Cavallini A.
Published: April 2006

A method of grafting pea plants is proposed to allow rapid availability of a large number of mature plants from in vitro regenerated shoots.

Plant regeneration was obtained from macerated vegetative apices and immature embryos, but regenerated shoots rooted with low frequency (ca. 10 %). When those shoots were grafted onto seedling stocks of the same cultivar, 80 to 85 % of the grafts survived, grew to maturity and produced seed.
New Genetic Markers in a Wild Species of Beet (Beta nana Boiss. et Heldr.): Prospects for Utilization
Authors: Nagamine T. , Ford‐Lloyd B. V.
Published: April 2006

In a study of variation in 13 enzymes occurring in B. nana, unique and invariant phenotypes were found for five of these enzymes, when compared with a range of other wild and cultivated beets. In similar comparisons unique alleles were found in B. nana for two other enzyme loci. For the remaining six enzymes B. nana was found to have variation and alleles which were common to other forms of beet. It is concluded that reliable markers for B. nana exist, and that this species represents a source of novel genes for sugar beet breeding.
Use of Molecular Markers in Breeding for Oligogenic Disease Resistance
Authors: Melchinger A. E.
Published: April 2006

In several plant species, genetic maps have recently been developed for restriction fragment length polymorphisms (RFLPs). Together with isozymes, they offer alternative solutions to many breeding problems. This review deals with the current and potential uses of molecular markers in breeding for oligogenic resistance traits.

In the first part, segregation analyses and analyses of near‐isogenic lines are collated with respect to the mapping of resistance genes. Also, various types of populations are compared for the amount of information obtained in segregation analyses. In the second part, theoretical and numerical results are presented dealing with the number of individuals required for marker‐facilitated selection of a resistance gene in a backcross program. Both the use of a single marker and a marker bracket are considered and the influence of the following parameters is investigated: (a) recombination frequency between the resistance gene and marker(s), (b) size of backcross families, (c) number of backcross generations, and (d) number of carriers of the resistance gene to be recovered in the final backcross generation. The results provide information with regard to the optimum design of marker‐facilitated selection programs and the required expenditures compared to direct selection of the resistance trait. In the third part, applications of molecular markers are discussed with respect to (1) advantages of marker‐facilitated selection for resistance genes under a variety of special circumstances, (2) pyramiding of resistance genes, (3) selection against the genetic background of a donor parent, and (4) their use as a starting point for chromosome Walking.
Hybridization of Sinapis alba L. and Brassica napus L. via Embryo Rescue
Authors: Ripley Van L. , Arnison P. G.
Published: April 2006

Embryo rescue techniques were used to obtain hybrids between Sinapis alba L. (white mustard) and Brassica napus L. (oilseed rape) with the goal of improving the disease tolerance of oilseed rape. Hybrid plants with 31 or 43 chromosomes were only recovered, when S. alba, was used as the female parent. One hybrid was obtained from the cross S. alba L. cv. ‘Kirby’×B. napus L. cv. ‘Topas’, while 26 hybrids were obtained, when various S. alba L. cultivars were pollinated with the rapid cycling B. napus line CrGC 5006. All F1, hybrid plants were male sterile; however, the first generation backcross to B. napus L., also obtained by embryo rescue, produced plants with 50 chromosomes and 61–84 % pollen viability. Second backcross generation seed was produced by normal sexual crossing. Preliminary cytological analyses of pollen mother cells of hybrid plants suggests the possibility of genetic exchange between the two species.
Influence of Telomeric Heterochromatin Loss on Growth and Development of the Early Embryo and Endosperm in Triticale
Authors: Dillé J. E. , Gustafson J. P.
Published: April 2006

The influence of telomeric heterochromatin on early embryo and endosperm development and the production of aberrant endosperm nuclei were investigated using eight triticale (×Tritocmecale Wittmack) lines homozygous for the presence or absence ol blocks of telomeric heterochromatin from rye chromosome arms 1RL, 2RS, (SRS, and 7RL. The loss of heterochromatin from two chromosomes (6R, 7R) produced a significantly lower percentage of aberrant endosperm nuclei than did the loss from one chromosome (6R). Deletion of a third block had a significant additional effect in only one of four lines. The differences between lines for rales of embryo and endosperm development were significant even within a karyotypc, presumably because of genetic variation. The onset of cellularization of the endosperm tended to obscure the detection of aberrancy, and since it evidently occurred at different times in different lines, may have been largely responsible for the apparent reduction in aberrant nuclei in lines with less heterochromatin.
Recurrent Mass Selection for Reduced Seed Dormancy in Cuphea lanceolata and Cuphea laminuligera
Authors: Knapp S. J.
Published: April 2006

Seed dormancy is a domestication barrier in certain Cuphea species. Between and within species variation has been observed for seed dormancy in agronomically promising Cuphea species, e.g., C. laminuligera Koehne and C lanceolata Ait. In tins note, we report on progress made in reducing seed dormancy through recurrent mass selection in the C. lanceolata population LN43 and LN78. The germination percentages of unselected LA12 and LN43 populations increased from 0.0 % to greater than 95.0 % following an after‐ripening period of 20 weeks. We observed no germination percentage differences between unselected and selected LN43 populations following two cycles of selection. In contrast, there were highly significant differences between the unselected and selected populations of LA12 following two cycles of selection. The germination percentages of cycle zero (C0) and cycle two (C2) populations after‐ripened 10 weeks were 10.7 and 92.7 %, respectively. After one cycle of selection in the C. Lanceolata population LN78, the germination percentage of seed after‐ripened 10 weeks had increased from 1.3 % for the Co population to 28.7 % for the C0 population. In summary, mass selection greatly reduced seed dormancy in LA12 and LN78, but had no effect in LN43.
Genomic Relationships of Triticum sharonense with Other S‐Genome Diploid Triticum Species
Authors: Yen Yang , Kimber Gordon
Published: April 2006

Triticum sharonense was hybridized with autotetra‐ploid T. speltoides, T. longissimum and T. bicorne. Meiotic analysis of these hybrids showed that T. sharonense is almost equally related to both T. speltoidcs and T. longissimum, while it is comparatively distant from T. bicorne. Therefore, this study does not support treating T. sharonense as a subspeies or variety of T. lottgissimum.
Performance and Variability of Local Barley Landraces in Near‐Eastern Environments
Authors: Weltzien E. , Fischbeck G.
Published: April 2006

Homozygous lines from six Syrian and two Jordanian landrace populations were tested under highly productive growing conditions in Tel Hadia (1982/83), under drought stress in Breda (1983/84), and under dryland salinity stress in Hegla (1982/83/84) in Syria. Mean grain yield levels ranged between 260 kg/ha and 4850 kg/ha. Under drought and salinity stress, the majority of the landrace lines out‐yielded the best cheeks significantly. In Tel Hadia the check cultivars mostly outyielded the landrace lines, but not always significantly. In all environments the harvest index of the landrace lines was near the optimum for barley. They expressed intermediate plant height and time to flowering, high lodging susceptibility under favorable growing conditions, high protein content, and a wide range of yield component combinations.

In the stress environments highly significant genetic variation among the landrace lines was found. The heritabilities for gram yield were high in these trials. The correlations between performance under stress and under favorable growing conditions were poor. Therefore, the largest gains for variety improvement for the Syrian steppe area are expected from direct selection under stress conditions.

Unique responses in proline accumulation and germination patterns in saline solution indicated specific adaptation in this material. These landraces, thus, are a useful source of breeding material, which also widens the genetic base of the present breeding program.
Segregation of Isozyme Marker Loci Amongst Androgenetic Plants of Lolium perenne L.
Authors: Hayward M. D. , Olesen A. , Due I. K. , Jenkins R. , Morris P.
Published: April 2006

The segregation of isozyme markers has been examined in the green and albino androgentic progenies of two plants of Lolium perenne. Overall the pooled data for the loci PG1/2 and GOT/2 does not deviate from expectation, but there is considerable heterogeneity between families and between green and albino plants. Specific alleles predominate in the different progeny sets. The results may be accounted for by possible linked loci affecting anther culture response or of linked lethal genes.
Improvement of Salt Tolerance in Maize by Selection and Breeding
Authors: Ashrai M. , McNelly T.
Published: April 2006

Genetic variation for NaCl tolerance at the vegetative stage was assessed in nutrient solution culture in maize (Zea mays L.). Shoot growth, and plant fresh and dry weight of the two cultivars, Akbar and Sadat were severely reduced after three weeks growth in 120, 150, and ISO mol m−3 NaCl. There was however considerable variability between seedlings. Ten‐thousands seeds of cv. Akbar were therefore screened for shoot growth at 180 mol m−3 NaCl after four weeks growth in sand culture. A selection intensity of 0.42 % was achieved. Eighteen selected plants were polycrossed for estimation of narrow‐sense heritability based on female parent‐progeny regression. A narrow‐sense heritability estimate of 0.54 was obtained.

The progeny of the salt‐tolerant selection line and selfed progeny plants of the unselccted control lines of cvs Akbar and Sadat were grown for six weeks in 0, 30, 60, 90, 120, 150, and 180 mol m−3 NaCl in sand culture. The tolerant line produced significantly greater fresh and dry biomass and had greater shoot length than the unselected cv. Akbar, but the selection line derived from cv. Akbar was equal to the salt tolerant cv. Sadat in all the growth parameters measured.

These data suggest that in maize, improvement in salt tolerance could be obtained through further cycles of selection and breeding.
Genetic Variation in the Ability of Detached and Partially Dehydrated Leaves of Rice to Accumulate Abscisic Acid, Measured by Radioimmunoassay
Authors: Bilsnorrow P. E. , Quarkif S. A. , Henson I. E.
Published: April 2006

Variation in the ability o) 60 rice (Oryza saliva L.) varieties and three wild species to accumulate abscisic acid (ABA) in response to drought stress, drought‐induced ABA accumulation (DIAA), was assessed using a standard detached‐leaf lest. The range in DIAA amongst these genotypes was compared with the range amongst F2 plants and F6, lines derived from the O. saliva cross ‘IR20’×‘63–83’ which were selected through several generations solely on the basis of differences in DIAA. ABA was measured by radioimmunoassay (RIA) or by gas chromatography (GC).

DIAA in the 60 varieties was normally distributed with a six‐fold range, from 245 to 1580 ng g−1 FW. Wild species varied two‐fold in DIAA, from 375 to 889 ng g−1 FW. DIAA in F2 plants from the ‘1R20’×‘63–83’ cross was also normally distributed. The extremes of DIAA for the low‐ABA and higb‐ABA F6 lines (330 and 1435ng g−1 FW) were similar to those for the varieties. Measurements by RIA and GC gave similar results.

These findings are discussed in the context of producing further sets of closely‐related genotypes with similar leaf areas to study the association between DIAA and water‐use efficiency.
Culture Associated Variation in Maize Inbreds
Authors: Cowen N. M. , Thompson S. A. , Wilkinson Thekksa C.
Published: April 2006

The extent of culture associated variation generated by a brief passage through tissue culture was evaluated in four maize inbred backgrounds: A641, H99, MS7I, and PA91. The progeny resulting from two generations of self‐pollination from the original regenerates were evaluated along with appropriate sexual controls in a replicated field experiment. Eighty regenerate lines and twenty controls were evaluated in each background. Data were collected for 22 traits and were subjected to analysis of variance, discriminant analysis, and principal component analysis. In 58 of 88 combinations of background and trait, the contrast of controls vs. regenerates was significant. The culture cycle increased the variation and changed the association between traits. Testcross hybrids involving these regenerate lines and controls were also evaluated with little or no significant variation or differences between regenerate hybrids and controls being detected.
An Analysis of Seed Development in Pisum sativum L. IX. Genetic Analysis of Lipid Content
Authors: Jones D. A. , Arthur A. E. , Adams H. M. , Coxon D. T. , Wang T. L. , Hedley C. L.
Published: April 2006

The objective was to study the genetic basis of lipid content in pea seeds and the extent to which the inheritance of lipid content can be attributed to major genes determining seed shape. The genetic analysis consisted of two full 5 × 5 diallel crosses; one diallel between genotypes differing for genes affecting seed shape (r, rb, di and mifo loci) and the other between genotypes known to differ for lipid content. The results indicated that there was significant additive genetic and dominance variation for percent lipid. Recessive alleles at the r and rb loci have a positive effect on lipid content, while alleles at the di and mifo loci appear to have no effect on lipid content.
Preferential Transmission in Bread Wheat of a Chromosome Segment Derived from Thinopyrum distichum (Thunb.) Löve
Authors: Marais G. F.
Published: April 2006

A Thinopyrum distichum chromosome segment translocated on chromosome arm 7DL. of the line ‘Indis’, was shown to be preferentially transmitted in crosses with other bread wheats. The translocated segment carries a gene for leaf rust resistance and produces a null condition for the endopeptidase product, EP‐Dla. These characters were used to follow the transmission of the translocated chromosome in segregating and testcross progenies derived by crossing ‘Indis’ to four bread wheat cultivars. The severity of the gametocidal response in the heterozygotes ranged from a virtually exclusive transfer of the translocation to an almost normal transmission of the homologues. In some genetic backgrounds an intermediate level of transmission occurred. In the F1 with a gametocidal response, the transmission of the normal chromosome 7D was reduced in both sexes, but the reduction may be more severe in the male germline.
Plant Regeneration and Chromosomal Stability in Tissue Cultures of the Hybrids of Elymus canadensis with Psathyrostachys juncea and Secale cereale
Authors: Park C. H. , Kumar P. S. , Walton P. D.
Published: April 2006

Callus was induced from segments of immature inflorescences of Elymus canadensis×Psathyrostachys juncea and Elymus canadensis×Secale cereale F1 hybrids on MS medium supplemented with 2 mg/l of 2,4‐D and plants were regenerated from the calluses on a hormone free MS medium. The plants regenerated from both the hybrids exhibited a high degree of stability in morphology, chromosome number and chromosome pairing. The reasons for this are discussed.
Electrophoretic Characterization of Quinoa Seed Proteins
Authors: Fairbanks D. J. , Burgener K. W. , Robison L. R. , Andersen W. R. , Ballon E.
Published: April 2006

Quinoa (Chenopodium quinoa Willd) is an important domesticated food crop of the Andean highlands with potential as an alternative crop elsewhere. Among its most attractive characteristics are the quantity and favorable amino acid balance of the seed proteins. The objective of this study was to characterize quinoa seed proteins by electrophoretic mobility, solubility fractionation, and genetic variability from a wide genetic base. Electrophoretic profiles of denatured albumin, globulin, prolamin, and glutelin solubility fractions demonstrated that quinoa seed polypeptides could be classified as either albumin or globulin with most predominant polypeptides in the globulin fraction. Insignificant amounts of protein were present in the prolamin fraction and all polypeptides in the glutelin fraction had identical electrophoretic mobilities to albumins and globulins. Three globulin polypeptides of 34.3, 35.6, and 36.2 kilodaltons in size were highly variable within and among the accessions examined and appear to be coded by at least two loci. Two‐dimensional peptide mapping revealed that these three polypeptides were homologous. These highly variable markers could be used for identification and classification of germplasm and elucidation of systematics and genetic variability within the quinoa germplasm pool. All other major polypeptides were electrophoretically invariant among the accessions examined.
Electrophoresis of the Seed Proteins of Vicia faba L. and Its Immediate Progenitors — A Reappraisal
Authors: Sammour R. H.
Published: April 2006

Electrophoretic patterns of total seed protein analyzed by polyacrylamide gel electrophoresis under non‐dissociating and dissociating conditions were found to have diagnostic value for the Vicia species. The close similarity in the seed protein profiles of the cultivated species and Vicia narbonensis narbonensis indicated that this last species can be considered as the immediate progenitor of V. faba. The study also indicated that V. serratifolia should be included as a subspecies in V. narbonensis.

The broad bean, Vicia faba, is one of the most important leguminous pulses cultivated over a wide range (from Central Asia to Western Europe and from Ethiopia and Sudan to Scandinavia). Schultz‐Motel (1972) was the first to identify remains of V. faba seeds from archeological sites of the Bronze Age, mainly from Central and Southern Europe. Recently, Kislev (1985) found charred seeds of horsebean (V. faba L.) from the 7th millennium B.C. Thus, horsebean should be included among the legumes grown by some early Neolithic people.

Zohary and Hopf (1973) have suggested that the wild ancestors of V. faba are species belonging to section Faba. In particular, the French vetch V. narbonensis L., was the promosing candidate; most probably, because the area of distribution of V. narbonensis coincides with that of V. faba. On the other hand, Ieibe (1934), Ladizinsky (1975), and Abdall and Gunzel (1979) refuted the reports that V. narbonensis (and wild species from the section Faba) may be considered as immediate ancestors of the cultivated species of V. faba. These authors reported on the albumin profile of seed protein in Vicia.

This study aims to reassess the relationships between V. faba and its taxonomically related species in terms of their storage protein profiles and present some information on the evolution of V. faba.
Meiotic and Isozymic Analyses of Tall Fescue × Giant Fescue Hybrids and Amphiploids1
Authors: Eizenga G. C. , Burner D. M. , Buckner R. C.
Published: April 2006

The meiotic behavior of three tall fescue (Festuca arundinacea, 2n = 6x = 42) genotypes, giant fescue (F. gigantea, 2n = 6x = 42), and their reciprocal F1 hybrids and C1, amphiploids was evaluated to determine the parental genomic relationships. Isozyme banding patterns were used to confirm the parental identity of the hybrids and amphiploids. At meta‐phase I, the parents had predominantly bivalent pairing. The hybrids had an average of 9.51 I, 16.02 II, 0.12 III, 0.02 IV, and the amphiploids had 2.17 I, 38.82 II, 0.60 III, 0.58 IV, 0.01 V—VIII. The prevalence of bivalent pairing in both hybrids and amphiploids suggested a homoeologous relationship between the six genomes, with four of the six being more closely related. Bivalent pairing in the amphiploids indicated genetic regulation of chromosome pairing. Zymograms were obtained for acid phosphatase (ACPH), alcohol dehydrogenase (ADH), glutamate oxaloacetate transaminase (GOT), malate dehydrogenase (MDH), 6‐phosphogluconate dehydrogenase (6‐PGD) and phosphoglucoisomerase (PGI). The three tall fescue and giant fescue parents had different zymograms for ACPH, MDH, 6‐PGD and PGI; thus, the tall fescue parents of the hybrids and amphiploids could be determined based on the banding patterns of these four enzymes. Phenotypes were determined for ACPH‐1, PGI‐2 and 6‐PGD‐1. ACPH‐1 may be used to follow the introgression of giant fescue chromatin into a certain tall fescue genotype.
Genetic Control of Abnormal Seedling Development in Phaseolus vulgaris L. and P. vulgaris×P. acutifolius A. Gray Hybrids
Authors: Scott M. E. , Michaels T. E.
Published: April 2006

Abnormal hybrid seedling development hinders attempts to introgress diverse germplasm in common bean (Phaseolus vulgaris L.) breeding programs. In this study, the hypothesis that DL1 and DL2 loci control abnormal seedling development both in Phaseolus vulgaris L. intraspecific hybrids and in P. vulgaris×P. acutifolius A. Gray interspecific hybrids was tested. Hybrids from crosses between six P. vulgaris lines (two Andean dl1 d1, DL2DL2, two Mesoamerican DL1DL1 dl2 dl2, and two facilitators dl1dl1, dl2dl2) and P. vulgaris cultivar Ex Rico 23 developed normally, indicating that Ex Rico 23 has the facilitator genotype dl1, dl1, dl2dl2. Previous studies have shown that Ex Rico 23 ×P. acutifolius results in abnormal seedlings, but ‘ICA Pijao’, also dl1, dl1 dl2dl2, ×P. acutifolius results in normal seedlings. Neither the Andean nor the Mesoamerican lines crossed successfully with P. acutifolius, but crosses between one of the two facilitators (G3807) and P. acutifolius resulted in normal seedlings. These results support the hypothesis that different loci control intra‐ and interspecific hybrid seedling development.