bluuebunny/crossref_metadata_2025_split huggingface dataset:
Impact of resistant melon cultivars on Sphaerotheca fuliginea
Authors: Hosoya K. , Kuzuya M. , Murakami T. , Kato K. , Narisawa K. , Ezura H. 
Published: March 2003

AbstractEffects of the resistant cultivars of melon on the powdery mildew fungus, Sphaerotheca fuliginea, were investigated in a melon‐growing area of Japan. Powdery mildew fungi were isolated from four melon cultivars (‘HN21’, ‘Quincy’, ‘Earl's Knight Natsu 2’ and ‘Earl's Miyabi Natsu 2′) which are resistant to different races of S. fuliginea.‘HN21’is resistant to races 1 and N1,‘Quincy’ and ‘Earl's Knight Natsu 2’are resistant to races 1 and N2, and ‘Earl's Miyabi Natsu 2’is resistant to races 1, N1 and N2. All 155 strains isolated from ‘HN21’were identified as race N2. Seventy out of 81 strains isolated from ‘Quincy’ and ‘Earl's Knight Natsu 2’were identified as race N1, while other strains were identified as races 1, 2US, N2 and N3. Nineteen out of 29 strains isolated from ‘Earl's Miyabi Natsu 2’were identified as race N3, while other strains were identified as races 10, 2US, N1 and N4. These results suggest that, although the resistant cultivars are extremely effective for protecting the plants from their respective races, a race succession rapidly takes place, even in a small area, and other minor races become predominant.
Molecular mapping and gene action of Scm1 and Scm2, two major QTL contributing to SCMV resistance in maize
Authors: Duble C. M. , Melchinger A. E. , Kuntze L. , Stork A. , Lubberstedt T. 
Published: March 2003

AbstractSugarcane mosaic virus (SCMV) is one of the most important virus diseases of maize in Europe. In this study, the gene action at two major quantitative trait loci (QTL) affecting resistance to SCMV in maize was mapped and characterized. A total of 121 F3 lines from cross F7 (susceptible) × FAP1360A (resistant) were evaluated for SCMV resistance in replicated field trials across two environments under artificial inoculation at seven scoring dates. The genotypic variance was always highly significant and heritability increased up to 0.92 for later scoring dates. The method of composite interval mapping was employed for QTL mapping using four simple sequence repeat (SSR) markers flanking two regions identified in a previous study with cross D145 × D32. The presence of two QTL for SCMV resistance, one on chromosome 6 (Scml region) and one on chromosome 2 (Scm2 region), was confirmed. These two QTL together explained between 15% (first score) and 62% (final score) of the phenotypic variance at various stages of plant development. Gene action was additive for the Scm1 region but completely dominant for the Scm2 region. Comparison of results of this study with those obtained for cross D145 × D32 suggested that the resistance alleles in the two populations are identical for the Scm1 region but different for the Scm2 region.
Crosses between cultivars and tissue culture‐selected plants for salt resistance improvement in rice,Oryza sativa
Authors: Zhu G. Y. , Kinet J. ‐M. , Bertin P. , Bouharmont J. , Lutt S. 
Published: March 2003

AbstractSeveral R2somaclonal families were derived from plants regenerated from a salt‐resistant callus of the salt‐sensitive rice cultivar ‘I Kong Pao’ (IKP). The family R2‐1‐23, in the presence of NaCl exhibited higher yield performances than the initial cultivar. This improvement in salinity resistance, however, was not transmitted to following generations; despite a higher number of spikelets per plant, family R3‐1‐23 did not perform better than the initial cultivar because of a very low seed set. This somaclonal family, its initial being the cultivar IKP, the breeding line IR31785 (extremely salt‐sensitive) and the cultivar ‘Aiwu’ (moderately salt‐resistant), were used as parents for production ofhybrids. Four crosses, IKP×R3‐1‐23, IR31785 ×R3‐1‐23, IR31785× IKP and IKP ×‘Aiwu’, were performed. Most of the F1hybrids cultivated in the absence of salt exhibited increased performances compared with the mid‐parent, suggesting an heterosis effect for yield‐related parameters. F2populations were screened for salinity resistance and a clear improvement for yield in stress conditions was recorded for populations derived from IK×R3‐1‐23, IR31785×R3‐1‐23 and IR31785×IKP, although the mean level of increase over the mid‐parent (RIMP) varied depending on the population, the presence or absence of stress, and the quantified parameters. The results are discussed in relation to the usefulness of in vitro selection for obtaining interesting somaclonal variants useful to be integrated in classical breeding programmes for salinity resistance in rice.
Genetic variation for pod wall proportion in Lupinus albus
Authors: Lagunes‐Espinoza L. C. , Huyghe C. , Papineau J. 
Published: March 2003

AbstractThe proportion of pod walls is considered as a potential selection criterion for seed yield in white lupin. It has a negative and highly significant phenotypic relationship with the seed yield and the genetic correlation between both traits is negative and high. The present study over 2 years (1996 and 1998) evaluated the genetic variation of proportion of pod walls in a set of 325 spring‐sown white lupin accessions originating from 17 different countries. Wide ranges of variation for this trait and other pod components were observed. This variation has a geographical distribution. Egyptian ecotypes had the lowest proportions of pod walls while the Greek and Italian ecotypes had the highest. The between‐country range of variation for the proportion of pod walls, was lower than the within‐country range (0.25‐0.31 and 0.21‐0.36, respectively) and the within‐country variance accounted for 51% of the total genetic variation. The broad‐sense heritabilities of pod wall proportion and proportion of pod walls for one full locule were moderate (0.44 and 0.57, respectively), which indicates that the proportion of pod walls can be used in breeding.
Effects of the two most common Wx alleles on different genetic backgrounds in rice
Authors: Mikami I. , Dung L.‐V. , Hirano H. ‐Y. , Sano Y. 
Published: March 2003

Abstract Wxa and Wxb are the most common alleles of the Wx gene in Asian cultivated rice. The difference between them is responsible for differences in the levels of the Wx gene product in the endosperm, as well as in amylose content, which is an important determinant of the quality of edible rice. Since Indica rice mostly carries the Wxa allele, we introduced the Wxb allele into Indica‐type rice (IR36) from a Japonica‐type rice (T65) by repeated backcrossing. In the near‐isogenic line (IR36 Wxb), the level of the Wx gene product was reduced and, as expected, the level of amylose. However, IR36Wxb had a lower amylose content than the recurrent parent of T65 with the Wxb allele. The results suggest that the Indica (IR36) background might lower the amylose content more than the Japonica (T65) background when the Wx allele is the same. The possible importance of modifiers that regulate expression of the Wx gene is also discussed in relation to improvements in the grain quality of rice.
Variation in root penetration ability, osmotic adjustment and dehydration tolerance among accessions of rice adapted to rainfed lowland and upland ecosystems
Authors: Chandra Babu R. , Shashidhar H. E. , Lilley J. M. , Thanh N. D. , Ray J. D. , Sadasivam S. , Sarkarung S. , O'Toole J. C. , Nguyen H. T. 
Published: March 2003

AbstractDrought is the major constraint limiting rainfed rice production. The ability of rice roots to penetrate compacted soils and therefore to increase water extraction capacity, osmotic adjustment and dehydration tolerance of leaves enables the plant to tolerate drought. Experiments were conducted to determine the extent of genetic variation in root penetration index, osmotic adjustment and dehydration tolerance among indica accessions adapted to rainfed lowlands as well as traditional varieties from rainfed uplands. Root penetration index was evaluated in a system using wax–petrolatum layers to simulate soil compaction. Osmotic adjustment and dehydration tolerance were studied under slow development of water stress. Substantial genetic variation was found for root penetration index, osmotic adjustment and dehydration tolerance among indica ecotypes from lowlands, and the study of several traditional varieties from uplands showed variation in root penetration index and related root traits. An indica accession, IR58821‐23‐B‐1‐2‐1 had a high root penetration index of 0.38. The accessions, IR61079‐33‐1‐2‐2‐3, IR62266‐42‐6‐2 and IR63919‐38‐B‐1 had high osmotic adjustment capacities (1.91, 1.90 and 1.78 MPa, respectively); IR61079‐33‐1‐2‐2‐3 also had high dehydration tolerance. Good osmotic adjustment and dehydration tolerance were associated with poor root system. The traditional varieties ‘Kallurundaikar’ and ‘Norungan’ had higher root penetration indices (0.46 and 0.43, respectively), than even the japonica accessions. The study identified indica accessions and traditional varieties with superior root‐ and shoot‐related drought resistance traits that could be used in breeding for drought resistance in rice.
Influence of genotype and culture medium on callus formation and plant regeneration from immature embryos of Triticum turgidum Desf. cultivars
Authors: González J. M. , Friero E. , Jouve N. 
Published: March 2003

AbstractTwelve durum wheat cultivars were evaluated for their response to in vitro tissue culture. Zygotic immature embryos were used to induce callus formation using four different Murashige and Skoog‐based media. Each contained 9.05 μM 2,4‐dichlorophenoxy acetic acid but differed in their carbon source (sucrose or maltose) and the presence of NaCl (0 mM or 40 mM). The influence of both genotype and medium on the type and percentage of callus produced was observed. Calli were either compact and frequently embryogenic, or soft and watery. Percentages ranged from 54 to 100%, depending upon genotype and induction medium. All calli were then plated on a regeneration medium containing 20 g/l sucrose, 2.68 μM 1‐naphthaleneacetic acid and 2.22 μ 6‐benzylaminopurine. The regeneration of plantlets was higher from compact than from soft calli, with a strong dependence on genotype and type of induction medium used. MSm induction medium (30 g/l maltose) and MS40s (30 g/l sucrose plus 40 mM NaCl) were best for inducing compact calli, and gave the highest proportion of regenerated plants. The in vitro response (number of total shoots from a compact callus/number of embryos plated) was higher for immature embryos of ‘Baztan’, ‘Bradano’ and ‘Don Pedro’. These cultivars are a good starting material for experiments involving transformation of calli from zygotic immature embryos.
A cytogenetic study of bilateral sexual polyploidization in cassava (Manihot esculenta Crantz)
Authors: Ogburia M. N. , Yabuya T. , Adachi T. 
Published: March 2003

AbstractMicrosporogenesis and megasporogenesis were cytogenetically and histologically analysed in three cassava clones:‘Rayong 1′,‘Rayong 60′,‘M. mga’ and two hybrid lines,‘OMR 3641‐1’ and ‘OMR 3641‐1’ to elucidate the evolution of sexual polyploids in cassava. At telophase II, formation of 17‐21 micronuclei per pollen cell plate was observed in 16 out of 351 cell plates in ‘M. mga’. Micronuclei were observed at low (0.3‐2.3%) frequencies, at the sporad stage in all clones. Monads, dyads, triads and tetrads, which are established sources of high ploidy levels were observed at low (2.6%) and high (22.2%) frequencies. Megasporogenesis in ‘Rayong 1’ and ‘Rayong 60’ showed a lack of second meiotic divisions after a successful first division that resulted in partly unreduced embryo sacs with 2n eggs, suggesting another unrecognized and, as yet, unreported source of sexual polyploid formation in cassava. Meiotic abnormalities during microsporogenesis and megasporogenesis are implicated as being responsible for the formation of mixoploids (triploids and tetraploids) in cassava breeding programmes. A cytogenetic mechanism resulting in bilateral sexual polyploids through different gametic fertilization pathways in cassava is suggested and its role in breeding is briefly discussed.
RAPD‐based detection of genomic instability in soybean plants derived from somatic embryogenesis
Authors: Gesteira A. S. , Otoni W. C. , Barros E. G. , Moreira M. A. 
Published: March 2003

AbstractRandom amplified polymorphic DNA (RAPD) markers were used to evaluate genetic stability of regenerants of soybean plants obtained through somatic embryogenesis using 180 μM 2,4‐dichloro‐phenoxy acetic acid. Twenty primers were used to screen 44 regenerants from the cultivar ‘Spring’ and 28 from the cultivar ‘CAC‐1’. Three primers were polymorphic for two of the ‘Spring’‐derived regenerants, with a somaclonal frequency of 4.5%. Four primers were polymorphic for the ‘CAC’‐l‐derived regenerant, with a somaclonal frequency of 3.57%. The results indicate the usefulness of RAPD markers to detect genetic instability in soybean primary regenerant plants derived from somatic embryogenesis, and as a certification tool for monitoring genetic stability during the regeneration process.
Inheritance of reduced linolenic acid content in the Ethiopian mustard mutant N2‐4961
Authors: Velasco L. , Fernández‐Martínez J. M. , Haro A. De 
Published: March 2003

AbstractThe zero erucic acid Ethiopian mustard lines developed so far are characterized by an exceptionally high linolenic acid content in the seed oil. The mutant line N2‐4961, expressing low linolenic acid content in a high erucic acid background, was developed through chemical mutagenesis. The objective of this research was to study the inheritance of low linolenic acid content in this mutant. Line N2‐4961 was reciprocally crossed with its parent line C‐101 and the linolenic acid content of the reciprocal F1, F2 and BC1 generations was studied. No maternal, cytoplasmic or dominance effects were detected in the analysis of F1 seeds and F1 plants from reciprocal crosses. Linolenic acid content segregated in 1: 2: 1 ratios in all the F2 populations studied, suggesting monogenic inheritance. This was confirmed with the analysis of the reciprocal backcross generation. The simple inheritance of low linolenic acid content in N2‐4961 will facilitate the transference of this trait to zero erucic acid lines of Ethiopian mustard.
Genetic analysis of total glucosinolate in crosses involving a high glucosinolate Indian variety and a low glucosinolate line of Brassica juncea
Authors: Sodhi Y. S. , Mukhopadhyay A. , Arumugam N. , Verma J. K. , Gupta V. , Pental D. , Pradhan A. K. 
Published: March 2003

AbstractAnalysis of the glucosinolate content and composition by high‐pressure liquid chromatography indicated that varieties of Brassica juncea bred and grown in India have a high glucosinolate content characterized by the presence of 2‐propenyl (allyl) and 3‐butenyl as the major and 4‐pentenyl as the minor fractions. In contrast, the B. juncea germplasm from other countries is characterized by the presence of 2‐propenyl as the major glucosinolate fraction, trace amounts of 3‐butenyl and a total lack of the 4‐pentenyl types. In order to transfer the low glucosinolate trait to Indian B. juncea, the inheritance of total glucosinolates was investigated using doubled haploid (DH) populations derived from F1 (DH1) and BC1 (BC1DH) of a cross between ‘Varuna’ (the most widely cultivated high glucosinolate variety of India) and ‘Heera’ (a non‐allyl type low glucosinolate line). A total of 752 DH1 and 1263 BC1DH gave rise to seven and 11 low glucosinolate (containing less than 18 μmol/g seed) individuals, respectively. On the basis of the frequency of the low glucosinolate individuals, the total glucosinolate was found to be under the control of seven genes. There was presence of both allyl and non‐allyl types in DH1 and BC1DH low‐glucosinolate individuals and absence of 3‐butenyl glucosinolate in some of the BC1DH low glucosinolate individuals, indicating segregation for these fractions in the population. The size of the segregating DH population proved to be crucial for precise determination of the number of genes controlling the trait. Because of the large number of genes involved, incorporation of low glucosinolate trait in Indian B. juncea should be approached through doubled haploid (DH) breeding.
Microsatellite marker for yellow rust resistance gene Yr5 in wheat introgressed from spelt wheat
Authors: Sun Q. , Wei Y. , Ni Z. , Xie C. , Yang T. 
Published: March 2003

AbstractYellow rust of wheat caused by Puccinia striiformis f sp. tritici has been periodically epidemic and severely damaged wheat production in China and throughout the world. Breeding for resistant cultivars has been proved to be an effective way to resolve the problem. A yellow rust resistance gene, Yr5, derived from Triticum spelta shows immunity or high resistance to the most popular isolates Tiaozhong 30 and 31 in China. Establishment of DNA markers for the Yr5 gene will facilitate marker‐assisted selection and gene pyramiding in the breeding programme. Since the Yr5 gene was cytologically located on the long arm of chromosome 2B, By33, the donor of Yr5, was crossed and backcrossed with the susceptible line 441, and BC3F2 and BC3F3 segregating populations were screened for polymorphism by using 11 microsatellite primers mapped on chromosome 2B. A marker, Xgwm501‐195 bp/160 bp, was found to be linked to Yr5, with a genetic distance of 10.5‐13.3 cM.
Waxy proteins in diploid, tetraploid and hexaploid wheats
Authors: Urbano M. , Margiotta B. , Colaprico G. , Lafiandra D. 
Published: March 2003

AbstractElectrophoretic analyses of waxy proteins, encoded by genes present at the Wx‐1 loci, present in several cultivars and accessions of hexaploid wheat, Triticum aestivum, have permitted the detection of null alleles at the Wx‐B1 and Wx‐D1 loci. Polymorphism at the Wx‐A1 and Wx‐B1 loci was also investigated in several accessions of tetraploid wheats, Triticum durum, Triticum dicoccoides and Triticum timopheevi, and in diploid species, Triticum urartu, Triticum boeoticum and Triticum monococcum. One null allele at the Wx‐A1 locus and three polymorphic alleles at Wx‐B1 locus were detected in T. durum; a new allele at one of the two waxy loci was identified in the tetraploid wheat T. timopheevi; no polymorphism was detected in diploid species. Polymerase chain reaction techniques made possible the detection of further polymorphism existing at the Wx‐1 loci and the reason for the lack of expression of the null genotypes to be investigated. The null forms detected at each locus have been used to produce complete sets of partial and total waxy lines in durum and bread wheat.
Molecular and physical mapping of genes affecting awning in wheat
Authors: Sourdille P. , Cadalen T. , Gay G. , Gill B. , Bernard M. 
Published: March 2003

AbstractQuantitative trait loci (QTL) for three traits related to awning (awn length at the base, the middle and the top of the ear) in wheat were mapped in a doubled‐haploid line (DH) population derived from the cross between the cultivars ‘Courtot’ (awned) and ‘Chinese Spring’ (awnless) and grown in Clermont‐Ferrand, France, under natural field conditions. A molecular marker linkage map of this cross that was previously constructed based on 187 DH lines and 550 markers was used for the QTL mapping. The genome was well covered (more than 95%) and a set of anchor loci regularly spaced (one marker every 20.8 cM) was chosen for marker regression analysis. For each trait, only two consistent QTL were identified with individual effects ranging from 8.5 to 45.9% of the total phenotypic variation. These two QTL cosegregated with the genes Hd on chromosome 4A and B2 on chromosome 6B, which are known to inhibit awning. The results were confirmed using ‘Chinese Spring’ deletion lines of these two chromosomes, which have awned spikes, while ‘Chinese Spring’ is usually awnless. No quantitative trait locus was detected on chromosome 5A where the B1 awn‐inhibitor gene is located, suggesting that both ‘Courtot’ and ‘Chinese Spring’ have the same allelic constitution at this locus. The occurrence of awned speltoid spikes on the deletion lines of this chromosome suggests that ‘Chinese Spring’ and ‘Courtot’ have the dominant B1 allele, indicating that B1 alone has insufficient effect to induce complete awn inhibition.
Chromosome doubling of haploid maize seedlings using nitrous oxide gas at the flower primordial stage
Authors: Kato A. , Geiger H. H. 
Published: March 2003

AbstractIn maize, inbred lines are used for the production of hybrid varieties. Corn breeders and researchers have considered using haploids to develop inbred lines; however, this procedure has not been practically applied because of the inefficiency of chromosome doubling of maize haploid seedlings. In this report, a procedure has been developed to overcome this difficulty. Maize haploid seedlings obtained from eight different genotypes were treated with nitrous oxide gas (2 days at 600 kPa). Treatment at the six‐leaf stage (flower primordia formation stage) significantly increased the occurrence of fertile sectors on both tassels and ears so that approximately half (44%) of the treated haploids produced kernels after self‐pollination. In the control, only 11% of haploids produced selfed kernels owing to spontaneous chromosome doubling. A strong genotypic effect on the occurrence of fertile sectors after the treatment was observed. This procedure can be used for inbred line development in maize breeding programmes.
Development of self‐incompatibleBrassica napus:(I) introgression of S‐alleles fromBrassica oleraceathrough interspecific hybridization
Authors: RIPLEY V. L. , BEVERSDORF W. D. 
Published: March 2003

AbstractCultivars inBrassica napusvar.oleifera, a self‐pollinating, self‐compatible species, have traditionally been developed as open‐pollinated lines or populations. Significant yield gains in this species have been realized through the exploitation of heterosis. Commercial hybrid production has been possible as a result of the development of a number of pollination control systems. Self‐incompatibility was transferred fromB. oleraceavar.italicatoB. napusvar.oleiferathrough interspecific hybridization. The response to interspecific pollination, as measured by pod elongation and initial stages of ovule development, was genotype dependent, and two highly responsiveB. napusgenotypes were identified. Embryo rescue was used to produce the interspecific hybrids. Isoelectric focusing of stigma proteins was used to identify S‐alleles in the interspecific hybrids to facilitate backcrossing. Segregation of the S‐locus through a series of back‐crosses toB. napuswas complicated by aneuploidy; however, the S‐locus was found to segregate as a single gene. Usefulness ofB. oleraceaas a source of S‐alleles for pollination control inB. napusis discussed.