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1.
The mode of inheritance and allelic relationships among genes conferring resistance to Karnal bunt were studied in seven bread-wheat (six resistant and one susceptible) genotypes. The resistant genotypes originated in China (‘Shanghai#8’), Brazil (PF71131), the USA (‘Chris’), and Mexico (‘Amsel’, CMH77.308 and ‘Pigeon’). The susceptible line WL711 was from India. Evaluation of these wheat lines and all possible crosses among their F1 and F3 generations (about 100 progenies in each cross) revealed that two partially recessive genes conferred the resistance to Karnal bunt in ‘Pigeon’, whereas four partially dominant genes were present in the other genotypes. ‘Chris’, ‘Amsel’ and PF71131 carry one gene, whereas ‘Shanghai#8’ and CMH77.308 have two genes. ‘Chris’, ‘Amsel’, and PF71131 have different genes, whereas one gene was common to PF71131, CMH77.308 and ‘Shanghai#8’, and another to ‘Chris’ and CMH77.308. Gene symbols were formally designated to the resistant stocks. Resistance was incomplete and stable.  相似文献   

2.
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   

3.
C. He  G. R. Hughes 《Plant Breeding》2003,122(4):375-377
Common bunt caused by Tilletia tritici and T. laevis has occurred worldwide and reduces yield and quality in common and durum wheats. The development of DNA markers linked to bunt resistance to race T1 in the cross, ‘Laura’(S) בRL5407’ (R), was carried out in this study based on the single head derived F4:5 and single seed derived F4:6 populations. Bulked segregant analysis was used to identify two random amplified polymorphic DNA (RAPD) markers linked to the gene for resistance to race T1 in the spelt wheat ‘RL5407′. The two markers identified, UBC548590 and UBC274988, flanked the resistance gene with a map distance of 9.1 and 18.2 cM, respectively. The former was linked in repulsion phase to bunt resistance while the later was in coupling phase. The two RAPD markers and the common bunt‐resistance gene all segregated in Mendelian fashion. Use of these two RAPD markers together could assist in incorporating the bunt‐resistance gene from spelt wheat into common wheat cultivars by means of marker‐assisted selection.  相似文献   

4.
Summary An analyis of an F1-based incomplete diallel was conducted involving 11 parents with different levels of resistance to Karnal bunt (Tilletia indica (Mitra)). It demonstrated that general combining ability (GCA) and thus additive or additive × additive gene effects were very important in the inheritance of resistance, accounting for 86.9% of the variation. Further analysis concentrated on F3 lines derived from individual random F2 plants from crosses with resistant varieties having the highest negative GCA effects. It was shown that the varieties Weaver and W499 have single dominant genes of resistance, which are different from each other, and which differ from a single allelic gene in varieties K342 and Cruz Alta. The majority of the crosses did not demonstrate a relationship between Karnal bunt infection and the number of days to heading. Resistant F3 lines varied in the number of days to heading from 80 to 100.  相似文献   

5.
The Russian wheat aphid (RWA), Diuraphis noxia (Mordvilko), has become a serious, perennial pest of wheat (Triticum aestivum L.) in many areas of the world. This study was initiated to determine the inheritance of RWA resistance in PI 140207 (a RWA-resistant spring wheat) and to determine its allelic relationship with a previously reported RWA resistance gene. Crosses were made between PI 140207 and ‘Pavon’ (a RWA-susceptible spring wheat). Genetic analysis was performed on the parents, F1, F2, backcross (BC) population and F2-derived F3 families. Analyses of segregation patterns of plants in the F1, F2, and BC populations, and F2-derived F3 families indicated single dominant gene control of RWA resistance in PI 140207. Results of the allelism test indicated that the resistance gene in PI 140207, while conferring distinctly different seedling reactions to RWA feeding, is the same as Dn 1, the resistance gene in PI 137739.  相似文献   

6.
Twelve synthesized ainphiplonds involving Karnal bunt (Neovossia indica)-resisiant accessions of Triticum monococum, T. boeoticum and Aegilops sqiwrrosa and susceptible but otherwise well adapted and high yielding T. Durum cultiviars were evaluated for Karnal bunt resisiance under artificial inoculation conditions. All ihe synthetic amphiploids, except DWI. 5031 x T. monocoirtum aniphlploid, were free from Karnal bunt disease indicating that the Karnal bunt resistance or T. motsococcum, T. boeoticMrn and Ae, squarrosa is expressec in the presence of the dnrum complement. The importance and utilization of the amphiploids fox breeding wheat varieties resistant to karnal bunt are discussed.  相似文献   

7.
Summary Karnal bunt caused by Tilletia indica in wheat seriously affects the quality of the grains. It is important to generate information on the genetics of resistance to this pathogen so as to aid resistance breeding. For this purpose, four Karnal bunt-resistant lines from China, Brazil and CIMMYT (International Maize and Wheat Improvement Center) and a susceptible Indian cultivar, WL711, were used. The parents, F1 and F3 progenies of five parental diallel crosses revealed that independently segregating loci with three partial dominant resistance alleles were involved in the resistance of Karnal bunt. Lines RC7201/2*BR2 and Roek//Maya/NAC carried one locus for resistance while Shanghai#7 and Aldan/IAS58 have two and three loci, respectively. One common locus was present in all four resistant parents, which imparted a high level of resistance.  相似文献   

8.
Six blast‐resistant pearl millet genotypes, ICMB 93333, ICMB 97222, ICMR 06444, ICMR 06222, ICMR 11003 and IP 21187‐P1, were crossed with two susceptible genotypes, ICMB 95444 and ICMB 89111 to generate F1s, F2s and backcrosses, BC1P1 (susceptible parent × F1) and BC1P2 (resistant parent × F1) for inheritance study. The resistant genotypes were crossed among themselves in half diallel to generate F1s and F2s for test of allelism. The F1, F2 and backcross generations, and their parents were screened in a glasshouse against Magnaporthe grisea isolates Pg 45 and Pg 53. The reaction of the F1s, segregation pattern of F2s and BC1P1 derived from crosses involving two susceptible parents and six resistant parents revealed the presence of single dominant gene governing resistance in the resistant genotypes. No segregation for blast reaction was observed in the F2s derived from the crosses of resistant × resistant parents. The resistance reaction of these F2s indicated that single dominant gene conferring resistance in the six genotypes is allelic, that is same gene imparts blast resistance in these genotypes to M. grisea isolates.  相似文献   

9.
Summary Studies were conducted to determine the inheritance and allelic relationships of genes controlling resistance to the Russian wheat aphid (RWA), Diuraphis noxia (Mordvilko), in seven wheat germplasm lines previously identified as resistant to RWA. The seven resistant lines were crossed to a susceptible wheat cultivar Carson, and three resistant wheats, CORWA1, PI294994 and PI243781, lines carrying the resistance genes Dn4, Dn5 and Dn6, respectively. Seedlings of the parents, F1 and F2 were screened for RWA resistance in the greenhouse by artificial infestation. Seedling reactions were evaluated 21 to 28 days after the infestation using a 1 to 9 scale. All the F1 hybrids had equal or near equal levels of resistance to the resistant parent indicating dominant gene control. Only two distinctive classes were present and no intermediate types were observed in the F2 segregation suggesting major gene actions. The resistance in PI225262 was controlled by two dominant genes. Resistance in all other lines was controlled by a single dominant gene. KS92WGRC24 appeared to have the same resistance gene as PI243781 and STARS-9302W-sib had a common allele with PI294994. The other lines had genes different from the three known genes.  相似文献   

10.
Inheritance of Karnal bunt-free trait in bread wheat   总被引:1,自引:0,他引:1  
A Karnal bunt (KB)‐free wheat stock (‘KBRL22’) obtained from a cross of two resistant lines (‘HD29’ and ‘W485’) was used as a donor to introgress the KB‐free trait into ‘PBW343’(an ‘Attila’ sib), the most widely grown wheat cultivar in India. The number of KB‐free and KB‐affected plants in BC 1, BC2, BC3 and BC4 as well the F2 was recorded after artificial inoculations. The segregation pattern in these generations clearly indicated two independently segregating, dominant genes which jointly confer the KB‐free attribute. The importance of the KB‐free line generated in this experiment is discussed.  相似文献   

11.
The inheritance of siliqua orientation and seed coat colour in Brassica tournefortii was investigated using four genotypes varying in these two characters. The F1, F2 and backcross generations of two crosses were used for studying the segregation pattern of the traits. The plants were classified for seed colour as having brown or yellow seeds and for siliqua orientation as having upright, semi‐spread or spread siliqua. Seed colour was found to be under monogenic control with brown being dominant over yellow. Siliqua orientation was under digenic polymeric gene action: upright siliqua was produced by the presence of two dominant genes and spread siliqua by two recessive genes. The absence of even a single dominant gene resulted in a third type of siliqua orientation, semi‐spread siliqua.  相似文献   

12.
Summary The genetics of resistance to angular leaf spot caused by Pseudomonas syringae pv. tabaci in Nicotiana tabacum cultivars Burley 21 and Kentucky 14 was investigated by studying disease reactions to three isolates of parental, F1, F2 and backcross generations derived from crosses between the resistant cultivars and the susceptible cultivar Judy's Pride. Studies were conducted in the greenhouse and in field plant beds. Chi-square values were computed to determine whether the observed ratios for disease reactions deviated from expected Mendelian ratios for a single, dominant gene controlling resistance to angular leaf spot in tobacco. Based on the resistance of the F1 and the backcross generation to the resistant parent (BC-R), a 3 resistant: 1 susceptible segregation ratio in the F2, and a 1 resistant: 1 susceptible segregation ratio in the backcross generation to the susceptible parent (BC-S), it was concluded that resistance to three isolates of Pseudomonas syringae pv. tabaci is governed by a single, dominant gene.  相似文献   

13.
P. K. Singh  G. R. Hughes 《Euphytica》2006,152(3):413-420
The fungus Pyrenophora tritici-repentis, causal agent of tan spot of wheat, produces two phenotypically distinct symptoms, tan necrosis and extensive chlorosis. The inheritance of resistance to chlorosis induced by P. tritici-repentis races 1 and 3 was studied in crosses between common wheat resistant genotypes Erik, Hadden, Red Chief, Glenlea, and 86ISMN 2137 and susceptible genotype 6B-365. Plants were inoculated under controlled environmental conditions at the two-leaf stage and disease rating was based on presence or absence of chlorosis. In all the resistant × susceptible crosses, F1 plants were resistant and the segregation of the F2 generation and F3 families indicated that a single dominant gene controlled resistance. Lack of segregation in a partial diallel series of crosses among the resistant genotypes tested with race 3␣indicated that the resistant genotypes possessed␣the same resistance gene. This resistance gene was effective against chlorosis induced by P.␣tritici-repentis races 1 and 3.  相似文献   

14.
N. Kedar  Nira Retig  J. Katan 《Euphytica》1967,16(2):258-266
Significant deviations from the ratios expected, according to the single dominant gene hypothesis for resistance to Fusarium wilt, were found in crosses involving several susceptible and resistant tomato lines. The susceptible class was the deficient one in F2 and F3 populations, as well as in backcrosses in which the heterozygotic resistant F1 served as the male parent. The reciprocal backcross, with the F1 as the female and the homozygous susceptible as the male, gave segregations better approximating or consistent with the single gene hypothesis. Reciprocal F1 and F2 generations did not give any evidence of cytoplasmic effects.The results were interpreted assuming preferential fertilization of ovules by pollen grains carrying the dominant I allele for resistance.The practical implications of the phenomenon of preferential fertilization in breeding for Fusarium resistance are discussed.  相似文献   

15.
H. Dong    J. S. Quick  Y. Zhang 《Plant Breeding》1997,116(5):449-453
The Russian wheat aphid (RWA), Diuraphis noxia (Mordvilko) has caused serious reduction in wheat production in 17 Western states of the United States since 1986. Inheritance of resistance to RWA in seven wheat lines and the allelism of the resistance genes in these lines with three known resistance genes Dn4, Dn5, and Dn6 were studied. The seven resistant lines were crossed to a susceptible wheat cultivar ‘Carson’ and three resistant wheats: CORWA1 (Dn4), PI 294994 (Dn5), and PI 243781 (Dn6). Seedlings of the parents, F1, and F2 were screened for RWA resistance in the greenhouse by artificial infestation. Seedling reactions were evaluated 21–28 days after the infestation using a 1–9 scale. The resistance level of all the F1 hybrids was similar to that of the resistant parent, indicating dominant gene control. Only two distinctive classes were present and no intermediate types were observed in the F2 population, suggesting qualitative, nonadditive gene action, in which the presence of any one of the dominant alleles confers complete resistance to RWA. Resistance in CI 2401 is controlled by two dominant genes. Resistance in CI 6501 and PI 94365 is governed by one dominant gene. Resistance in PI 94355 and PI 151918 may be conditioned by either one dominant gene or one dominant and one recessive gene. No conclusion can be made on how many resistance genes are in AUSVA1-F3, since the parent population was not a pure line. Allelic analyses showed that one of resistance genes in CI 2401 and PI 151918 was the same allele as Dn4, the resistance gene in CI 6501 was the same allele as Dn6, and AUS-VA1-F3 had one resistance gene which was the same allele as one of the resistance genes in PI 294994. One non-allelic resistance gene different from the Dn4, Dn5, and Dn6 genes in CI 2401, PI 94355, PI 94365, and PI 222668 was identified and should be very useful in diversifying gene sources in wheat breeding.  相似文献   

16.
S. Gupta    R. G. Saini  A. K. Gupta 《Plant Breeding》1995,114(2):176-178
Genetic analysis of leaf-rust resistance was conducted on two durum wheats. Triticum durum cvs. ‘PBW 34’ and ‘DWL 5023’ were crossed with the leaf-rust-susceptible durum wheat ‘Malvi Local’. The F1, F2 and F3 generations were tested against leaf-rust pathotypes 1, 77A and 108. In ‘PBW 34’, a single dominant gene was effective against each of the pathotypes 1 and 108, whereas two independently inherited dominant genes were effective against pathotype 77A. In ‘DWL 5023’, two independently inherited dominant genes were operative against pathotypes 1 and 77A, whereas a single dominant gene was identified as being operative against pathotype 108. Allelic tests on F2 generation and joint segregation analysis on F3 generation seedlings, suggested that two different genes in each cultivar are effective against these three leaf-rust pathotypes. Cultivar ‘PBW 34’ has Lrd1 and Lrd2 genes whereas Lrd1 and Lrd3 genes are present in ‘DWL 5023’.  相似文献   

17.
M. T. Assad 《Plant Breeding》2002,121(2):180-181
The Russian wheat aphid (RWA), Diuraphis noxia (Mordvilko), is a major economic pest of small grains in many countries. An experiment was therefore conducted to determine the inheritance of gene(s) controlling resistance to RWA in a resistant tetraploid durum wheat line. This resistant line,‘1881′, was crossed to a susceptible line, ‘Orejy‐e‐Kazeroon’, and then F1 F2 and BCF1 (backcross to susceptible line) seedlings were screened in a greenhouse for RWA resistance following artificial infection. Resistance in ‘1881’ was apparently controlled by one dominant gene. Since Dnl, Dn2, dn3, Dn4 and Dn5 have been reported to be located on genome D, it was reasoned that the resistance gene in ‘1881’ is not allelic to them.  相似文献   

18.
Wheat streak mosaic (WSM) caused by wheat streak mosaic virus (WSMV) is a serious disease of wheat and many plants in the grass family. In previous studies genotypes collected from different parts of Iran, were screened for WSM resistance. Two resistant genotypes, “Adl Cross” and “4004” were crossed to one susceptible genotype “Marvdasht.” Reciprocal crosses were also made. Seedlings of parents, F1, F2, backcrosses to susceptible (BCS) and resistant (BCR) were evaluated for WSMV reaction based on scales 0–7, by artificial infection under greenhouse conditions. Allelism was studied by evaluating the F1 and F2 seedlings of the resistant × resistant cross. Inheritance of resistance to WSMV in Adl Cross and 4004 was controlled by one dominant gene. No allelism was observed between resistance genes. Among the F2 seedlings of the resistant × resistant cross relatively more resistant genotypes with a zero score were observed. These two genes, therefore, can be incorporated into an adapted wheat cultivar to produce a more durable resistance.  相似文献   

19.
J. A. Kolmer    L. M. Oelke    J. Q. Liu 《Plant Breeding》2007,126(2):152-157
A genetic analysis of the landrace‐derived wheat accessions Americano 25e, Americano 26n, and Americano 44d, from Uruguay was conducted to identify the leaf rust resistance genes present in these early wheat cultivars. The three cultivars were crossed with the leaf rust susceptible cultivar ‘Thatcher’ and approximately 80 backcross (BC1) F2 families were derived for each cross. The BC1F2 families and selected BC1F4 lines were tested for seedling and adult plant leaf rust resistance with selected isolates of leaf rust, Puccinia triticina. The segregation and infection type data indicated that Americano 25e had seedling resistance genes Lr3, Lr16, an additional unidentified seedling gene, and one adult plant resistance gene that was neither Lr12 nor Lr13, and did not phenotypically resemble Lr34. Americano 26n was postulated to have genes Lr11, Lr12, Lr13, and Lr14a. Americano 44d appeared to have two possibly unique adult plant leaf rust resistance genes.  相似文献   

20.
Summary Two blue-mold resistant cultivars of Nicotiana tabacum L. were crossed with each other and with the susceptible Israeli local cultivar Mikhal. F1, F2 and F3 progenies of these crosses, F1 and F2 of backcrosses and the parental varieties were grown in a series of experiments, in which the seedlings were exposed to heavy natural infection with Peronospora tabacina Adam. The genetic basis of resistance was found to be identical in the two resistant strains Bel-61-10 and Chemical mutant. A single dominant major gene determined the segregation of resistance versus susceptibility in the crosses of these strains with Mikhal. The level of resistance of resistant segregates was shifted by environment and by quantitatively modifying genes. The index of resistance, which was calculated as a weighted mean of the degree of blue-mold expression of the resistant segregates, differed in the generations of cross progeny. This could be explained by the different expected levels of the modifying genes in these generations. Heritability of the index of resistance was calculated by parent-offspring regression and it was found to be 0.542 in the F3 and 0.227 in F2 backcross progenies.  相似文献   

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