bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Drechslera (Helminthosporium) sacchari Toxin upon the Permeability of Sugarcane Leaf and Callus Tissues
Authors: Leal M. Ramos , Maribona R. H.
Published: April 2006

Sugarcane leaves and calli from highly susceptible and resistant varieties to eyespot disease were used to evaluate the Drechslera sacchari toxin effect at different concentrations and incubation times by measuring electrolyte leakage. This expression of disease resistance was observed not only in the leaf but also in the callus. Furthermore, the growth of resistant calli MS medium supplemented with DS toxin, was higher when compared to the susceptible ones. The possibility of obtaining resistant somaclones is confirmed.
Analysis of Competitive Ability among Clones of the Palisade Grass, Brachiaria brizantha (Hochst. Ex. A. Rich.) Stapf.
Authors: Senanayake S. G. J. N. , Petersen H. L.
Published: April 2006

Four clones of palisade grass, Brachiaria brizantha (Hochst. Ex. A. Rich.) Stapf., were studied in a diallel competition trial to investigate their competitive relationship in clonal mixtures. Clone X associate interactions were observed for plant height, number of tillers per plant and dry matter yield per plant. Both general and specific competitive abilities were observed for tiller number and dry matter yield. Clone X associate interaction for plant height was mainly due to the specific competitive ability of individual combinations. The most competitive clone observed was CIAT 6387. Competitive abilities of local clones were low compared to the imported clones. Local clones (RU 127 and RU 139) yielded more than imported clones (CIAT 6387 and PI 292185) under low competitive stresses. General and specific competitive abilities should be taken into consideration when mixing clones of palisade grass.
Factors Affecting the Differentiation of Resistant Faba Bean Plants after Inoculation with Sclerotinia trifoliorum
Authors: Lithourgidis A. S. , Roupakias D. G. , Tzavella‐Klonari K.
Published: April 2006

Faba bean (Vicia faba L.) plants 3, 4, 5 and 6 weeks old were inoculated at different internodes by carrot root pieces colonized by the fungus Sclerotinia trifoliorum Eriks. The plants were left in the growth chamber for 72 h. In addition, eight faba bean cultivars, 4 weeks old, were inoculated by the same inoculum which was left on the stems for various lengths of time. When the inoculum was removed, the plants were scored for disease severity. The highest disease seventy was on the youngest tissues inoculated. Susceptible and partially‐resistant cul‐tivars could be differentiated effectively when the inoculum was removed 48 to 72 hours after the inoculation.
Breeding Progress in Small Grain Cereals — A Comparison of Old and Modern Cultivars
Authors: Feil B.
Published: April 2006

The present paper reviews the results of comparative studies on old and modern small grain cereal cultivars. The contribution of genetic improvement to the increase in grain yield and the influence of environmental factors on the performance of old and modern cultivars are discussed. The evolution of grain yield components and the effects of breeding on numerous physiological, morphological and biochemical characteristics such as formation of above‐ground biomass, havest index, total N uptake, N harvest index, N concentration in the grains, canopy structure, carbon dioxide exchange, tiller survival, root growth, course of development and enzyme activities are considered.
The Influence of Silver Thiosulfate on Potato Protoplast Cultures
Authors: Möllers C. , Zhangm S. , Wenzel G.
Published: April 2006

The influence of silver thiosulfate (STS) on the in vitro shoot propagation of twenty dihaploid potato clons and their protoplast regeneration to plants was investigated. The addition of 1.5 mg/1 STS to the propagation medium led to an incrase of leaf material harvested per culture vessel. Depending on genotype, the increase ranged from 1.2 up to 2.3 times the yield obtained from medium without caused toxic symptoms in the plants to most of the genotypes tested, and it was not possible to isolate viable protoplasts. The addition of STS to the shoot regeneration medium considerably promoted the shoot regeneration from protoplast‐derived calli. This effect again was strongly genotype‐dependent.
Genetic Variation for Anther Callus Inducibility in Crosses of Highly Culturable Winter Wheats
Authors: Becraft P. W. , Taylor G. A.
Published: April 2006

Heritability studies suggest that variation among genotypes for callus inducibility should respond to selection. The objective of this study was to determine if crosses among parents with high callus initiation frequencies would produce segregation from which genotypes with improved callus inducibility could be selected. The winter wheat (Triticum aestivum L.) cultivars‘Centurk 78’, ‘Norstar’ and ‘Norwin’ were chosen as parents, based on their high callus initiation frequencies and diverse parentage. F2 populations from crosses between each of these parents were evaluated for callus initiation frequencies and callus vigor as determined by growth rate and healthy appearance. Heterosis was detected for callus initiation in the‘Norwin’×‘Norstar’ cross and for callus vigor in all crosses. Broad sense heritability estimates of 0.25 and 0.37 for callus initiation in the ‘Centurk 78’×‘Norstar’ and ‘Norwin’×‘Norstar’ crosses, respectively, suggest this trait can be improved by selection. Heritability estimates for callus vigor were less promising, ranging from 0.11 to 0.24.
Race‐Specific Resistance Genes Against Erysiphe graminis f. sp. hordei in Old and Recent French Barley Accessions
Authors: Andrivon D. , de Vallavieill‐Pope C.
Published: April 2006

Leaf segments from seedlings of 68 old barley varieties and 38 more recent cultivars of past or current importance in France were infected with 6—9 powdery mildew isolates in order to identify race‐specific resistance genes. No resistance gene was apparent in the 21 old winter varieties, 43 of 47 old spring varieties, 10 recent winter and 3 recent spring cultivars. Two old spring varieties (‘Colmar S 142’ and ‘Johanna’) were postulated to have Mlg and Ml(CP), and two others (‘Pontrieux’ and ‘Finistère 62‐5’) had an unidentified, weakly effective gene. Mlg, Ml(CP), Mlb, Mla6 and Mlal3 were the only genes detected in recent winter cultivars. Recent spring cultivars presented the greatest diversity; the presence of one or several genes among Mlal, Mla6, Mla9, Mla12, Mlg, Ml(CP), Ml(La), Mlk and mlo was postulated in several lines.
Chromosomal Location of Genes for Gibberellic Acid Insensitivity in ‘Chinese Spring’ Wheat by Tetrasomic Analysis
Authors: Börner A. , Worland A. J. , Law C. N.
Published: April 2006

The tetrasomics of the homoeologous groups 2, 5 and 7 of‘Chinese Spring’wheat were, together with the euploid standard, screened at the seedling stage for sensitivity to exogenously applied gibberellic acid (GA3). Whilst the seedling length of lines tetrasomic for group 2 chromosomes were taller and those for chromosomes 5A, 5D and 7D shorter in both treatments (with and without GA3) compared to the euploid control, the remaining tetrasomics — 5B, 7A and 7B — were significantly shorter than the euploids in the GA variant only. These results suggest the presence of additional genetic factors for GA insensitivity on chromosomes of the groups 5 and 7 of hexaploid wheat. This corresponds with the localization of GA insensitive dwarfing genes on the homoeologous chromosomes 5R and 7R in diploid rye.
Barley Yellow Dwarf Virus Resistance in Triticum aestivum×Leymus angustus Hybrids
Authors: Plourde Ariane , Comeau A. , St‐Pierrf C. A.
Published: April 2006

The enzyme‐linked immunosorbent assay (ELISA) was used to determine the concentration of barley yellow dwarf virus (BYDV) in leaves of spring wheat Triticum aestivum L. cv. ‘Fukuhokomugi’, Leymus angustus (Trin.) Pilger (Altai wild rye) and their F1 hybrids inoculated at the 2‐ to 3‐leaf stage. The BYDV isolate “Cloutier” (serotype PAV) was used. The results showed that L. angustus confers immunity or strong resistance to the virus. Significant multiplication of the virus occurred in ‘Fukuhokomugi’ which expressed an intermediate level of tolerance to the disease under field conditions. The F1 haploid hybrids of ‘Fukuhokomugi’×L. angustus expressed a level of resistance almost equal to that of their wild parent, with a low concentration of virus appearing 16 days after inoculation and no more afterwards. The discovery of BYDV resistance in L. angustus and the expression of this character in the F1 hybrids provide new opportunities for the enlargement of the gene pool for BYDV resistance in wheat.
Diallel Analysis of the Inheritance of Partial Resistance to Downy Mildew in Peas
Authors: Stegmark R.
Published: April 2006

The aim of the investigation was to see if the partial resistance of three sister‐lines is determined by identical genes. The sister‐lines were selected from a cross between a susceptible line and a partially resistant line. These lines and the susceptible parent line were crossed in all directions. The downy‐mildew resistance of the different combinations was investigated in the F1, F3 and F4 generations. The resistance of the sister‐lines is not determined by the same genes. The moderate resistance of line X309 is recessive and might be determined by a single gene. The more resistant line X282 carry at least one resistance gene that shows dominance in crosses with X309. Line X311 carries, in addition to the resistance in X309, some resistance gene or genes with an intermediate effect.
Genetic Relationships Among Four Pepper Genotypes Resistant toPhytophthora capsici
Authors: Ortega R. Gil , PalazónEspañol C. , Zueco J. Cuartero
Published: April 2006

According to our previous investigations, resistance toPhytophthora capsidinCapsicum annuum genotypes, ‘Line 29’, ‘PI201232’, ‘PI201234’ and Serrano Criollo de Morelos 334 (‘SCM334’), seems to be controlled by three genes. In order to determine the genie relationships between these four sources of resistance, three experiments were conducted which included the four genotypes, their F1s, F2s, F3s and BC1generations together with the susceptible pepper genotype ‘Morron INI A 224’. Inoculations were made, when plants had 4—6 leaves, by irrigating the culture substrate with a zoospore suspension ofP. capsiciisolate ‘Bl’. Though the four genotypes showed percentages of resistance close to a 100%, none of them actually reached this level in the three experiments. ‘SCM334’ was the most resistant genotype, transmitting a high level of resistance to its F1, F2and BQ generations. ‘Line 29’ was more resistant than ‘PI201232’ and ‘PI201234’. However, the F1F2and BQ generations of these three lines showed similar degrees of resistance. The four genotypes seem to have one of the three genes postulated for their resistance in common. All genes displayed a similar level of resistance, except the specific genes of ‘SCM334’, the effect of which was slightly higher. Several working procedures are suggested for breeding programmes.
Polyploidy and Aneuploidy in the Tamarillo, Cyphomandra betacea (Cav.) Sendt. (Solanaceae)
Authors: Pringle G. J. , Murray B.
Published: April 2006

The successful induction of tetraploids in the tamarillo (Cyphomandra, betacea [Cav.] Sendt.) by the application of colchicine to the germinating seed is described. Chimeric and solid tetraploids were produced although the proportion of the chimeric types could be minimized by optimizing the treatment time. There were reciprocal differences in all interploidy crosses, with triploids being ineffective in crosses when used as the paternal parent. The analysis of aniline blue stained gynoecia showed that incompatibilities in interploidy crosses occurred largely at the post‐zygotic stage of the reproductive process. Triploids and aneuploids were produced from interploidy crosses. The features of some aneuploids were described. Most aneuploids produced were primary trisomics (2n = 2x + 1 = 25) but some had 26 chromosomes and two others were hyperpolyploids. Pollen fertility in these plants varied from 10% to 90%. Morphological traits did not differ between the aneuploids or between the aneuploids and diploids. Fruit and seed size in the aneuploids were comparable to those of the diploids and were thus suitable for potential commercial exploitation.
Correlated Response to Selection for Protein Yield in Oats After Three Cycles of Recurrent Selection
Authors: McFerson J. K. , Frey K. J.
Published: April 2006

Three oat (Avena saliva L.) populations (i.e., lines of descent), high grain yield (HG), high protein content (HP), and high protein yield per se (HGP), each developed by three cycles of S, recurrent selection, were evaluated for the effect of selection for groat‐protein yield upon other agronomic traits. Selections making up the HG line of descent had high protein yield primarily due to high grain yield, and those selected for HP had high protein yield due to both high protein content and high grain yield. Selection in HGP was on the basis of protein yield per se. Selection caused increases in bundle weight, harvest index, vegetative growth rate, and seed number in all lines of descent. Heading date, plant height, and seed weight were unaffected, whereas groat percentage and test weight were decreased in HP and HGP. Heritabilities were high for heading date, plant height, test weight, and seed weight, moderate for harvest index and bundle weight, and low for groat percentage. Genetic variability generally declined from CO to C3 for all traits.

Groat‐protein yield and amount of protein per groat increased in all lines of descent. In HG, the increase in groat weight was due primarily to increases in the nonprotein fraction, with groat‐protein content actually decreasing. In HGP, groat weight increased due to increases in protein and nonprotein fractions, and groat protein content remained constant. In HP, groat weight and amount of nonprotein per groat decreased, thus increasing groat‐protein content.

Three cycles of recurrent selection resulted in oat lines with groat‐protein yields significantly higher than the highest lines from CO. Utilization of index selection may be desirable to obtain populations of greater breeding value.
Amino‐Acid Resources in the Wild Progenitor of Wheats, Triticum dicoccoides, in Israel — Polymorphisms and Predictability by Ecology and Isozymes
Authors: Nevo E. , Beiles A.
Published: April 2006

Amino acid contents were measured in 109 genotypes from 22 populations of wild emmer wheat, Triticum dicoccoides, across its ecological range in Israel. Plants were grown outdoors on mesic Mr. Carmel, in a standardized environment, without irrigation and fertilization. T. dicoccoides was high in lysine and isoleucine contents as compared to six other species of wild wheats, but low in threonine and proline. Significant correlations were found among lysine and the other essential amino acids. Significant differences between Israeli populations of T. dicoccoides were found for isoleucine, methionine, leucine and threonine, but not for lysine, arginine, proline and glutamic acid. Significant differences between regions were only found in methionine. Ecological factors and allozyme markers appear to be good guidelines for predicting the ecogeographical location and allozymic constitution of specific elite amino acid genotypes, either singly or in combination. T. dicoccoides may be used in the future as a promising genetic resource for genetically improving the nutritional value of cultivated wheats.
Powdery Mildew Resistance Genes in 127 Northwest European Spring Barley Varieties
Authors: Jensen H. P. , Christensen E. , Jørgensen J. Helms
Published: April 2006

One hundred and twenty‐seven spring barley varieties grown in Denmark since 1979 were characterized for resistance genes using 30 powdery mildew isolates. The resistance genes are traced in the pedigrees to verify the results. Eleven named genes, 12 tentatively named genes/resistances and six unknown resistances were found. Resistance in many varieties was based on combinations of either known genes or of known and new factors. The following five new or relatively new resistance genes more or less effective against the present powdery mildew populations were detected: the ‘Mlo’ resistance conferred by the recessive mlo gene with the characteristic infection type 0/(4), ‘Ricardo’ and ‘Turkish’ sources having gene Mla3 in common and ‘Turkish’ with Ml(Tu2) in addition. In three varieties the new resistance Ml(IM9) was found in combination with different Mia alleles. Variety ‘Jarek’ has two new unidentified resistances.
Agronomic and Bioenergetic Consequences of Selection for High Groat‐Oil Content and High Protein Yield in Oat*
Authors: Schipper H. , Prey K. J.
Published: April 2006

Few studies have examined the effects of selection for high oil or protein content on the chemical composition of cereal seeds. This study was conducted to examine agronomic and bioenergetic consequences that result with changes in the chemical composition of groats of oat (Avena sativa L.). Oat lines with low and high groat‐oil content (GO) and with low and high groat‐protein content (GP) were chosen from each of five cycles of a recurrent selection program for increasing GO and from each of four cycles of a recurrent selection program for increasing protein yield via elevating GP, respectively. These lines were evaluated at three Iowa locations in 1988. The results indicated that GP was not significantly affected by selection for high GO and that GO significantly increased during selection for high protein yield via elevating GP. Both selection procedures resulted in oat lines with higher groat‐energy contents. A bioenergetic cost analysis showed that for GO in the oil population and GP in the protein population to be increased, additional photosynthate needed to be available.
Inheritance and Agronomic Performance of the Waxless Character in Brassica napus L.
Authors: Jianguo Mo , Wanqu Li , Jisheng Wang
Published: April 2006

A mutant of oilseed rape (B. napus L.) with waxless leaves was discovered in 1988. Three pairs of reciprocal crosses were made between the mutant (Wl) and 3 normal wax layered lines (Nwl). By the summer planting in Kunming and Wenjiang and the autumn planting in Wenjiang, it was confirmed that the Wl character is completely dominant to the normal opposite Nwl. Chi‐square tests revealed that the segregation ratios of Wl to Nwl among B1 and F2 plants fit to 1:1 and 3:1, respectively, i.e. the assumption of one gene pair. The yield of 12 hybrids, which were derived fom Wl and some Nwl lines, exceeded the check control ‘Zhong You 821’, a best cultivar in Chinese production by 19.31 % on the average. When the seedling had 3–4 leaves, both phenotypes can be accurately determined visually on the field. This material possesses potential value for studies of the genetics and breeding, as a prominent genetic marker in B. napus.
A Line with Four‐Seeded Pods Derived from an Interspecific Hybrid in Soybean
Authors: Gour V. K. , Mehta A. K. , Mehta S. K.
Published: April 2006

The cultivated soybean, Glycine max (L.) Merr., was crossed with its proposed wild progenitor, Glycine sofa (Seib. & Zucc.), to create useful genetic variability. A few plants with increased frequency of four‐seeded pods were identified in a segregating generation derived from this interspecific cross. One of them had about 45 percent four‐seeded pods per plant, whereas Glycine max and Glycine soja accessions used as parents in this study had only 8.0 and 5.1 per cent four‐seeded pods per plant, respectively. The established line finally had 32.5 per cent four‐seeded pods per plant, which is substantially higher as compared to either of the parents. Obviously, the genes which are responsible for this character are not expressed in the parental population.
Dosage Response of Rye Genes in a Wheat Background
Authors: Bittel D. C. , Fominaya A. , Jouve N. , Gustafson J. P.
Published: April 2006

Wheat (Triticum aestivum L.) breeders often utilize alien sources to supply new genetic variation to their breeding programs. However, the alien gene complexes have not always behaved as desired when placed into a wheat background. The introgressed genes of interest may be linked to undesirable genes, expressed at low levels or not at all. The short arm of rye (Secale cereale L.) chromosome one (1RS) contains many valuable genes for wheat improvement. In order to study rye gene response to varying copy number, wheat lines were constructed which contained zero, two or four doses of 1RS. The meiotic behavior of rye chromosome 1R, and wheat/rye translocation chromosomes, 1AL/1RS and 1BL/1RS was studied in the F1 hybrids between wheat lines carrying 1R or the translocation chromosomes. The IRS arm was transmitted at a very high frequency; 98 % of the F2 plants had at least one of the chromosomes with a IRS arm. In addition, 44 % of the F2 plants received at least one copy of the chromosomes from each parent. Analysis of the meiotic behavior of the IRS arm suggested that few euploid wheat gametes were formed. Therefore, most of the pollen must have contained IRS. It is unknown whether the lack of euploid wheat pollen could account for the high transmission frequency of the rye chromosomes. There may have been differential survival of the embryos receiving the rye chromosome as well.
Responses in Agronomic Traits Associated with Three Recurrent Selection Regimes for Groat‐Oil Content in Oat*
Authors: Schipper H. , Frey K. J.
Published: April 2006

Crop strains with high values for the selected trait but unacceptable agronomic characteristics are not useful as varieties. In this study, we determined whether selection for groat‐oil content in oat (Avena sativa L.) via three recurrent selection regimes caused associated changes in 10 agronomic traits. Random lines of each cycle of selection of each regime were evaluated in a replicated field experiment at two locations. Biomass, grain yield, groat yield, and test weight decreased in all three regimes. Seed weight and plant height decreased in two regimes, and groat fraction in one. Oil yield increased in two regimes and decreased in the other. Plants headed earlier in one and later in another regime over cycles of selection. No changes in harvest index occurred. Heritabilities and genetic variances were relatively high for all traits in each regime. Factor analysis of the phenotypic correlation matrices indicated that simultaneous increases in grain yield and in groat‐oil content are possible, that continuous selection for groat‐oil content decreases groat fraction and test weight, and that seed weight is strongly and negatively associated with groat‐oil content. A new recurrent selection regime for increasing groat‐oil content of oat that may overcome the negative responses of agronomic traits was proposed.
Mapping of Molecular Markers on Brassica B‐Genome Chromosomes Added to Brassica napus
Authors: Struss D. , Quiros C. F. , Röbbelen G.
Published: April 2006

Using interspecific hybridization among various Brassica species, B‐genome chromosomes from different sources of Brassica, i.e. B. nigra (BB, 2n = 18), B. carinata (BBCC), 2n = 34) and B. juncea (AABB, 2n = 36) were transferred into the Canadian variety ‘Andor’ of B. napus. Monosomic addition lines were selected (AACC + 1B, 2n = 39) by cytological control. For characterization of the alien chromosomes, series of isozymes, RFLPs and RAPD markers were employed. This permitted the identification of a total of 39 lines representing seven of the eight B‐genome chromosomes.
Production of Spontaneous Diploid Lines from Isolated Microspores Following Cryopreservation in Spring Rapeseed (Brassica napus L.)
Authors: Chen J. L. , Beversdorf W. D.
Published: April 2006

Cryopreservation of microspores provides a potentially powerful means for increasing percentage of spontaneous diploids in microspore‐derived populations in rapeseed (Brassica napus L.). This study was to investigate the production of spontaneous diploid lines in relation to steps of cryopreserving micro‐spores of two spring rapeseed breeding lines G‐231 and M3‐124. Microspores of both genotypes were isolated and subjected to Cryopreservation. The step of cooling process (before liquid nitrogen immersion) in a Cryopreservation protocol resulted in high percentages of spontaneous diploids in lines regenerated from frozen microspores in both genotypes. Liquid nitrogen immersion and subsequent thawing process had no influence on the percentage of spontaneous diploids. A linear relationship between percentage of spontaneous diploids and cooling temperatures was detected. The lowest cooling temperature of −40 °C yielded the highest percentages of spontaneous diploids (51.1 % in G‐231 and 47.7 % in M3‐124, respectively), which were more than doubled in comparison to those in the corresponding unfrozen controls. The current study indicated that cold treatment may be utilized to greatly enhance the percentage of spontaneous diploids in rapeseed breeding programs.
Phenotypic Variability for Bio‐Agronomical Traits in Berseem (Trifolium alexandrinum L.) Populations of the Meskawi Botanical Group
Authors: Martiniello P. , de Santis G. , Iannucci A.
Published: April 2006

The phenotypic variability and adaptability for bio‐agronomic traits in berseem populations (Trifolium alexandrinum L.), was evaluated. The number of genotypes was 32 (26 of southern Italy origin and 6 Egyptian). They were evaluated under field conditions for two years (1989–90) in Foggia (Italy) adopting different cutting regimes: at 7–8th inter‐nodes stem length, beginning of flowering, and no cutting. The genotypes of the Italian origin appeared to be better adapted when the cut was applied in the early stage of development, and more productive in seed yield. The Egyptian populations were most productive in forage in the later cuts and had a higher seed weight. The range of variation among the bio‐agronomical traits was higher when the cut was applied at early flowering. The traits with wider range of variation were: dry matter, plant height at cut, regrowth at the fourteenth day after cut, tiller density and seed yield. Considering a multiplicative selection index, 6 populations were well adapted and could be used as parents in breeding programs and in extended farm cultivation.
Methods for Detection and Estimation of Linkage between a Marker Locus and Quantitative Trait Loci
Authors: Zhang X. F. , Mosjidis J. A. , Hu Z. L.
Published: April 2006

Several methods have been proposed over the years to detect linkage between a marker gene and quantitative trait locus (QTL). Use of isozymes and restriction fragment length polymorphisms as genetic markers, has encouraged the development of new methods to detect linkage. We present three methods to detect linkage and two methods to measure recombination frequency (r). The three methods that detect linkage can be used when a single QTL or a tightly linked cluster of QTLs control the quantitative trait. The two methods that measure recombination frequency could not be used in the latter case because r would not be properly estimated. Procedures to calculate the additive and dominance gene effects of the QTL and the respective variances of these estimates were also presented.
Effectiveness of Twenty‐Four Barley Resistance Genes Against Powdery Mildew (Erysiphe graminis DC f. sp. hordei Em. Marchal) in Spain
Authors: Molina‐Cano J. L. , Montoya J. L. , Echarte J. , Royo C. , Serra J. , Marin‐Sanchez J. P.
Published: April 2006

Twenty‐four near‐isogenic barley lines, with a cv.‘Pallas’ background, carrying different mildew resistance genes were subjected in 1987, 1989 and 1990 to natural infection by the pathogen at several different and contrasting Spanish sites in order to study its virulence. The virulence genes proved to be geographically grouped into three regions: western (Valladolid), southern (Sevilla) and northern and northeastern (Navarra, Lleida and Girona). The mildew population of Lleida was more variable when compared with Navarra and Valladolid. Overall, the most effective resistance genes were: Ml‐a13 + Ml‐(Ru3), mlo and Ml‐(1402).
Reselection of a Pearl Millet Cultivar Utilizing Residual Variability for Downy Mildew Reaction*
Authors: Singh S. D. , Singh P. , Andrews D. J. , Talukdar B. S. , King S. B.
Published: April 2006

‘BJ 104’ was the most widely grown pearl millet hybrid in India until it became susceptible to downy mildew (DM) in 1984—85. Residual variability for resistance was found in both parental lines, 5141 B (maintainer of 5141 A) and J 104, and through four generations of pedigree selection under intense disease pressure in the DM nursery, two lines, IC‐MA841 (from 5141 B) and ICMP 84814 (from J 104), were selected resulting in a reconstituted DM resistant hybrid (‘ICMH 84814’) which was equal in yield to the original ‘BJ 104’. The reconstituted hybrid, though phenotypically similar, can be distinguished from “BJ 104” being slightly taller, flowers later, has heavier heads, and 1000‐seed weight, but tillers less.

A similar exercise was attempted on Tifton 23 B, the female parent of the first widely grown hybrid (‘HB 3’— the male parent was also J 104), but no variability for resistance to DM was found.
Development of Bruchid‐Resistant Mungbean Line Using Wild Mungbean Germplasm in Thailand
Authors: Tomooka N. , Lairungreang C. , Nakeeraks P. , Egawa Y. , Thavarasook C.
Published: April 2006

A mungbean (V. radiata) line (BC3F3 generation) which is resistant to two species of bruchid beetles (Callosobruchus chinensis and C. maculatus) was successfully developed in Thailand using a wild mungbean variety (V. radiata var. sublobata). One accession (TC1966) of wild mungbean was found to be completely resistant to C. chinensis and C. maculatus occurring at Chainat Field Crops Research Center in Thailand. The resistance was controlled by a single dominant gene (R). A breeding program to develop a bruchid‐resistant mungbean cultivar with good agronomic characters under the environmental conditions of Thailand was initiated in 1987.‘Chainat 60’ (‘CN60’), a recommended mungbean cultivar in Thailand, was crossed with TC1966 to incorporate the resistance gene. Agronomic characters of the hybrids were improved by recurrent backcrossing using ‘CN60’ as a pollen parent. Seed yield per plant, days to flowering, and seed size of the bruchid‐resistant BC3F2 population reached the level of ‘CN60’ after three consecutive backcrossings. Bruchid‐resistant line (BC3F3, R/R) was selected from individual BC3F2 plants.
Results in the Development of Alloplasmic Carrots (Daucus carota sativus Hoffm.)
Authors: Nothnagel Th.
Published: April 2006

Alloplasmic forms of the cultivated carrot, Daucus carota sativus Hoffm., were created by substitution backcrosses. The wild Daucus forms D. muricatus L., D. gingidium L., D. c. gummifer Hook, and D. c. libanotifolia Wiinst. were used as cytoplasm donors. In the first two backcross generations disturbances in fertility and plant physiology did not occur. The plants of the generations BC2F2 and BC2F3 look like cultivated carrots.

The alloplasmic forms were compared with cultivars for economic traits such as yield and yield components. The high content of total sugar in the alloplasmic forms was considerable. A new type of male sterility was found and described in a BC3F2 generation of the cross D. c. gummifer× D. c. sativus. Results of RFLP‐analyses of mt‐DNA and cp‐DNA were discussed.
Mitochondrial Genome Diversity within a Cultivar of Daucus carota (ssp. sativus) Revealed by Restriction Fragment Analysis of Single Plants
Authors: Steinborn R. , Weihe A. , Boerner T.
Published: April 2006

An effective method for the isolation and restriction fragment analysis of mitochondrial (mt) DNA from a few grams of plant material of Daucus carota sativus is presented. Employing radioactive end‐labelling of mtDNA restriction fragments, 12 single plants from a carrot cultivar, ‘Vitaminaja’, were investigated for mitochondrial genome diversity. Analyses revealed four different types of characteristic mtDNA restriction fragment patterns within the same cultivar. The mitochondrial genome diversity in the cultivar ‘Vitaminaja’ may result from non‐homogenous ancestor cytoplasms as well as from nuclear‐induced mtDNA rearrangements. Evaluation of intraspecific mitochondrial genome diversity may become an important issue in breeding programmes.
Pollen Characteristics and Genetics of Induced and Spontaneous Genetic Male‐Sterile Mutants in Rice
Authors: Hu Jinguo , Rutger J. N.
Published: April 2006

Pollen characteristics, inheritance and allelism of 23 genetic male‐sterile (ms) mutants of rice (Oryza sativa L.) were investigated. Ten of the mutants were induced by ethyl methane sulfonate, one induced by ethyleneimine, seven induced by gamma rays, one induced by streptomycin, one derived from tissue culture and three were spontaneous mutants found in the field. Four pollen abortion types were observed among these ms mutants: 3 no‐pollen (NP) type, 6 complete pollen abortion (CPA) type, 13 partial pollen abortion (PPA) type, and 1 stainable pollen abortion (SPA) type. Progeny tests over two years indicated that each of the mutants was inherited as a monogenic recessive. A partial diallel cross among the 23 ms mutants indicated that mutant E2 was allelic to G4, E5 was allelic to E9, N2 was allelic to N3, and that three other mutants, E3, G6 and T1, shared the same ms locus. Gene symbols ms‐46 (t) through ms‐63 (t) were assigned to these mutants.
Intergeneric Hybrids between Aegilops squarrosa and Secale cereale and their Meiotic Chromosome Behaviour
Authors: Kawakubo J. , Taira T.
Published: April 2006

Three hybrid plants with different combinations of D and R genomes were produced from crosses between Aegilops squarrosa (2×: and 4×) and Secale cereale (2× and 4×) using embryo culture. Production frequencies of mature hybrids, having the genomes DR, DDR and DDRR, were 2.0%, 5.2% and 2.2 %, respectively, of florets pollinated. Amphidiploids were obtained directly from the cross between tetraploid parents. The majority of their morphological features were intermediate between those of the parents but, as with rye, the rachis was tough. Diploid and triploid hybrids were completely seed‐sterile, whereas the amphidiploid had an average self‐fertility of 4.5 % with a range of 0 to 45 %.

The somatic chromosome numbers of diploids, triploids and amphidiploids were 2n = 14, 21 and 28, respectively. At meiotic metaphase I, the mean chromosome associations were 0.01 III + 0.26 II + 13.4 I in diploids, 6.96 II + 7.1 I in triploids, and 10.5 II + 7.9 I in amphidiploids. In diploids, pairing between D and R chromosomes was observed in the form of end‐to‐end types without chiasmata. Homologous pairing between D chromosomes was predominant in plants having two sets of D genomes. Amphidiploids showed a diploid‐like chromosome behaviour. Homoeologous pairing was not observed in either triploids or amphidiploids.
Effect of Karyotype on Somatic Embryogenesis from Immature Triticale (×Triticosecale Wittmack) Embryos
Authors: Immonen A. S. T.
Published: April 2006

To assess the tissue‐culture response of different karyotypes of spring triticales, immature embryo explants of 20 secondary triticales with a complete karyotype (complete rye genome with or without a 6D/6A substitution) or substituted karyotype (incomplete rye genome with a 2D/2R substitution), two primary triticales with octoploid and two with hexaploid karyotypes, were cultured on MS and on Kao medium supplemented with 2,4‐D. Complete triticales produced significantly more embryogenic callus than substituted types. Complete 6D/6A karyotypes showed the highest embryogenic response. Octoploid primary triticales showed high and uniform production of embryogenic callus on both media. These findings complement earlier results on the agronomic and quality differences between the karyotypes.
Identification of Rye Chromosomes Involved in Tolerance to Barley Yellow Dwarf Virus Disease in Wheat × Triticale Hybrids
Authors: Nkongolo K. K. , Armstrong K. C. , Comeau A. , Pierre C. A. St.
Published: April 2006

Common wheat × hexaploid triticale hybrids were produced and evaluated for tolerance to barley yellow dwarf virus disease (BYD). The BYD tolerance expression varied with wheat × triticale combination. The selection for BYD tolerance increased the recovery of tolerant genotypes in the next generations. Homozygous tolerant and susceptible lines were obtained in advanced generations. The rye chromosomes 1R, 2R, and 4R with 7R were transmitted as disomic or monosomic, disomic, and double disomic substitution to the late generations of ‘Musala’ (common wheat) ×‘Muskox 658’ (triticale), ‘Encruzilhada’ (common wheat) ×‘Nord Kivu’ (triticale) and ‘Encruzilhada’× 12th. International Triticale Screening Nursery 267 (12ITSN267) (triticale), respectively. A clear association was established between the 1R chromosome of the ‘Muskox 658’ triticale line and the tolerance to BYDV. Results suggest that the 2R chromosome may be involved in BYD tolerance of ‘Nord Kivu’ triticale line.
Identification of Rye Chromosome 1R Translocations and Substitutions in Hexaploid Wheats Using Storage Proteins as Genetic Markers
Authors: Gupta R. B. , Shepherd K. W.
Published: April 2006

Grain protein compositions of 106 advanced generation backcross lines from crosses involving ‘Amigo’ (1AL.1RS), ‘Aurora’, ‘Kavkaz’, ‘Skorospelka‐35’ and ‘Sunbird’ (all 1BL.1RS) and ‘Gabo’ 1DL.1RS parents and 152 cultivars with unknown pedigree were analysed by one‐dimensional SDS‐PAGE. Eighty seven backcross lines and 16 cultivars carried one or other of these translocations, 2 cultivars had a 1R (1B) substitution, whereas 5 backcross lines were found to be heterogeneous for the 1BL.1RS translocation. The translocation lines were easily identified by the presence of secalins (Sec‐1) controlled by rye chromosome arm IRS and a simultaneous loss of the gliadin (Gli‐1) and/or triticin (Tri‐1) protein bands controlled by the replaced wheat chromosome arm (1AS, 1BS or 1DS). Certain gliadins, showing no allelic variation among the genotypes analysed, were identified as markers for chromosome arms 1AS (Mr= 34 kd) and IBS (Mr= 42,33 kd). The whole chromosome substitutions 1R (1B) were recognized by scoring for the presence of Sec‐1 and HMW secalin bands, Sec‐3 (controlled by rye chromosome arm 1RL) and the absence of Gli‐B1 and HMW glutenin subunits, Glu‐B1 (controlled by wheat chromosome arm 1BL). The results have shown that protein electrophoresis provides a rapid and reliable technique for screening genotypes for these translocations and substitutions in a breeding programme.
Substituting Ability of Individual Barley Chromosomes for Wheat Chromosomes 1. Substitutions Involving Barley Chromosomes 1, 3 and 6
Authors: Islam A. K. M. R. , Shepherd K. W.
Published: April 2006

In order to determine the genetic relatedness of individual barley chromosomes to wheat chromosomes, ‘Betzes’ barley chromosomes 1, 3 and 6 were substituted for individual ‘Chinese Spring’ wheat chromosomes of homoeologous groups 7, 3 and 6, respectively. The substitution status of these lines has been confirmed using isozyme selective markers, chromosome pairing behaviour in F1 hybrids between the substitution lines and the appropriate double ditelocentric stocks of wheat, and hybridization of cDNA probes to the genomic DNA digests of these substitution lines. Each of the three barley chromosomes provided genetic compensation for the wheat chromosomes they replaced in the substitution plants. From the basis of this compensation with respect to plant vigour and fertility, barley chromosomes 1, 3 and 6 have been designated 7H, 3H and 6H.
Harvest Index and Spike Index in Crosses between Wheat Genotypes with Different Spike Architecture
Authors: Denčić S. , Borojević S.
Published: April 2006

Crosses between vulgare wheat genotypes with different spike architecture were examined for total biomass per plant, grain mass per plant, and harvest index. The genotypes with branched spikes (turgidum type) and tetrastichon spikes were equal or superior to those with normal spikes in total biomass per plant but inferior in grain mass per plant. Consequently, they had significantly lower harvest indices. In the F1 and F2 generation, high heterosis for total biomass per plant occurred in all crosses between the genotypes with branched and normal spikes. There was heterosis for grain mass per spike in most crosses, but it was not as high as for total biomass.

This investigation confirmed earlier findings that genetic changes towards the branched or the tetrastichon spike do not increase the potential for grain yield. Since, however, the crosses between the genotypes with branched and normal spikes showed high heterosis for grain mass per plant, lines with highly fertile but normal spikes may be expected in the segregating generations as a result of a genetic change in sink capacity. The genotypes with branched and tetrastichon spikes produced higher biomass per spike but lower spike index than the genotypes with normal spike. This may be an indication that the increase in vegetative area of the spike does not necessarily have a positive effect on grain mass per spike.
The Inheritance of Components of Fruiting Season, Yield and Vigour in Short‐Day Strawberries and the Relationship between Pistillate Flowers and Flowering Time
Authors: Simpson D. W.
Published: April 2006

The study was designed to provide information on the inheritance of the fruiting period in strawberries and to ascertain whether pistillate seedlings differed in any important respects from their hermaphrodite sibs. Seven short‐day genotypes, covering the full range of outdour cropping seasons in the UK, were crossed in a half‐diallel without selfs and the seedlings grown in the field. Six plant characters, components of fruiting season, yield and vigour, were analysed and each one was found to be heritable with the additive genetic component contributing more towards the overall genetic variance than the non‐additive component. There was more variation for flowering time than for maturation time but both characters are important when breeding for an extended season.

The pistillate cultivar‘Pandora’ contributed both the latest flowering and slowest fruit maturation to its progeny and an association was found between late flowering and pistillate flowers, suggesting a possible linkage. This will limit the usefulness of‘Pandora’ as a parent when breeding late‐fruiting strawberries.
Variability of Yield Characters and Selection in Solanum ladniatum Ait.
Authors: Vocel Hermine , Jatisatienr A. , Horn W.
Published: April 2006

The steroid bearing medicinal plant, S. laciniatum, was bred for high solasodine yield for commercial cultivation in Thailand.

Starting materials for breeding consisted of seven populations of different origin. Variability among these populations was examined using an unselected control population cultivated over three years. Additive and dominance variance were estimated from a polycross and diallel mating design.

Significant genotypic variability was found for solasodine concentration, height of the plants, and total shoot length, promising successful selection for the most important yield characters.

Additive variance and heritability in the narrow sense were low for all yield characters, due to previous selection of the parental plants used for the polycross and diallel mating.

No dominance effects could be found for any of the characters. In conclusion, breeding S. laciniatum for quantitative yield characters by selection will be superior to hybrid breeding.

As a result of selection, significant increases in the most important yield characters in the offspring of selected populations were obtained.
Genetics of New Crop Genus Limnanthes I. Five Morphological Marker Loci in L. alba × L. gracilis Progenies
Authors: Dole J. A. , Jain S. K.
Published: April 2006

New crop development often depends on a few essential traits such as nonshattering of seed at maturity and pollination control. In order to domesticate Limnanthes alba (meadowfoam), as a source of industrial oil, we performed genetic analysis of crosses between L. alba and its closest relative Limnanthes gracilis var. gracilis which shows higher selfing ability and nutlet abscission. Differences in pubescence, nutlet abscission, and seedling pigmentation were each found to be governed primarily by a single locus; two interacting loci appeared to control capsule dehiscence. Segregation distortion was detected for pigmentation in F2 and F3 populations, and for pubescence in several F3 families. Loci controlling pubescence, nutlet abscission, and capsule dehiscence resided in a single linkage block which assorted independently of the locus controlling pigmentation.
The Effect of Sugars and Growth Regulators on Embryoid Formation and Plant Regeneration from Barley Anther Culture
Authors: Cai Q. , Szarejko I. , Polok K. , Maluszvnski M.
Published: April 2006

The influence of carbon source and growth regulator composition in induction medium on anther culture response was investigated using spring barley genotypes. Anthers were cultured on BAC3, Ficoll‐containing medium, supplemented with one of the following carbohydrates: sucrose, maltose, cellobiosc and melibiose (6 % w/v). The use of either maltose or cellobiose resulted in a significantly higher anther response, calli and/or embryoid production and green plant regeneration compared to the incubation of anthers on a medium containing sucrose. Contrary to these results, the replacement of sucrose by melibiose in BAO medium, drastically reduced the efficiency of anther culture. As an average for the three genotypes tested, the frequency of green plants per 100 anthers plated was 9‐ to 22‐fold higher on medium supplemented with sucrose or cellobiose than on medium containing melibiose as a sole carbohydrate.

Among the growth regulators tested, the combination of auxin NAA (2 mg/l) and cytokinin BAP (1 mg/1) performed much better than the employment of auxin 2,4‐D combined either with zeatin riboside or BAP as cytokinins. The beneficial effect of medium supplemented with NAA and BAP was associated with better embryoid formation compared to the other growth regulator combinations tested. The hormone‐free combination gave a similar anther response and production of calli as any medium supplemented with growth regulators, but the regeneration capacity of calli produced on hormone‐free medium was much lower, resulting in the drastic reduction of the number of both total and green regenerants.
Resistance to Polymyxa betae in Beta Species of the Section Procumbentes, in Hybrids with B. vulgaris and in Monosomic Chromosome Additions of B. procumbens in B. vulgaris
Authors: Paul H. , Henken B. , Bock Th. S. M. de , Lange W.
Published: April 2006

Resistance to Polymyxa betae was studied in Beta species of the section Procumbentes, in hybrids of B. vulgaris with B. procumbens or B. patellaris, and in monosomic additions of chromosomes of B. procumbens in B. vulgaris. In all experiments P. betae infested with beet necrotic yellow vein virus (BNYVV) was used. This virus causes rhizomania in sugar beet, and the effect of vector resistance was studied by measuring virus concentrations. Cystosori of P. betae were not found in the wild species and the hybrids. Virus concentrations in these plants were low, and in half the number of plants the virus could not be detected. Results of experiments with the monosomic additions indicate, that resistance to P. betae in B. procumbens is located on chromosomes 4 and 8. Some cystosori were present in these addition types, while cystosori were abundantly present in other addition types and all sib‐plants. Virus concentrations in the addition types 4 and 8 were lower than in their sib‐plants, but in almost all plants the virus could be detected. A significant correlation (r = 0.91; P < 0.05) between average numbers of cystosori and average virus concentrations was found when addition families of type 8 were tested together with B. procumbens and B. vulgaris cv. ‘Regina’.