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1.
Five parents of common vetch (Vicia sativa L.) having orange/beige cotyledon colour, brown/white testa colour, purple/green seedling colour and purple/white flower colour were crossed as a full diallele set. The inheritance patterns of cotyledon, testa or seed coat colour, flower and seedling colour, were studied by analyzing their F1, F2, BC1 and BC2 generations. The segregation pattern in F2, BC1 and BC2, showed that cotyledon colour was governed by a single gene with incomplete dominance and it is proposed that cotyledon colour is controlled by two allelic genes, which have been designated Ct1 and Ct2. Testa colour was governed by a single gene with the brown allele dominant and the recessive allele white. This gene has been given the symbol H. Two complementary genes governed both flower and seedling colours. These flower and seedling colour genes are pleiotropic and the two genes have been given the symbols S and F.  相似文献   

2.
Summary Since June 1973 Pseudoperonospora cubensis (Berk & Curt) Rost., which causes downy mildew in cucumber, occurs in the Netherlands. The resistance against this disease appears to be based on one recessive gene in linkage with the dominant gene D for dull green fruit skin colour. It is demonstrated that this recessive gene is also linked with one of the genes for resistance to powdery mildew present in the variety Ashley.The powdery mildew resistant lines tested are also resistant against downy mildew, the linkage with the gene D having been broken.Stationed at Breeding Station Pannevis B.V., De Lier, the Netherlands.  相似文献   

3.
Summary The oat line Pc54 was found to be resistant to powdery mildew under both field and glasshouse conditions. The ratio of resistant to susceptible F2 and F2 progeny of a cross between a selection from the Pc54 line (Cc7422) and a susceptible cultivar (Selma) showed that, in addition to carrying the crown rust resistance gene Pc54 and the pg15 gene for stem rust resistance, the mildew resistance of the Pc54 line was conditioned by a single incompletely dominant gene along with additional factors which modified the expression of resistance. Previous results, that there was no linkage between genes Pc54 and Pg15, were confirmed. In addition, there was no evidence of linkage between the mildew resistance gene and gene Pc54. Evaluation of selections from within the Pc54 line showed that the expression of both stem rust and mildew resistance was modified by, or linked to, plant height. The effectiveness of genes Pc54 and Pg15, as measured by virulence frequencies, in central and eastern Europe is described.  相似文献   

4.
In the framework of variety testing, evaluation of the flower of Begonia x tuberhybrida Voss. is done by experts. The colours of the flowers are compared with the RHS colour chart. For each flower colour a code is given. This method has several disadvantages (data cannot be statistically analyzed with standard ANOVA techniques, bias by the expert is possible, difficult measurement depending on the light environment, ...) that can be overcome with image analysis. In this study several parameters were tested to distinguish the different varieties. Varieties were split in different colour groups (white, red and yellow–orange) and parameters were analyzed. Parameters based on the green colour plain of the RGB colour space resulted in the largest discriminating power. Parameters based on the HSV colour space performed less well.  相似文献   

5.
The mildew reactions of the second generation of doubled haploid (DH) plants, derived from anther culture of crosses among three spring barley lines carrying different Mla mildew resistance alleles and the cv. ‘Pallas’, were analyzed by using a set of three European and one Israeli mildew isolate. The results indicated, (1) a significant level of distortion segregation in favour of resistant DH genotypes, which was possibly due to linkage of mildew resistance genes on chromosome 5 with genes for plant regeneration and (2) various degrees of dominance for the different resistance genes studied as well as the possible action of modifier genes.  相似文献   

6.
Wheat powdery mildew and stripe rust, caused by Blumeria graminis f.sp.tritici (syn. Erysiphe graminis f.sp.tritici) and Puccinia striiformis Westend., respectively, are two important fungal diseases of wheat in many regions in the world that cause significant annual yield losses. In the present study, a dominant powdery mildew and a dominant stripe rust resistance gene in wheat line 101-3 which derived from the progenies of the wide cross between common wheat and Dasypyrum villosum Candary L., was located on chromosome 6B and 1B, respectively, by monosomic analyses. The two genes are different from known resistance genes on chromosome 6B for powdery mildew and 1B for stripe rusts, suggesting that the two genes might be novel resistance genes for powdery mildew and stripe rust, respectively. It is uncertain whether the two genes are allelic or lined with other resistance genes located on chromosome 6B for powdery mildew and 1B for stripe rust. Further allelism tests are necessary to determine the relationships between the resistance gene and other genes located on chromosome 6B for powdery mildew and 1B for stripe rust through molecular markers.  相似文献   

7.
Genetical studies on mildew resistance were carried out with Hordem spontaneum derived lines. A total of 28 lines (66 %) showed monofactorial segregation for mildew resistance, For 14 lines, a bifactorial mode of inheritance was found. In total fifty six mildew resistance genes take part in the inheritance of mildew resistance of the H. spontaneum derived lines, while the presence of known genes for mildew resistance (i.e, Ml-a.9 and Ml-p) was established only in two cases. Independent segregation from the Ml-a locus was found in 10 mbnofaetorial segregating lines, The genes conditioning mildew resistance in barley lines derived from the accessions 1B-54B, RS 170-47, RS 20-1. 1B-86B, RS 145-39 and 1B–152B of H. spontaneum were closely linked or alleles to the Ml-a locus, but shown to be different from 15 previously identified Ml-a alleles. It is suggested that these genes should be designated Ml-a16, Ml-18, Ml-19 Ml-20 and Ml-a21 respectively. No recombinants were found in test crosses when both parents carried genes/alleles of the Ml-a locus. In addition, polymorphism has been observed also for the Ml-a locus. In 4 lines mildew resistance was conditioned by two dominant complementary genes. For one of the 2 genes, conditioning mildew resistance of line RS 42-8 × OrioL a new locus was found located near the centromere of the long arm of chromosome 5, and should be designated Ml-i The potential use of H. spontaneum genes for mildew resistance in barley breeding is discussed.  相似文献   

8.
Inheritance of a novel corolla colour in periwinkle [Catharanthus roseus (L) G. Don], viz. magenta, was studied by crossing an accession MJ, possessing this corolla colour, with cultivar Nirmal, possessing white corolla. The accession MJ was also crossed with another accession OR, possessing another novel corolla colour, viz. orange-red, to determine the relationship between genes governing magenta corolla and orange-red corolla. The F1 plants of the cross MJ× Nirmal had pink corolla and red eye. In the F2 generation, five kinds of corolla colours were observed: (i) pink corolla and red eye, (ii) rose corolla and red eye, (iii) magenta corolla and red eye, (iv) white corolla and red eye and (v) white corolla. The observed frequencies of the five kinds of plants fitted a ratio of 144:27:9:12:64. The progeny of the backcross, F1 × MJ, segregated into three kinds of plants, (i) pink corolla and red eye, (ii) rose corolla and red eye and (iii) magenta corolla and red eye, in the ratio of 2:1:1, while the backcross, F1 × Nirmal, segregated into two kinds of plants, (i) pink corolla and red eye and (ii) white corolla, in the ratio of 1:1. Two new genes (proposed symbols Om and J) appeared to be involved in the determination of magenta and rose corolla colours. Interaction between four independent genes R, W, Om and J, appeared to explain the observed segregation in the cross MJ × Nirmal. The F1 plants of the cross MJ × OR had scarlet-red corolla and red eye. The segregation data of F2 and backcross generations suggested that genes governing orange-red corolla and magenta corolla were allelic to each other. Two new and non-parental corolla colours viz., rose corolla and scarlet-red corolla, were observed in the progeny of the crosses of the present study.  相似文献   

9.
Powdery mildew resistance in cucumber   总被引：7，自引：0，他引：7  
E. Kooistra 《Euphytica》1968,17(2):236-244
Summary Powdery mildew in cucumbers (Cucumis sativus L.) can be caused by two fungi, Erysiphe cichoracearum and Sphaerotheca fuliginea. In The Netherlands we have been mainly concerned with the latter, at least during the last few years.A high degree of resistance to S. fuliginea was obtained by combinations of progenitors that are in themselves insufficiently resistant. It was made plausible that the resistance obtained is governed by three recessive genes.The relation to the resistance against E. cichoracearum, mentioned elsewhere, is discussed.  相似文献   

10.
Summary Genes Yr1 for resistance to stripe rust and Pm4a for resistance to powdery mildew showed linkage of 2.0±0.6 cM. Close repulsion linkage probably accounts for the absence in European wheats of genes Yr1 and Pm4b in combination.  相似文献   

11.
Summary Four newly detected accessions of wild barley (Hordeum vulgare ssp. spontaneum) resistant to powdery mildew caused by Blumeria graminis f. sp. hordei were studied with the aim of finding the number of genes/loci conferring the resistance of individual accessions, the type of inheritance of the genes and their relationships to the Mla locus. F2 populations after crosses between the winter variety ‘Tiffany’ and four wild barley accessions and use of microsatellite DNA markers were focused on the identification of individual resistance genes/loci by means of their chromosomal locations. In PI466495, one locus conferring powdery mildew resistance was identified in highly significant linkage with the marker Bmac0213. This location is consistent with the known locus Mla on chromosome 1HS. In the other three accessions the resistance was determined by two independent loci. In PI466197, PI466297 and PI466461, one locus was identified on chromosome 1HS and three new loci were revealed on chromosomes 2HS (highly significant linkage with Bmac0134), 7HS (highly significant linkage with Bmag0021) and 7HL (significant linkage with EBmac0755). Our prospective aim is identification of further linked DNA markers and the exact location of the resistance genes on the barley chromosomes.  相似文献   

12.
Summary Colour is the major contributor to the total ornamental value of a flower. The combination of biochemical knowledge and genetic engineering technology has resulted in the addition of a new colour to the existing colour range of Petunia hybrida. This has been achieved by expression of the maize dihydroflavonol-4-reductase (dfr) gene in a suitable petunia acceptor which leads to the accumulation of pelargonidin-derived pigments in flowers. The resulting flower colour, however, was a pale brick-red, which is commercially unattractive in petunia.Our objective was to produce a product suitable for commercialisation by introducing the dfr gene into our breeding material via normal sexual recombination. Although the initial transformant exhibited many negative characteristics, first analyses indicated that it was feasible to obtain suitable material for creating commercial hybrids. Experimental hybrids based on F4 lines were obtained with improved phenotypic expression of the orange flower colour in combination with a good general performance.In order to assess consumer-related characteristics, selected experimental hybrids were tested under field conditions. All transgenic plants had a normal appearance when compared with non-transgenic control plants. No linkage was observed between the transgenic trait and any negative characteristic. From these studies it can be concluded that through a combination of biochemistry, breeding and genetic engineering, it is possible to generate unique flower colours in a cultivars with commercial potential.  相似文献   

13.
Summary Inheritance and linkage relationships were studied for six morphological characters in a cross between Arachis monticola Krap. et Rig. and A. hypogaea L. All the characters were found to be governed by single dominant genes. The genes governing leaflet krinkling and peg pigmentation assorted independently while the genes for four pod characters viz. catenate nature, beak, reticulation and thin pericarp showed linkage. A linkage map for these genes was proposed.  相似文献   

14.
Molecular mapping of powdery mildew resistance genes in wheat: A review   总被引：40，自引：3，他引：40  
Powdery mildew, caused by Blumeria graminis f. sp. tritici (syn. Erysiphe graminis f. sp. tritici), is one of the most important diseases of common wheat (Triticum aestivum L.) worldwide. Molecular mapping and cloning of genes for resistance to powdery mildew in hexaploid wheat will facilitate the study of molecular mechanisms underlying resistance to powdery mildew diseases and help understand the structure and function of powdery mildew resistance genes, and permit marker-assisted selection in breeding programs. So far, 48 genes/alleles for resistance to powdery mildew at 32 loci have been identified and located on 16 different chromosomes, of which 21 resistance genes/alleles have been tagged by restriction fragment length polymorphisms (RFLPs), random-amplified polymorphic DNAs (RAPDs), amplified fragment length polymorphisms (AFLPs), sequence characterized amplified regions (SCARs), sequence-tagged sites (STS) or simple sequence repeats (SSRs). Several quantitative trait loci (QTLs) for adult plant resistance (APR) to powdery mildew have been associated with molecular markers. The detailed information on chromosomal location and molecular mapping of these genes has been reviewed. Isolation of powdery mildew resistance genes and development of valid molecular markers for pyramiding resistance genes in breeding programs is also discussed.  相似文献   

15.
Summary The current powdery mildew (Sphaerotheca fuligninea) resistant cucumber varieties suffer from leaf chlorosis during autumn, winter and early spring cultivation in the Netherlands. Therefore screening was carried out for novel powdery mildew resistance genes. From 177 accessions, derived from different sources, 108 accessions proved to be partially resistant to S. fuliginea. Crosses were made with 53 resistant accessions to distinguish the presence of novel genes. It is likely that the accessions C. sativus 2145, C. sativus LV 41, PI 188807, Vladivostokij, White and Yellow 1 have one or more recessive powdery mildew resistance genes, different from powdery mildew resistance genes of the line NPI, which was used for variety breeding. Powdery mildew resistance tests with S. fuliginea give similar results in different regions of the world.Abbreviations pmr powdery mildew resistance  相似文献   

16.
Fourty two barley lines direved from the F7 of crosses between barley cultivars and different accessions of Hordeum spontaneum collected in Israel and 30 lines or varieties with known genes for resistance to powdery mildew were included m this study. Eleven European and three Israeli powdery mildew cultures, possessing virulence genes corresponding to known resistance genes, were used to make comparisons between the varieties with known resistance genes and H. spontaneum derived lines. The reaction pattern of 39 H. spontaneum derived lines was clearly different from the reaction pattern o; any of the known genes for mildew resistance included in this study. Only two cases were observed in which the reaction pattern of H. spontaneum derived lines agreed with reaction patterns of known genes for mildew resistance viz. Ml-a9 and Ml-p. Trie Mildew resistance of one line apparently traces back to uncontrolled outcrossing with a Ml-a.6+Ml-g resistant cultivar. Since the majority of the 42 host genotypes tested showed distinctive variation in resistant reaction types against different mildew cultures, this study docs not support the assumption that differences in resistant infection types against distinct mildew cultures are sufficient to indicate the presence of supplementary genes for resistance in a given genotype of the host. The results justify the conclusion that the natural population of H. spontaneum in Israel forms a large gene pool for mildew resistance which is not yet used m cultivated barley.  相似文献   

17.
Summary Visual assessment, black & white image analysis and colour image analysis of the severity of powdery mildew (Sphaerotheca fuliginea) infection on leaves of cucumber (Cucumis sativus) were compared. The extent of infection with powdery mildew was expressed as the number of spores per cm2. Statistical treatment of the data showed colour image analysis to be superior to the other two methods of evaluation. Major veins, light reflections and variations in the colour of leaves can degrade the accuracy of colour image analysis somewhat. These problems are, however, surmountable. Colour image analysis qualifies as a valuable new tool for accurate, objective, reproducible and detailed quantitative assessment of disease on leaves of plants.Abbreviations H hue - I intensity - IA image analysis - PM powdery mildew - S saturation  相似文献   

18.
Summary Flower colour is the major contributor to the total ornamental value of a flower. The combination of biochemical knowledge and genetic engineering technology has resulted in the addition of a new colour to the existing colour range ofPetunia hybrida. This has been achieved by expression of the maize dihydroflavonol-4-reductase (DFR) gene in a suitable petunia acceptor which leads to the accumulation of pelargonidin-derived pigments in flowers. The resulting flower colour, however, was a pale brick-red, which is commercially unattractive in petunia. Our objective was to produce a product suitable for commercialisation by introducing the DFR gene into our breeding material via normal sexual recombination. Although the initial transformant exhibited many negative characteristics, first analyses indicated that it was feasible to obtain material for creating commercial hybrids. Experimental hybrids based on F4 lines were obtained with improved phenotypical expression of the orange flower colour in combination with a good general performance. In order to assess consumer-related characteristics, selected experimental hybrids were tested under field conditions. All transgenic plants had a normal appearance when compared to non-transgenic control plants. No linkage was observed between the transgenic trait and any negative characteristic. From these studies it can be concluded that through a combination of biochemistry, breeding and genetic engineering it is possible to generate unique flower colours in a cultivar with commercial potential.  相似文献   

19.
Elizabeth Keep 《Euphytica》1968,17(3):417-438
Summary The varieties Lloyd George and Burnetholm (and probably Malling Promise) are heterozygous for three genes governing resistance to mildew (S. macularis (FR.) Jaczewski, syn. S. humuli (DC.) BUrr.), Sp 1 and Sp 2 being dominant complementaries and sp 3 recessive. Resistance whether of Sp 1, Sp 2 or sp 3 sp 3 origin is epistatic to susceptibility. Sp 3 is linked with the fruit colour gene T with a crossover value of ca. 25%, the gene order in this linkage group being B-Sx 3-T-Sp3.Evidence suggesting linkage between H (hairy canes) and resistance is presented.  相似文献   

20.
Physocarpus opulifolius is a deciduous shrub native to North America belonging to the Spiraeoideae subfamily of the Rosaceae. The cultivars ‘Luteus’ and ‘Diabolo’ are grown in gardens for their ornamental foliage, golden and purple respectively. We developed a linkage map of P. opulifolius with a view to detecting markers for the leaf colour genes, which are under major gene control. A total of 162 molecular markers (128 RAPDs, 27 AFLPs, three RGA, three STS markers and one SSR) and the leaf colour genes Pur and Aur were scored in the Physocarpus progeny and used to create a linkage map covering 586.1 cM over nine linkage groups. There was an average of 18.2 markers per linkage group and a mean linkage group length of 65.1 cM. Both leaf colour genes were mapped. This is the first reported linkage map of a member of the Spireaeoideae and the mapping of a small number of transferable markers has demonstrated its utility to comparative mapping, which will complement existing comparative mapping efforts in other rosaceous subfamilies.  相似文献   

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