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1.
Inheritance of resistance to Karnal bunt was investigated in the crosses of four resistant synthetic hexaploid wheats (SH; Triticum turgidum×T. tauschii) and two susceptible T. aestivum cultivars. The resistance was dominant or partly dominant over susceptibility. The SH cultivars Chen/T. tauschii (205) and Chen/T. tauschii (224) have single dominant resistance genes which could be allelic to each other. ‘Altar 84’/T. tauschii (219) appeared to have two dominant genes for resistance. ‘Duergand’T. tauschii (214) possessed two complementary dominant genes for resistance. The work is being extended to involve diverse Karnal bunt-resistant SH and bread wheat cultivars. 相似文献
2.
Triticum tauschii provides breeders with a valuable source of resistance and tolerance genes. Elucidation of the inheritance of traits in this species that hinder its use in breeding programmes is therefore of interest to wheat breeders. Inheritance of threshability was investigated in the crosses of four non-free-threshing (NFT) synthetic hexaploids (Triticum turgidum×T. tauschii) and two free-threshing (FT) T. aestivum cultivars during four crop seasons over 3 years at E1 Batan and Ciudad Obregon, Mexico. The parents, their F1 Hybrids and individual F2 plant-derived F3 progenies of the crosses revealed that ‘Altar 84’/T. tauschii (219), ‘Chen’/T. tauschii (205), ‘Chen’/T. tauschii (224), and ‘Duergand’/T. tauschii (214) have independently segregating loci with two dominant alleles controlling threshability. Intercrosses among the synthetics, except ‘Altar 84’/T. tauschii (219), showed the genes to be allelic to each other. The cross between the FT cultivars showed no segregation in the F3 generation, indicating common recessive genes. Based on these findings, population sizes of the synthetic-derived breeding materials should be increased to improve the chances of selecting FT desirable plants in the programme. 相似文献
3.
The bottleneck restricting introgression of useful genes directly from diploid into hexaploid wheats is the low number of BC1F1 seeds obtained. In crosses between hexaploid wheat (Triticum aestivum L.; AABBDD) and Aegilops squarrosa L. (DD) or T. urartu Thum. (AA), this bottleneck may be overcome simply by pollinating a sufficient number of F1 spikes. However, hybrids between hexaploid wheat cultivars (T. aestivum) and T. monococcum L. (AA) generally are highly female-sterile, often having no pistils. One T. monococcum accession, PI 355520, when crossed with T. aestivum, produced hybrids with female fertility in the same range as that of T. aestivum/A. squarrosa or T. aestivum/T. urartu hybrids, ca. 0.5 to 1.0 backcross seed per spike. We found that female fertility was controlled by two duplicate genes in PI 355520, and that this accession can be used as a bridging parent to introgress genes from other T. monococcum accessions into hexaploid wheat. Pairing of homologous chromosomes was less frequent and weaker in such crosses than in T. aestivum/A. squarrosa crosses, but homoeologous bivalents occurred at a rate of almost 0.5 II per cell. Restitution division was detected in crosses involving all three diploid species and was confirmed cytologically in crosses with PI 355520. Chromosome numbers of BC1F1 plants ranged from 35 to 67; plants with 49 or more chromosomes occurred at frequencies of 0.09 to 0.21 among progeny of A. squarrosa and T. urartu and 0.29 in progeny of T. aestivum/T. monococcum crosses involving PI 355520. These results are consistent with those of previous studies, demonstrating the potential of direct Hexaploid/diploid crosses for rapidly introgressing useful genes into Hexaploid wheat with minimum disturbance of the background genotype. 相似文献
4.
Triticum tauschii (Coss.) Schmal. is an ancestor of bread wheat (T. aestivum). This species has been widely used as a source ofsimply-inherited traits, but there are few reports of yield increases due tointrogression of genes from this species. Selections from F2-derivedlines of backcross derivatives of synthetic hexaploid wheats (T.turgidum / T. tauschii) were evaluated for grain yield in diverseenvironments in southern Australia. Re-selections were made in theF6 generation and evaluated for grain yield, yield componentsincluding grain weight, and grain growth characters in diverse environmentsin southern Australia and north-western Mexico. Re-selection was effectivein identifying lines which were higher yielding than the recurrent parent,except in full-irrigation environments. Grain yields of the selectedderivatives were highest relative to the recurrent parent in thelowest-yielding environments, which experienced terminal moisture deficitand heat stress during grain filling. The yield advantage of the derivativesin these environments was not due to a change in anthesis date orgrain-filling duration, but was manifest as increased rates of grain-filling andlarger grains, indicating that T. tauschii has outstanding potential forimproving wheat for low-yielding, drought-stressed environments. 相似文献
5.
Twelve primary hexaploid triticale (X Triticosecale Wittmack), synthesized from, three lines of tetraploid wheat (Triticum durum L., T. turgidum L.) and four inbred lines of rye (Secale cereale L.), were used to produce 18 crosses with homozygous wheat and heterozygous rye genome and 12 crosses with heterozygous wheat and homozygous rye genome. Parents and crosses of triticale, wheat, and rye were tested for two years (rye for one year only) in two-replicate block designs with 1 m2-plots. Data were assessed for plant height, grain yield and for yield-related traits. Performance of triticale crosses was considerably lower than that of the wheat and rye crosses. The amount of heterosis varied greatly between years. Positive and mainly significant heterosis was revealed in triticale generations F1 and F2. The average values were closer to those in wheat than to those in rye. For most characters a high level of heterosis was retained in tnucalt1 generation F2. Heterozygosity of the wheat and rye genome both contributed to heterosis in triticale. However, gene action of the rye genome strongly depended on the homozygous wheat background: one wheat line almost completely suppressed and another greatly stimulated the heterotic effect of the rye genome. In the later case, the amount of heterosis was related to that in rye per se. Information from hybrid rye breeding may therefore be used when establishing gene pools for hybrid breeding in triticale. 相似文献
6.
Summary Wheat pentaploids were produced by hybridizing a high kernel weight (1000 grain wt=56 g), high protein (25.4%) line of wild tetraploid wheat (Triticum turgidum dicoccoides) as male parent, with the three hexaploids (T. aestivum) — normal Chinese Spring and its two homoeologous pairing mutants, ph
1b and ph
2. The pentaploids were crossed as female parents to the two commercial hexaploid cultivars Warigal and Barkaee and 42-chromosome stable plants selected from the F1 of the pentaploid x hexaploid crosses.Mean protein content of certain F3 lines from all six pentaploid x hexaploid crosses was significantly higher than Chinese Spring and the respective commercial hexaploid parent (p<0.005) indicating high protein had been transferred from the tetraploid to the hexaploid level.Kernel weight amongst certain F3 lines of the three pentaploids x Barkaee was significantly (p<0.0005) higher than either Chinese Spring or Barkaee, indicating the transfer also of high kernel weight from the tetraploid to the hexaploid level. However kernel weight was not significantly increased over Warigal in any F3 lines of its crosses with the three pentaploids.High levels of homoeologous chromosome pairing in the ph-mutant pentaploids, plus evidence for significant modification of the composition of high-molecular weight (HMW) glutenin subunits of grain protein in certain F3 derivatives of the ph-mutant pentaploid x hexaploid, crosses indicates that the ph-mutant-derived lines may possess novel (intergenome) genetic recombination, at least for high protein, and possibly kernel weight. 相似文献
7.
Synthetic hexaploid wheats are of interest to wheat breeding programs, especially for introducing new genes that confer resistance
to biotic and abiotic stresses. A group of 54 synthetic hexaploid wheats derived from crosses between emmer wheat(Triticum dicoccum, source of the A and B genomes) and goat grass (Aegilops tauschii, D genome donor) were investigated for genetic diversity. Using the AFLP technique, dendrograms revealed clear grouping according
to geographical origin for the T. dicoccum parents but no clear groups for the Ae. tauschii parents. The geographical clustering of the T. dicoccum parents was also reflected in the dendrogram of their derived synthetic hexaploids. Diversity of the T. dicoccum parents and their derived synthetic hexaploids was further evaluated by measuring 18morphological and agronomic traits on
the plants. Clustering based on morphological and agronomic data also reflected geographical origin. However, comparison of
genetic distances obtained from AFLP and agronomic data showed no correlation between the two diversity measurements. Nevertheless,
similarities among major clusters with the two systems could be identified. Based on percentage of polymorphic markers, the
synthetic hexaploids had a considerably higher level of AFLP diversity (39%) than normally observed in cultivated hexaploid
wheat (12–21%). This suggests that synthetic hexaploid wheats can be used to introduce new genetic diversity into the bread
wheat gene pool.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
8.
Wheat pre-breeding using wild progenitors 总被引：6，自引：1，他引：6
J. J. Valkoun 《Euphytica》2001,119(1-2):17-23
To facilitate the use of wheat wild relatives in conventional breedingprograms, a wheat pre-breeding activity started at ICARDA in 1994/1995season. Preliminary results of gene introgression from wild diploidprogenitors, Triticum urartu, T. baeoticum, Aegilops speltoides andAe. tauschii and tetraploid T. dicoccoides are described. Crosseswith wild diploid Triticum spp. yielded high variation in plant andspike morphology. Synthetic hexaploids were produced from crosses of alocal durum wheat landrace `Haurani' with two Ae. tauschiiaccessions. Both Ae. tauschii accessions carry hybrid necrosis allelesthat gave necrotic plant phenotypes in crosses with some bread wheats.Backcross progenies with agronomical desirable traits, i.e. high spikeproductivity, short plant stature, earliness, drought tolerance and highproductive tillering, were identified in crosses of durum wheat with wild Triticum spp. and in a cross of one of the hexaploid synthetics with alocally adapted bread wheat cv. `Cham 6'. Resistance to yellow rust wasfound in durum wheat crosses with the three wild Triticum spp. andAe. speltoides and leaf rust resistance was identified in crosses withT. baeoticum and Ae. speltoides. The results show that wheatimmediate progenitors may be a valuable and readily accessible source ofnew genetic diversity for wheat improvement. 相似文献
9.
Fourteen Mexican genotypes of bread wheat (Triticum aestivum L.) with good to moderate levels of resistance to Karnal bunt (Tilletia indica (Mitra)) were crossed with the highly susceptible cultivar WL711 to determine the genetic basis of resistance. The parents, F1 F2 and backcross populations of the 14 crosses were evaluated under artificial epiphytotic conditions during the 1993–94 season for Karnal bunt resistance. The F1 data suggested that the resistance was dominant to partially dominant over susceptibility. The F2 analysis of the segregation ratios in the F2 and backcross generations indicated that the resistance in the wheat genotypes Luan, Attila, Vee #7/Bow, Star, Weaver, Milan, Sasia and Turacio/Chil is controlled by two genes. The resistance in genotypes Cettia, Irena, Turaco, Opata, Picus, and Yaco was found to be conditioned by a single dominant gene. The genotypes with two genes for resistance expressed a higher level of resistance than those with a single gene and, therefore, are better sources of resistance to Karnal bunt. 相似文献
10.
The introduction into bread wheat of a major gene for resistance to powdery mildew from wild emmer wheat 总被引：19，自引：0，他引：19
Summary A new source of resistance to wheat powdery mildew caused by Erysiphe graminis has been transferred to hexaploid bread wheat, Triticum aestivum, from the wild tetraploid wheat, Triticum dicoccoides. The donor was crossed to bread wheat and the pentaploid progeny was then self-pollinated. Plants having a near stable hexaploid chromosome complement were selected in the F3 progeny and topcrossing and backcrossing of these to a second wheat cultivar to improve the phenotype was undertaken. Monosomic analysis of early backcross lines showed the transferred gene to be located on chromosome 4A. The gene has been designated Pm16. 相似文献
11.
Lin Huang Lian-Quan Zhang Bao-Long Liu Ze-Hong Yan Bo Zhang Huai-Gang Zhang You-Liang Zheng Deng-Cai Liu 《Euphytica》2011,179(2):313-318
Stripe rust, caused by Puccinia striiformis f. sp. tritici (PST), is one of the most important diseases of common wheat (Triticum aestivum L.). China has the largest stripe rust epidemic areas in the world and yield losses can be large. Aegilops tauschii Coss, the D-genome progenitor of common wheat, includes two subspecies, tauschii and strangulata (Eig) Tzvel. The ssp. strangulata accession AS2388 is highly resistant to the prevailing physiological races of PST in China, and possesses a single dominant
gene for stripe rust resistance. In order to tag this gene, AS2388 was crossed with the highly susceptible ssp. tauschii accession AS87. The parents, F2 plants, and F2:3 families were tested at adult plant stage in field trials with six currently prevailing races. Simple sequence repeat (SSR)
primers were used to identify molecular markers linked to the resistance gene. SSR markers Xwmc285 and Xwmc617 were linked to the resistance gene on chromosome arm 4DS flanking it at 1.7 and 34.6 cM, respectively. Based on the chromosomal
location, this gene temporarily designated as YrAS2388 is probably novel. The resistance in Ae. tauschii AS2388 was partially expressed in two newly developed synthetic hexaploid backgrounds. 相似文献
12.
Glaucous leaf and tough rachis phenotypes are rare in Aegilops tauschii, the D genome donor to common wheat (Triticum aestivum). The genes for glaucous leaf and tough rachis were mapped using microsatellite probes in A. tauschii. The glaucous phenotype was suppressed by the inhibitor W2I located on chromosome 2DS. The gene W2I was mapped to the distal part of 2DS, and was unlinked to the centromere. This suggests that the distance of the W2I locus from the centromere was maintained during the evolution of hexaploid wheat from its diploid progenitors as the inhibitor
gene is at the same position in A. tauschii and bread wheat. The Brt (Brittle rachis of A. tauschii) locus was located on the short arm of chromosome 3D, and was 19.7 cM from the centromeric marker, Xgdm72.3D. Brt causes breakage of the spike at the nodes, thus creating barrel-shaped spikelets, while Br1 in hexaploid wheat causes breakage above the junction of the rachilla with the rachis such that a fragment of rachis is attached
below each spikelet. 相似文献
13.
It was recently shown that allopolyploidy brings novel epistatic interactions to genes belonging to different genomes. However, systematic studies of the phenotypic relationships between synthetic hexaploid wheats and their parental lines have not been conducted. In this study, 27 synthetic hexaploid wheats were produced by crossing the tetraploid wheat cultivar ‘Langdon’ with 27 accessions of Aegilops tauschii. Variations in 20 morphological and flowering traits were analysed in both the synthetic wheat lines and the parental Ae. tauschii accessions. The 20 traits exhibited large variations in the wheat lines. For many of the traits, the degree of variation in the parental accessions was reduced in the hexaploid derivatives. Principal component analysis of floret‐related traits divided the Ae. tauschii accessions into two subspecies, ssp. tauschii and ssp. strangulata, but this parental pattern of subspecific division was not detectable in the hexaploids. Our results suggest that the ‘Langdon’ genome may have an alleviating effect on the expression of D‐genome‐derived variations in derived synthetics. 相似文献
14.
The gene pool of Aegilops tauschii, the D-genome donor of common wheat (Triticum aestivum L.), can be easily accessed in wheat breeding, but remains largely unexplored. In our previous studies, many synthetic hexaploid wheat lines were produced through interspecific crosses between the tetraploid wheat cultivar Langdon and various A. tauschii accessions. The synthetic hexaploid wheat lines showed wide variation in many characteristics. To elucidate the genetic basis of variation in flowering-related traits, we analyzed quantitative trait loci (QTL) affecting time to heading, flowering and maturity, and the grain-filling period using four different F2 populations of synthetic hexaploid wheat lines. In total, 10 QTLs located on six D-genome chromosomes (all except 4D) were detected for the analyzed traits. The QTL on 1DL controlling heading time appeared to correspond to a flowering time QTL, previously considered to be an ortholog of Eps-A m 1 which is related to the narrow-sense earliness in einkorn wheat. The 5D QTL for heading time might be a novel locus associated with wheat flowering, while the 2DS QTL appears to be an allelic variant of the photoperiod response locus Ppd-D1. Some of the identified QTLs seemed to be novel loci regulating wheat flowering and maturation, including a QTL controlling the grain filling period on chromosome 3D. The exercise demonstrates that synthetic wheat lines can be useful for the identification of new, agriculturally important loci that can be transferred to, and used for the modification of flowering and grain maturation in hexaploid wheat. 相似文献
15.
Summary Variation in pigment content of the flour of bread wheats (Triticum aestivum L.) was studied in the progenies of F1 and F2 of three crosses and their reciprocals. Reciprocal differences in pigment content were observed in the F1 and F2 means. Low pigment content was found to be partially dominant or over dominant in the crosses studied. There was evidence of substantial mid-parent F1 heterosis in all crosses and betterparent F1 heterosis in three crosses. In the F2, heritability estimates were moderate to high. The F2 frequency distributions were not normal. Estimation of effective factor pairs indicated the presence of one or two major gene pairs involved in the expression of pigment content in the flour. Action of modifiers was also assumed in one cross and its reciprocal. A factorial approach to metrical character suggested that the F2 segregation ratios of low pigment content to high pigment content were 3:1, 15:1, 13:3 and 9:7 for the different crosses. Utilization of the findings in a wheat breeding program is briefly discussed. 相似文献
16.
Yuki Okamoto Anh T. Nguyen Motohiro Yoshioka Julio C.M. Iehisa Shigeo Takumi 《Breeding Science》2013,63(4):423-429
Synthetic hexaploid wheat is an effective genetic resource for transferring agronomically important genes from Aegilops tauschii to common wheat. Wide variation in grain size and shape, one of the main targets for wheat breeding, has been observed among Ae. tauschii accessions. To identify the quantitative trait loci (QTLs) responsible for grain size and shape variation in the wheat D genome under a hexaploid genetic background, six parameters related to grain size and shape were measured using SmartGrain digital image software and QTL analysis was conducted using four F2 mapping populations of wheat synthetic hexaploids. In total, 18 QTLs for the six parameters were found on five of the seven D-genome chromosomes. The identified QTLs significantly contributed to the variation in grain size and shape among the synthetic wheat lines, implying that the D-genome QTLs might be at least partly functional in hexaploid wheat. Thus, synthetic wheat lines with diverse D genomes from Ae. tauschii are useful resources for the identification of agronomically important loci that function in hexaploid wheat. 相似文献
17.
Parental effects on crossability,embryo differentiation and plantlet recovery in wheat x rye hybrids
Gitta Oettler 《Euphytica》1984,33(1):233-239
Summary One hexaploid wheat cultivar (Triticum aestivem) and two tetraploid wheat lines (T. durum) were crossed with seventeen inbred lines of rye (Secale cereale). Seed set, degree of hybrid embryo differentiation at the time of excision for in vitro culture and recovery of amphihaploid plantlets from various embryo categories were studied. Degree of embryo differentiation was predominantly determined by maternal wheats, paternal rye genotypes appearing to be of minor importance. T. aestivum x rye hybrid embryos were superior to those produced from T. durum for degree of differentiation. The proportion of plantlets developing from differentiated embryos was high for all wheat parents, whereas undifferentiated embryos were mostly unsuitable for plantlet production. The results revealed that cross-incompatibility in hexaploid wheat x rye crosses was due to failure of fertilization, while in tetraploid wheat x rye crosses it was caused by lack of embryo differentiation. Correlation analyses showed that seed set provided a criterion to predict the amphihaploid plantlets to be expected from a particular wheat x rye combination. 相似文献
18.
Variation of harvest index in several wheat crosses 总被引：2，自引：0，他引：2
G. M. Bhatt 《Euphytica》1976,25(1):41-50
Summary Harvest index was studied in F1 and F2 generations of eight wheat (Triticum aestivum L.) crosses and their reciprocals. The parental varieties involved in the crosses represented a fairly wide range of character expression for plant height, tillering potential, grain yield per plant and harvest index. Differences between reciprocal crosses were not evident for the expression of harvest index of the crosses under study. Means and degrees of dominance of F1 and F2 populations suggested partial dominance of high harvest index over low harvest index. The pattern of variation among F2 segregates was quantitative and the distribution was normal. The gene action governing the expression of harvest index was largely additive. Evidence was obtained for non-additive gene action in some crosses. There was complete absence of high parent heterosis for harvest index in the F1's but midparent heterosis was found to be present in all crosses. Estimates of heritability and genetic advance were moderate to high. Usefulness of selecting for harvest index as a measure of yield efficiency particularly in early generations is discussed. 相似文献
19.
Summary A simple method is proposed to distinguish hexaploid (Triticum aestivum L.) from tetraploid (Triticum turgidum L., durum wheat) cultivated wheats on the basis of peroxidase isozymes coded by genome D. It can also be used as a first step to detect possible contamination by tetraploid genotype mixtures. The peroxidase patterns of endosperm and of embryo plus scutellum found among 349 entries of a durum wheat world basis collection are shown. 相似文献
20.
The inheritance of resistance to root‐lesion nematode was investigated in five synthetic hexaploid wheat lines and two bread wheat lines using a half‐diallel design of F1 and F2 crosses. The combining ability of resistance genes in the synthetic hexaploid wheat lines was compared with the performance of the bread wheat line ‘GS50a’, the source of resistance to Pratylenchus thornei used in Australian wheat breeding programmes. Replicated glasshouse trials identified P. thornei resistance as polygenic and additive in gene action. General combining ability (GCA) of the parents was more important than specific combining ability (SCA) effects in the inheritance of P. thornei resistance in both F1 and F2 populations. The synthetic hexaploid wheat line ‘CPI133872’ was identified as the best general combiner, however, all five synthetic hexaploid wheat lines possessed better GCA than ‘GS50a’ The synthetic hexaploid wheat lines contain novel sources of P. thornei resistance that will provide alternative and more effective sources of resistance to be utilized in wheat breeding programmes. 相似文献