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1.
M. Rahim    C. C. Jan  T. J. Gulya 《Plant Breeding》2002,121(1):57-60
Sunflower downy mildew (SDM) caused by Plasmopara halstedii, is a major disease of sunflower. Eleven resistance genes have been identified, but allelic relationships among these genes are not clear. This study examined the inheritance and allelic relationships of genes conferring resistance to SDM races 1, 2 and 3 (virulence phenotypes 100, 300 and 700, respectively) and confirmed a twelfth resistance gene. Three USDA Plant Introductions, AMES 3235, PI 497250, and PI 497938, and three released lines, RHA 266, RHA 274 and DM‐2 were studied. RHA 266 has only the Pl1 gene for race 1 resistance. Digenic inheritance of resistance was found in AMES 3235, PI 497250, and RHA 274. These lines have the Pl1 and Pl12 genes, conferring resistance to race 1, and the Pl2 and Pl11 genes, conferring resistance to race 2. DM‐2 and PI 497938 have Pl12 (but not Pl1 for resistance to race 1, the Pl12 gene (but not the Pl2) for resistance to race 2, and Pl5 for resistance to race 3. These resistance genes will serve as a foundation for future gene designations and genetic diversity studies of resistance to SDM.  相似文献   

2.
Summary Resistance toMeliodogyne chitwoodi races 1 (MC1) and 2 (MC2) andM. hapla (MH) derived fromSolanum bulbocastanum was introduced into the cultivated potato gene pool through somatic fusion. The initial F1 hybrids showed resistance to the three nematodes. Resistance to reproduction on roots by MC1 was accompanied by resistance to tuber damage in F1 clones. Tuber damage sometimes occurred, however, in hybrids of BC1 progeny resistant to reproduction on roots when MC2 and MH were the challenging nematodes. Resistance to reproduction was transferred into BC1 individuals, but a greater proportion of BC1 progeny was resistant to MC1 than to MC2 or MH. Resistance to MC1 appears to be dominant and discretely inherited. F1 and BC1 progeny were pollen sterile, but seed were produced from crosses using cultivated tetraploid pollen sources. Approximately 11 and 33 per cent of pollinations produced berries on F1 and BC1 pistillate parents, respectively. Seed yield increased fourfold overall in crosses with F1 compared to BC1 individuals.Abbreviations MC1 Meloidogyne chitwoodi race 1 - MC2 Meloidogyne chitwoodi race 2 - MH Meloidogyne hapla - Rf Reproductive factor  相似文献   

3.
Sunflower lines RHA‐274, HA‐61 and RHA‐325 were studied for their resistance to race 330 of downy mildew (Plasmopara halstedii). The same inbred line, with normal (HA‐89) or sterile cytoplasm (cmsHA‐89) was used in all the crosses as susceptible parent, and, in each cross, only one genotype of the resistant parent was studied. The resistant‐to‐susceptible ratios obtained in the BC1 and F2 progenies from the crosses of the lines RHA‐274 and HA‐61 to cmsHA‐89 and HA‐89, respectively, suggested that, in each resistant line, two dominant genes are responsible for resistance to this downy mildew race. One of the genes (A) is epistatic to the other (B), and the recessive allele b in homozygosity is also epistatic to aa, with plants carrying aabb genotypes being resistant. Resistance to race 330 seemed to be controlled by two complementary genes in the sunflower inbred line RHA‐325, the dominant allele of one of them being present in cmsHA‐89. In the genotypes HA‐89 or cmsHA‐89, the existence of genes that modify the expected segregations following the crosses with resistant parents is proposed. It is concluded that, although major genes have been described as responsible for monogenic resistance to downy mildew, other types of regulation of this character, such as complementarity and epistatic relationships, do occur.  相似文献   

4.
Summary Interspecific substitutions of the nucleus of Helianthus annuus (2n=34) into the cytoplasm of H. petiolaris (2n=34) were obtained by successive backcrossing using cultivated sunflower, H. annuus, as the recurrent pollen parent.Meiosis in the F1 was characterized by multivalents, suggesting that 10 of the 34 chromosomes were heterozygous for chromosomal interchanges. An additional pair of chromosomes also contained a paracentric inversion. Continued backcrossing resulted in rapid elimination of the meiotic aberrations evident in the F1. In the BC1, 1 of 11 plants had normal meiosis and by the BC2, only 13 of 54 plants had meiotic aberrations similar to those of the F1. However, trisomic progeny (2n=35) were found in 3 of the 11 BC1 plants and 20 of the 54 BC2 plants. No meiotic aberrations were observed in BC3 or BC4 plants. Plants with indehiscent anthers, and considered to be male sterile (M.S.), first occurred in the BC1 and, by the BC2, 51 of 54 plants were M.S. All 19 BC3 and 16 BC4 plants were M.S. Preliminary investigations suggest that the pollen from such plants is sterile and that the sterility is cytoplasmic rather than genetic.Disc-flower measurements were a useful technique for selecting samples at the correct stage of microsporogenesis, but could not be used to distinguish between successive backcrosses.  相似文献   

5.
Inheritance of black leaf mold resistance in tomato   总被引：1，自引：0，他引：1  
Summary Inheritance of black leaf mold (BLM) (caused by Pseudocercospora fuligena) resistance was studied in four crosses involving two resistant Lycopersicon accessions (PI134417, L. hirsutum and PI254655, L. esculentum) and four susceptible Asian Vegetable Research and Development Center tomato lines (CLN657BC1F2-267-0-3-12-7, CL143-0-10-3-0-1-10, CLN698BC1F2-358-4-13 and CL5915-93D4-1-0-3). For each cross, six generations, i.e. P1, P2, F1, F2, BC1F1 and BC1F2 were evaluated following inoculations with isolate Pf-2 of P. fuligena. Chi-square analyses of the data based on the ratio of resistant to susceptible plants in the F2 in three of four crosses gave a good fit to a segregation ratio of 1 R : 15 S, and BC1F2 data in three of four crosses gave an acceptable fit to the segregation ratio of 1 R : 63 S. The results indicate that resistance to BLM may be conditioned by two recessive genes acting epistatically in both PI134417 and PI254655.  相似文献   

6.
A new race F of broomrape overcomes all known resistance genes in cultivated sunflower, but recently, sources of resistance against race F have been developed. The objective of the present research was to study the inheritance of resistance to race F in crosses between 12 resistant sunflower breeding lines, derived from three different sources of resistance, and the susceptible male‐sterile line P‐21. Parental lines and F1, F2, F3 and BC1 generations were evaluated for broomrape resistance. Segregations in the F2 and BC1 to resistant parent approached resistant to susceptible ratios of 1: 15 and 1: 3, respectively, in most of the crosses, suggesting a double dominant epistasis. However, segregations of 3: 13 and 1: 1 for F2 and BC1, respectively, indicating a dominant‐recessive epistasis, were also found. The F3 data confirmed these results. Owing to the recessive nature of this resistance, it must be incorporated into both parental lines for developing resistant hybrid cultivars.  相似文献   

7.
The main goal of this work was to introduce resistance genes for rust, caused by Uromyces appendiculatus, and anthracnose, caused by Colletotrichum lindemuthianum, in an adapted common bean cultivar through marker-assisted backcrossing. DNA fingerprinting was used to select plants genetically closer to the recurrent parent which were also resistant to rust and to race 89 of C. lindemuthianum. DNA samples extracted from the resistant parent (cv. Ouro Negro), the recurrent parent (cv. Rudá), and from BC1, BC2 and BC3 resistant plants were amplified by the RAPD technique. The relative genetic distances in relation to the recurrent parent varied between 9 and 59% for BC1, 7 and 33% for BC2, and 0 and 7% for BC3 resistant plants. After only three backcrosses, five lines resistant to rust and anthracnose with, approximately, 0% genetic distance in relation to the recurrent parent were obtained. These lines underwent field yield tests in two consecutive growing seasons and three of them presented a good yield performance, surpassing in that sense their parents and most of the reference cultivars tested.  相似文献   

8.
Two related segregating populations of Theobroma cacao L. were analysed for their resistance to Phytophthora palmivora. The first F1 population was obtained by crossing two susceptible cacao clones of Catongo (a highly homozygous genotype) and Pound 12(a highly heterozygous genotype) and the second population was obtained by backcrossing a single F1 tree with Catongo. The genetic maps obtained for each population were compared. The F1 map includes 162 loci and the backcross has 140 loci. The two maps, F1 and BC1, exhibit high co-linear loci organization covering respectively, 772 and 944 cM.Phytophthora resistance was assessed by measuring the size increase of a lesion at five (DL5)and ten days (DL10) after pod inoculation. Six different QTL were detected in the F1 and BC1 populations. One QTL was found in both populations, and appeared to be a major component of disease resistance, and explaining nearly 48% of the phenotypic variance in the F1 population. The absence of some yield QTL detection in the BC1 in comparison with the F1 population is due to the lack of transmission of the favouring alleles for these QTL from the single F1 tree used for the backcross. The phenotypic variance explained by the action of the quantitative trait alleles indicated that genetic factors of both major and minor effects were involved in the control of the character studied. QTL conferring increased resistance to Phytophthorawere identified in both susceptible parents, suggesting the presence of transgressive traits and the possibility of selection in cacao. Pleiotropic and epistatic effects for the QTL were also detected. Finally, the use of marker assisted selection (MAS) in cacao breeding programs is discussed. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

9.
Two transgenic Bt rice lines, KMD1 and KMD2, both containing a synthetic cry1Ab gene from Bt, were crossed with conventional rice varieties. The inheritance of resistance to SSB of KMD1 and KMD2was investigated through LSB and field examination of their progenies, e.g. F1, BC1 and F2 populations. In LSBs, 100.0% of newly hatched SSB larvae died on the second day after feeding on leaf tissues of F1 and GUS positive BC1 plants, of which the area of leaf tissues consumed by SSB is also similar to that of transgenic parents. These results imply that the resistance of Bt rice to SSB is dominantly controlled and could be easily exploited in hybrid rice production. Field evaluation showed that segregation ratios for SSB resistance to susceptibility in BC1 populations fit the ratio of 1:1, which was also confirmed by LSBs. However, in F2 populations, the ratio was significantly smaller than 3:1 for resistant to susceptible plants in all 6 indica × japonica (KMD1 and KMD2) crosses, though it fitted 3:1 in all 4 japonica × japonica crosses. The results implied that the resistance of Bt rice to SSB was controlled by a dominant gene which was present in a homozygous condition in both KMD1 and KMD2, but the inheritance could be affected by other factors. Assays for Cry1Ab protein showed that, in most crosses, the content of Cry1Ab is significantly higher in leaves of GUS positive F1, BC1 and F2 plants than that in transgenic Bt parent plants, which accounts for the high resistance observed in these plants to SSB. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

10.
Cucurbita moschata cv. Nigerian Local has been used as a source of resistance to Zucchini yellow mosaic virus (ZYMV), Watermelon mosaic virus (WMV), Papaya ringspot virus W (PRSV-W) and Cucumber mosaic virus (CMV) in breeding both Cucurbita moschata and Cucurbita pepo. We used the F1, F2 and BC1 generations derived from the cross C.-moschata cv. Waltham Butternut × Nigerian Local to study the inheritance of resistance to each of the viruses. We confirmed monogenic dominant resistance to ZYMV previously attributed to Zym, and we report monogenic dominant resistance to WMV and CMV which we propose to designate Wmv and Cmv, respectively. A single recessive gene, which we propose to designate prv, controls resistance to PRSV. DNA samples were extracted from a Waltham Butternut BC1 F1 population screened with ZYMV and analyzed using randomly amplified polymorphic DNA markers. No RAPD markers linked to ZYMV resistance were found. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

11.
Summary Two RAPD markers linked to gene for resistance (assayed as pustule number cm−2 leaf area) to rust [Uromyces fabae (Pers.) de Bary] in pea (Pisum sativum L.) were identified using a mapping population of 31 BC1F1 [HUVP 1 (HUVP 1 × FC 1] plants, FC 1 being the resistant parent. The analysis of genetics of rust resistance was based on the parents, F1, F2, BC1F1 and BC1F2 generations. Rust resistance in pea is of non-hypersensitive type; it appeared to be governed by a single partially dominant gene for which symbol Ruf is proposed. Further, this trait seems to be affected by some polygenes in addition to the proposed oligogene Ruf. A total of 614 decamer primers were used to survey the parental polymorphism with regard to DNA amplification by polymerase chain reaction. The primers that amplified polymorphic bands present in the resistant parent (FC 1) were used for bulked segregant analysis. Those markers that amplified consistently and differentially in the resistant and susceptible bulks were separately tested with the 31 BC1F1 individuals. Two RAPD makers, viz., SC10-82360 (primer, GCCGTGAAGT), and SCRI-711000 (primer, GTGGCGTAGT), flanking the rust resistance gene (Ruf) with a distance of 10.8 cM (0.097 rF and LOD of 5.05) and 24.5 cM (0.194 rF and a LOD of 2.72), respectively, were identified. These RAPD markers were not close enough to Ruf to allow a dependable maker-assisted selection for rust resistance. However, if the two makers flanking Ruf were used together, the effectiveness of MAS would be improved considerably.  相似文献   

12.
J. W. Scott  J. P. Jones 《Euphytica》1989,40(1-2):49-53
Summary Resistance to fusarium wilt, incited by Fusarium oxysporum (Schlecht.) f. sp. lycopersici (Sacc.) Snyder & Hansen race 3 in tomato (Lycopersicon esculentum Mill.) was discovered in LA 716, a L. pennellii accession. A resistant BC1F3 breeding line, E427, was developed from LA 716. E427 was crossed with the susceptible cv. Suncoast and F1, BCP1, BCP2 (to Fla 7155, a susceptible parent) F2, F3, and BCP2S1 seeds were obtained. Segregation for resistance following root dip inoculation over three experiments indicated a single dominant gene controlled resistance. Five of the 12 BCP1S1's segregated more susceptible plants, whereas one of the 12 segregated more resistant plants than expected (P<0.05). Three of 23 F3 lines segregated more susceptible plants than expected while 1 of the 23 had more resistant plants than expected (P<0.05). Segregation in all other lines fit expected ratios. Five of the 23 F3's were homozygous resistant which was an acceptable fit to expectations (P=0.1–0.5). The gene symbol I 3 is proposed for resistance to race 3 of the wilt pathogen. Deviations from expected ratios in data reported here and for other breeding lines indicate an effect of modifier genes and/or incomplete penetrance. Plant age at inoculation and seed dormancy did not affect results.Florida Agricultural Experiment Station Journal Series No. 8101.  相似文献   

13.
Several upland Japonica breeding lines, WAB450-11-1-3-P40-HB (Abbreviated as WAB450-11), WAB450-11-1-2-P61-HB (WAB450-13), WAB450-l-B-P-91-HB (WAB450-14), IRAT216, IRAT359, and IRAT104, possessing restoring ability for the Dian 1 type cms (cms-D) line Dianyu 1A were recently identified at Food Crops Research Institute, Yunnan Academy of Agricultural Sciences, P. R. China. In this study, the inheritance of restoring ability in these lines was characterized through the production of backcross populations to the male-sterile and maintainer Dianyu 1 lines. Each of the restorer lines was used to pollinate Dianyu 1A to form a F1 hybrid which was then backcrossed (1) with Dianyu 1B producing a BC1F1 population and (2) to the female parent Dianyu 1A producing a BC5F2 population. The lines were also crossed with the japonica restorer line C57, carrying the restorer gene Rf1 that was introgressed from indica, to form F1 hybrids, these hybrids were then testcrossed with Dianyu 1A to study the allelic relationship of their restorer genes to Rf1. The inheritance in these testcross populations indicated that the complete restoring ability of WAB450-11, WAB450-13, WAB450-14, IRAT216, IRAT359, and the partial restoring ability of IRAT104 were controlled by dominant genes, and the gene in WAB450-13, WAB450-14, and IRAT216 was allelic or identical to Rf1. When 136 SSR markers were used to score 143 BC1F1 individuals from Dianyu 1A/WAB450-13//Dianyu 1B, the japonica Rf1 allele was found to be located between RM171 and RM6100 on the long arm of chromosome 10, an interval corresponding to that known for the indica Rf1 allele. The distance between RM171 and Rf1 is 2.8 cM, and that between Rf1 and RM6100 is 4.9 cM. Similar linkage results were obtained from mapping 89 individuals of the corresponding BC5F2 population (Dianyu 1A/6/Dianyu 1A/WAB450-13).  相似文献   

14.
N. Inomata 《Euphytica》2003,133(1):57-64
The cytogenetic study was investigated in the intergeneric F1 hybrid, F2and backcross progenies (BC1). The plants used were Brassica juncea(2n=36) and Diplotaxis virgata(2n=18). Three intergeneric F1 hybrids between two species were produced through ovary culture. They showed 36 chromosomes. It might consist one genome of B. juncea and two genomes of D. virgata. The morphology of the leaves resembled that of B. juncea. The color of the petals was yellow that was like in D. virgata. The size of the petal was similar to that of B. juncea. The mean pollen fertility was15.3% and the chromosome associations in the first meiotic division were(0–1)IV+(0–2)III+(8–12)II+(12–20)I. Many F2 and BC1seeds were harvested after open pollination and backcross of the F1 hybrids withB. juncea, respectively. The F2seedlings showed different chromosome constitutions and the range was from 28 to54 chromosomes. Most seedlings had 38chromosomes followed by 36, 40 and 54. The BC1 seedlings also showed different chromosome constitutions and the range was from 29 to 62. Most seedlings had both 40and 54 chromosomes followed by 36, 46 and52. In the first meiotic division of F2 and BC1 plants, a high frequency of bivalent associations was observed in all the various kinds of somatic chromosomes. Many F3 and BC2 seeds were obtained by self-pollination and open pollination of both F2 and BC1 plants, and by backcrossing both F2 and BC1plants with B. juncea, respectively,especially, three type progeny with 36, 40or 54 chromosomes. The somatic chromosomes of the F3 and BC2 plants were further investigated. The bridge plants between B. juncea and D. virgata with 36 chromosomes may be utilized for breeding of other Brassica crops as well as B. juncea. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

15.
Summary Cajanus platycarpus, an incompatible wild species from the tertiary gene pool of pigeonpea (C. cajan (L.) Millspaugh), has many desirable characteristics for the improvement of cultivated varieties. To necessitate such transfers, embryo rescue techniques were used to obtain F1 hybrids. The F1 hybrids were treated with colchicine to obtain tetraploid hybrids, that were selfed to obtain F2, F3 and F4 progenies. All of the hybrids and subsequent progenies had an intermediate morphology between the two parents. Backcrossing of the tetraploid hybrids with cultivated pigeonpea was not possible given embryo abortion, with smaller aborted embryos than those obtained in the F0 parental cross.As a route of introgression, diploid F1 hybrids were backcrossed with cultivated pigeonpea and BC1 progeny obtained by in vitro culture of aborting embryos. BC2 plants were obtained by normal, mature seed germination. Although embryo rescue techniques had to be used to obtain F1 and BC1 plants, it was possible to produce BC2 and subsequent generations through direct mature seed. Every backcross to cultivated pigeonpea increased pollen fertility and the formation of mature seeds.Special project assistant till December, 2003.  相似文献   

16.
In this study, the inheritance of resistance to Beet necrotic yellow vein virus (BNYVV) in accessions Holly-1-4and WB42 was investigated. Crosses between both resistant sources and susceptible parents were carried out and F1F2 and BC1 populations were obtained. Virus concentrations in WB42and its F1 populations were lower than in Holly-1-4. Observed ratios of susceptible and resistant plants in segregating populations of Holly-1-4 as well as WB42 were in agreement with hypothesis of one dominant major gene. Segregation of plants in F2 populations obtained from crosses betweenHolly-1-4 and WB42 revealed that the resistance genes in Holly-1-4 and WB42 were nonallelic and linked loci. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

17.
Summary Strong resistance to the cane diseases Elsinoë veneta, Didymella applanata and Botrytis cinerea, and to Sphaerotheca macularis, occurred in F1 and BC1 derivatives of an accession of Rubus coreanus. Resistance to cane spot (E. veneta) was polygenic.In eight out of ten BC1 progenies, average grades for cane spot infections were significantly higher in white-flowered (an 1) than pink-flowered (An 1) plants and in hairy-caned (H) than in glabrous (h) seedlings. It is postulated that in R. coreanus factors controlling resistance are linked with An 1 and. probably, with h.Average grades for spur blight (D. applanata) were significantly higher in white-flowered plants in nine out of ten BC1 progenies. Spininess (S) was associated with greater susceptibility in six out of eight BC1 families, although this difference was not statistically significant.Plants with the phenotype hAn 1 on average provided the best source of resistance to both cane spot and spur blight.  相似文献   

18.
We have previously found an accession of Lycopersicon pimpinellifolium (Jusl.) Mill. (`TO-937') that appeared to resist attack by the two-spotted spider mite (Tetranychus urticae Koch). L. pimpinellifolium is a very close relative of the cultivated tomato (Lycopersicon esculentum Mill.) and thereby a potential source of desirable traits that could be introgressed to the crop species. The objective of this study was to investigate the genetics of the resistance present in `TO-937'. Resistance to infestation by the spider mite was quantified in 24-plant plots of L. pimpinellifolium accessions `TO-937' and `PE-10', L. pennellii accession `PE-45', L. esculentum cultivars `Moneymaker', `Roma' and `Kalohi' (reported to be partially resistant: Stoner & Stringfellow, 1967), and the interspecific F1 cross, L. esculentum `Moneymaker' × L. pimpinellifolium `TO-937'. Only `TO-937', the F1, and`PE-45' were found to be resistant. Resistance of `TO-937' was complete when evaluated in two small greenhouses completely planted with `TO-937' so as to simulate the genotypic homogeneity usual in commercial crops. Generations (P1, P2, F1, F2, BC1P1, and BC1P2) of a P1 (susceptible) × P2 (resistant) cross (`Moneymaker' × `TO-937') were studied for resistance in a single-plant per plot design. Resistance of `TO-937' was inherited with complete dominance and appeared to be controlled by either two or four genes according to whether segregation in the F2 or the BC1P1, respectively, were considered. However, calculation of the number of genes involved in the resistance was complicated by negative interplot interference due to the high frequency of resistant genotypes within most of the generations. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

19.
Summary Accessions of Hordeum vulgare ssp. spontaneum, the wild progenitor of barley, collected in Israel (70), Iran (15) and Turkey (6) were screened for seedling response to four isolates of Rhynchosporium secalis, the pathogen causing leaf scald in barley. Resistance was very common in the collection (77%) particularly among accessions from the more mesic sites (90%). The genetics of this resistance were investigated in fifteen backcross (BC3) lines that contained an isozyme variant from H.v. ssp. spontaneum in a H.v. ssp. vulgare (cv. Clipper) background and were resistant to scald. Segregation in the BC3F2 families conformed with a single dominant resistance gene in 9 of the 15 lines. Scald resistance and the isozyme marker were closely linked in three of the BC3-lines, loosely linked in four and unlinked in the remaining eight. Scald resistance genes were identified on barley chromosomes 1, 3, 4 and 6. Crosses between several of the scald resistant BC-lines together with the linkage data indicated that at least five genetically independent resistances are available for combining together for deployment in barley. The linkage of scald resistance in several BC3-lines to the isozyme locus Acp2 is of special interest as this locus is highly polymorphic in wild barley.  相似文献   

20.
Summary Three triticale lines, Siskiyou, M2A-Beagle, and OK 77842 have been reported to possess resistance to bacterial leaf streak caused by Xanthomonas campestris, pv. translucens (Xct.). The three resistant lines were crossed to susceptible lines and crossed with each other. F2, BC1-F1, BC2-F1 plants were inoculated with a mixture of two Xct strains. The segregation data indicate the presence of a single dominant gene in each of the three resistant lines to bacterial leaf streak. These three genes are either the same or closely linked herein designated as Xct1.  相似文献   

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