摘要:

AbstractResistance of wheat toFusariumhead blight caused byFusarium graminearumandF. culmorumwas identified in natural epidemics in 1985 and 1987 as well after artificial inoculations (1983–1988 and 1984–1987). Out of 25 genotypes tested, five were identified with no significant difference in head blight scores, but differing significantly in yield after artificial inoculation, i.e. tolerance differences were detected at different resistance levels. Some genotypes that were similar in yield or head blight scores differed in seed infection severity. Genotypes with awns were more susceptible to head blight when tested under natural epidemic condition in the field; but this trait did not influence head blight severity in artificial inoculations. Dwarf genotypes were more severely infected by head blight than tall genotypes under natural conditions, but genotypes of different plant height classes were similarly susceptible after artificial inoculations. In the early generations of a breeding programme resistance measured by visual evaluation of artificial inoculation is the most important way to screen. If selection of dwarf and awned genotypes cannot be avoided, the higher susceptibility caused by awns and dwarfness under natural epidemic conditions can be decreased by a higher level of physiological resistance, as variability in physiological resistance is available. In later generations, traits like percentage of seed infection or tolerance can be identified by additionally measuring yield reduction. Stability of disease reaction appears to be connected with resistance level, the most resistant genotypes are the most stable, and the most susceptible ones tend to have more unstable reactions in different epidemic conditi

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1995.tb00816.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractThe winter‐wheat line RE714, resulting from an intergeneric cross betweenAegilops squarrosaandTriticum dicoccum, and implying a sister line of ‘Roazon’ (VM4) in its genealogy, was obtained in order to increase the genetic diversity for disease resistance. The aim of this study was to identify and characterize the powdery‐mildew‐resistance gene(s) present in this line at the seedling stage on detached leaves. The comparison of the reaction of the RE714 line and of differential hosts to 24Erysiphe graminis.f.sp.triticiisolates indicated that onlyPm4a, Pm4band/orMlargenes could be present and that a new resistance factor, different from all known mildew‐resistance genes, was present in this line. The powdery‐mildew reactions of segregating F2populations produced evidence that RE714 carries the Pm4b allelic form and a recessive new resistance gene, tentatively designatedmlre.WhileAe. squarrosawas resistant to most isolates,T. dicoccumwas specifically attacked by REV 14‐virulent isolates and was therefore assumed to be the donor of mire. The VM4 parent was confirmed

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1995.tb00817.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractGrain yield and some of its physiological determinants were analysed in a field study conducted over two growing seasons with standard‐height (SH), semi‐dwarf (SD) and dwarf (DD) isogenic lines of a spring wheat sown at recommended and delayed dates. The objective was to test whether the action ofRht1 andRht2 alleles in improving grain yield depended upon sowing date.As expected, the dwarfing genes significantly reduced plant height in both sowings and growing seasons. There was a tendency for the SD line to produce more biomass than the SH and DD lines, although the differences were mostly not significant. Harvest index was linearly and negatively related to plant height. Consequently, the SD and SH line showed the highest and lowest grain yields in all environments. The optimum height for grain yield was estimated to bec.70 cm, and this value was not affected by sowing date. Lines carryingRht1 and/orRht2 alleles always showed more grains/m2(owing to an increased number of grains per spike and spikes/m2) than the SH line. Conversely, average grain weight was negatively associated with the number of grains/m2. Because the slope of this negative relationship was smaller (less negative) than that representing complete compensation, the relationship between grain yield and number of grains/m2was hyperbolic. Although these relationships are frequently regarded as a reflection of increased competition among grains when the number of grains/m2is increased owing to the use of semi‐dwarf genes, two alternative hypotheses are analysed and disc

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1995.tb00818.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractThe vast majority of the world's acreage of semi‐dwarf wheat varieties is at present cultivated with varieties carrying one of two genetically similar dwarfing genes,Rht1 andRht2, derived from the Japanese variety ‘Norin 10’. Near‐isogenic lines have been developed and tested to determine the breeding potential of an allelic variant ofRht1, designated Rht1(B.dw).Following its introduction into four varietal backgrounds,Rht1 (B. dw) was seen to reduce height by around 25%, to increase the number of grains setting in spikelets and ears by around 20%, to reduce grain weight by 10%, and to increase yields of plants grown under spaced or drilled conditions by about 8%.When compared to the commercially utilizedRht1 allele, as near isogenic lines in a ‘Mercia’ varietal background,Rht1 (B. dw) gives a significantly greater reduction in plant height, a greater increase in spikelet and ear fertilities, slightly less reduction in 1000‐grain weight, and significantly higher spikelet, ear and plot yields. If these results are repeatable in other varietal backgrounds, over seasons, and under differing environmental conditions,Rht1 (B. dw) should have considerable commercial potential as an alternative allele for producing shorter‐than‐average, high‐yielding, semi‐

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1995.tb00819.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractThe genetic distances between two cultivated wheat (Triticum aestivumL.) varieties (Martonvásári 9, Martonvásári 15), a Martonvásári 9 line possessing the crossability genekrl, and 21 accessions ofT. timopheeviZhuk. andT. araraticumJakubz. were estimated, based on agro‐morphological, physiological and biochemical analysis of data. Cluster analysis based on Mahalanobis' D2values was applied. All 21 accessions ofT. timopheeviandT. araraticumcould be classified into eight clusters. Clusters I and II consisted of all theT. timopheevi, whileT. araraticumwas located in six clusters. Discriminant analysis was applied to test significant differences between cluster pairs. The genetic distance (GD) based on the electrophoretic data of gliadins indicated two types of electrophoregrams inT. timopheevvi, distinguished as groups A and B.T. araraticumaccessions were variable as regards the spectra. Mean, minimum and maximum GD were estimated within and between different wheat groups based on acid polyacrylamide gel electrop

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1995.tb00820.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractA collection of 180Triticum durumlines from Turkey and 22 Italian cultivars were investigated by electrophoretic techniques and evaluated for grain parameters such as protein content and sodium dodecyl sulphate (SDS)‐sedimentation test. A total of 14 different patterns were observed for high‐molecular‐weight (HMW) glutenin subunits resulting from the combination of three alleles from the A genome and seven from the B genome. Three new allelic variants, one atGlu‐A1and two atGlu‐B1, were found. Five different alleles were detected at theGlu‐B1locus. Genotypes with the same allelic variant atGli‐B1showed inconsistency of composition in B group of low‐molecular‐weight (LMW) glutenin subunits. A total of 11 different B‐subunit patterns were identified in the material analysed. A substantial proportion (78%) of the variation in gluten properties could be explained in terms of protein composition, with the LMW glutenin subunits making the largest contribution (54%). Results indicate that, in addition toGlu‐B3encoded proteins, variation at other loci coding for some intermediate and fastest B subunits might also influence r

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1995.tb00821.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractA collection of 299 secondary hexaploid triticale cultivars and advanced breeding lines from 18 countries, which were considered a representative sample of the existing diversity, was evaluated for morphological and agronomical characters with autumn planting at Lleida, Spain, from 1988 to 1991. The entries were classified as having winter (84) or spring (215) growth habit and among this latter group were complete (73) or substituted (147) types according to CIMMYT's terminology. Winter and spring triticales were grouped by cluster and principal component analyses. Winter triticales were taller with longer growth cycles, longer spikes, and more spikelets per spike than spring types. At early stages they also had prostrate growth. Spring‐substituted types were separated from complete material. As a group, spring‐substituted triticales differed more from winter types than the spring complete genotypes, which showed intermediate characteristics. Complete types of spring habit had tendency to be taller, with longer spikes, more spikelets per spike and bigger and heavier grains than substituted triticales. Greater variation in morphological and agronomical parameters was detected among winter triticales followed by the complete‐spring

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1995.tb00822.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractA breeding programme was developed to obtain barley yellow dwarf virus (BYDV)‐resistant winter genotypes using theYd2gene. The aim was to incorporate theYd2allele into the new high‐yielding genotypes to release cultivars that allow barley cultivation in areas where BYDV is endemic.The resistant lines were developed using pedigree selection. An ICARDA resistant line (83RCBB130) carrying theYd2gene was crossed with three susceptible, high‐yielding winter varieties and their F1lines were either selfed or backcrossed to the matching susceptible parent. The best lines selected from subsequent selfing generations were evaluated in replicated trials in the presence or absence of BYDV, starting from F6and BC1F5to F8and BC1F7generations. Four genotypes with superior agronomic traits and BYDV resistance were sel

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1995.tb00823.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractResistance to potato viruses was examined in the F1hybrids (TET) obtained from a cross between a diploid (2n = 24), tuber‐bearing interspecific hybrid 87HW13.7 (Solanum tuberosumW231 ×S. multi‐dissectumPI 473354) and a diploid (2n = 24), nontuber‐bearing wild potato species (S. brevidensCPC 2451) usingS. phurejaIvP35 (2n = 24) for rescue pollination. The parental plants were susceptible to PVX, whereas two hybrids (TET38.2 and TET38.9) andS. phurejaIvP35 reacted with hypersensitivity to PVX. Two hybrids (TET 38.9 and TET 38.12) were extremely resistant to PVY°, which was similar toS. brevidensandS. phurejaIvP35, whereas the remaining two hybrids were moderately resistant to PVY°. No resistance to PVA and PLRV was observed in the progenies, in contrast toS. brevidenswhich was extremely resistant to PVA and PLRV. Hypersensitivity to PVX in two progenies suggested (1) integration by somatic translocation or heterofertilization and expression of genes from the rescue pollinatorS. phurejaIvP35, or (2) transgressive or complementary gen

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1995.tb00824.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractAs it is related to the variability in genome expression, variability in protein quantities revealed by two‐dimensional electrophoresis was proposed for describing phenotypic diversity. The objective of this study was to compare the predictive power of different genetic distances derived from molecular markers and from protein quantitative variations in a diallel of 210 hybrids among 21 maize inbred lines (Zea maysL.) of various origin. The lines were characterized for: 1. 142 markers resulting from the analysis of enzyme, RFLP, and protein‐structure polymorphism; and 2. The variation in relative quantities of 190 proteins. The hybrids were evaluated for six forage traits in four environments. Correlations between the genetic distances computed for 142 marker loci and hybrid performances were moderate to high in diallels using crosses between related lines. Genetic distances based on protein quantities showed, in most cases, similar or lower correlations. Distance measures were not useful as predictors of hybrid performance for crosses between unrelated lines. Protein quantities were better for revealing specific genoty

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1995.tb00825.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY