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1.
A set of 520 chickpea germplasm lines was screened under laboratory conditions using blotter paper technique for reaction to dry root rot caused by Rhizoctonia bataticola (Taub.) Butler. The lines PG06102, BG2094 and IC552137 were identified as resistant for dry root rot. Phenotyping the mapping population consisting of 129 F2:3 progeny derived from the cross L550 × PG06102 during 2013 winter indicated monogenic inheritance of dry root rot resistance. Fifty‐two of 381 simple sequence repeat (SSR) primers polymorphic between the two parents were used to genotype F2 resistant and susceptible bulks prepared on the basis of reaction of F2:3 progeny. Four markers differentiated the resistant and susceptible bulks. All the four polymorphic markers were then assayed on the entire F2 population. Linkage analysis using 129 F2 plants revealed that two markers ICCM0299 and ICCM0120b were co‐segregating with resistance to dry root rot. These two markers appeared to have additive effects on resistance and could be potentially utilized in dry root resistance breeding programme.  相似文献   

2.
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   

3.
S. P. Mishra    A. N. Asthana  Lallan  Yadav 《Plant Breeding》1988,100(3):228-229
Inheritance of Cercospora leaf spot resistance in mungbean was studied in 20 crosses involving crosses of resistant × susceptible, resistant × resistant, susceptible × susceptible lines. 3:1 ratio was observed in all 14 F2s involving resistant × susceptible parents. The inheritance of Cercospora leaf spot resistance is thus controlled by a single recessive gene. Our results are contradictory to observations of Thaklk et al. (1977 a, b) who found monogenic dominant inheritance of Cercospora leaf spot resistance in mungbean.  相似文献   

4.
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   

5.
A study was conducted under controlled environment conditions in a phytotron to determine the nature of the inheritance of resistance Helminthosporium leaf blight (HLB) in a synthetic hexaploid wheat line, ‘Chirya‐3’, against the isolate KL‐8 of Bipolaris sorokiniana from the major wheat growing region of India. Crosses were made between two susceptible lines ‘WH 147’ and ‘Chinese Spring’. Analyses of F1 and F2 populations of these two crosses (‘WH 147’בChirya‐3’ and ‘Chinese Spring’בChirya‐3’) showed that resistance against the isolate in ‘Chirya‐3’ was governed by two recessive genes functioning in a complementary interaction giving an F2 segregation pattern of 1 : 15 (resistant : susceptible). The segregation pattern of the resistant F2 progenies in F3 families from both crosses confirmed that two homozygous recessive genes were responsible for resistance to the isolate of Bipolaris sorokiniana in the synthetic line ‘Chirya‐3’. It is proposed that the genes be designated as hlbr1 and hlbr2.  相似文献   

6.
S. Kumar 《Plant Breeding》1998,117(2):139-142
The inheritance of resistance to Fusarium wilt (race 2) of chickpea was studied in a set of three crosses, i.e. ‘WR315’בC104’ (resistant × susceptible), ‘WR315’בK850’ (resistant × tolerant) and ‘K850’בGW5/7’ (tolerant × tolerant) in order to investigate the number of genes involved, their complementation and to find out whether resistant segregants are possible in a cross between two tolerant cultivars. Tests of F1, F2 and F3 generations of these crosses under controlled conditions at ICRISAT, Patancheru, India, indicated involvement of three loci (two recessive and one dominant alleles). The homozygous recessive form at the first two loci conferred resistance whereas susceptibility occurred when the first two loci were in the dominant form. A dominant allele at the third locus can complement the dominant alleles at the other two loci to confer tolerance. Occurrence of resistant segregants in a cross between two tolerant cultivars was observed.  相似文献   

7.
Fusarium root rot (FRR) is a major disease of common bean worldwide. Knowledge of the inheritance of resistance to FRR would be important in devising strategies to breed resistant varieties. Therefore, a 12 × 12 full diallel mating scheme with reciprocal crosses was performed to generate 132 F1 progenies, which were then advanced to the F3. The progenies were evaluated for resistance to FRR under green house conditions in Uganda. General combining ability (GCA) effects were highly significant (P ≤ 0.01) for disease scores. Specific combining ability effects were not significant (P > 0.05) in the F1, but were highly significant (P < 0.01) in the F3 generation. These results indicate that resistance to FRR was governed by genes with additive effects in combination with genes with non-additive effects. Reciprocal differences were also significant (P = 0.01) at F1 and F3, primarily reflecting a large influence of maternal effects in both these generations. In fact, susceptible parents did not differ significantly (P > 0.05) for disease scores when used as paternal parents in the F3, but differed strongly as maternal parents (P = 0.0002). Generally, the progenies were distinctly more resistant when the resistant parent was used as the female in crosses, especially as observed in the F3. The maternal effects were strong in the F3 generation, suggesting a complex form of cytoplasmic–genetic interaction. The non-maternal reciprocal effects in the F3 were significant (P < 0.05) in both the resistant × resistant diallel, and in the resistant × susceptible crosses. Mid-parent heterosis (MPH) occurred in most crosses, with average heterosis approximately equal in each of the three generations, indicating that epistasis was probably more influential than dominance of individual genes. Gene-number formulas indicated that several genes were involved in resistant × susceptible crosses. Among resistant × resistant crosses, many produced continuous distributions of F1 progeny scores, suggesting polygenic inheritance, while bi-modal distributions were characteristic of the F3 distributions, and fit expected ratios for two or three loci segregating in each cross. Dominant forms of epistasis favoring resistance were strongly indicated. Parent–offspring heritability estimates were moderate. Overall, the results indicate that resistant parents contain a number of different resistance genes that can be combined with the expectation of producing strong and durable resistance. The lines MLB-49-89A, MLB-48-89, RWR719 and Vuninkingi, with large and negative GCA effects, contributed high levels of resistance in crosses and would be recommended for use in breeding programs.  相似文献   

8.
European red clover (Trifolium pratense) crops are challenged by clover rot, a devastating disease caused by Sclerotinia trifoliorum or, in some cases by S. sclerotiorum. No completely resistant cultivars are available and resistance breeding is hampered by the lack of knowledge on the number of involved resistance genes and the heritability of clover rot resistance. In this study, we estimated the number of major genes contributing to clover rot resistance by analysing 15 F1 progeny populations from pair crosses between ramets of resistant and susceptible genotypes. Parent plants were chosen from diverse, diploid populations, including wild material, landraces and cultivars. Young progeny plants were inoculated with ascospores, evaluated phenotypically and the segregation of disease scores was studied. Our results indicated that clover rot resistance may be conferred by three major effect genes, although segregation patterns suggested that there may be numerous minor effect genes involved as well. No proof was found for a maternal inheritance of clover rot resistance. To get insight in the heritability of clover rot resistance, we applied divergent selection by our high-throughput bio-test on an experimental diploid population: the original population (70.5 %), the first generation after selection for susceptibility (79.2 %) and the first generation after selection for resistance (62.3 %) differed significantly in susceptibility (p < 0.001). The second generation after selection for resistance (60.0 %) was not more resistant than the first generation after selection for resistance. In the first generation of selection the heritability (h2) was on average 0.34. In the second generation of selection h2 was 0.07. These findings have important implications for resistance breeding.  相似文献   

9.
Six intervarietal crosses involving two resistant and three susceptible genotypes of mungbean were attempted with the objectives to determine the mode of inheritance of gene‐specific Mungbean Yellow Mosaic Virus (MYMV) resistance. An infector row technique along with artificial inoculation was used for evaluating parents, F1, F2 and F3 plants for MYMV resistance. Disease scoring for MYMV indicated that F1s were highly susceptible as were the susceptible parents while resistant parent exhibited resistant reaction. The F2 progeny segregated in the ratio of 9 S:3 MS:3 MR:1 R suggesting that the resistance was governed by digenic recessive genes (rm1 and rm2). When one gene (rm1) was present in the homozygous recessive condition in different plants, it conferred moderately susceptible (MS) reaction, whereas when other gene (rm2) was in homozygous condition, moderately resistant (MR) reaction was obvious. When both genes (rm1 and rm2) were present together in the homozygous recessive condition, resistant reaction (R) was observed. The F2 segregation explained on the basis of phenotypic expression was further confirmed by F3 segregation.  相似文献   

10.
Summary Black rot disease caused by Xanthomonas campestris pv. campestris is a limiting factor in the commercial production of the cauliflower crop. Crosses were attempted between SN 445, a mid season cultivar resistant to black rot and two highly susceptible commercial cultivars (Pusa Snowball-1 and K-1). Studies of the F1's, F2's and back crosses indicated that SN 445, carries a dominant gene imparting resistance to black rot.  相似文献   

11.
A set of 21 monosomic (2n ‐ 1) and the disomic (2n) lines of the ‘Chinese Spring’ cultivar were crossed with ‘Chirya‐3′, the CIMMYT synthetic wheat line which has been identified as highly resistant for Helminthosporium leaf blight disease (HLB), in order to locate the genes governing disease resistance. The F1 and segregating populations were challenged and screened against the most virulent pure mono‐conidial HLB isolate KL‐8 (Karnal, India). The F1 progenies of the crosses were found to be susceptible because of the recessive nature of resistance. The F2 progeny of the control cross (‘Chinese Spring’בChirya‐3’), segregated in the ratio of 1: 15 (resistant: susceptible), indicating that resistance to HLB was controlled by a pair of recessive genes. While the F2 progeny of 19 monosomic crosses segregated in the ratio of 1: 15 (resistant: susceptible), the progeny of the remaining two crosses, 7B and 7D, deviated significantly from the ratio, revealing that 7B and 7D were the critical chromosomes for resistance genes that were located one on each chromosome. Moreover, the critical lines, 7B and 7D, confirmed the digenic complementary recessive nature of gene action by fitting well with the overall pooled F2 segregation ratio of 13: 51 (resistant: susceptible) as expected for digenic complementary recessive resistance. The F3 segregation ratios of the critical crosses, based on their pooled F2 analysis, was estimated as 19: 32: 13 (non‐segregating susceptible: segregating as susceptible and resistant: non‐segregating resistant). F3 progenies when tested with these ratios showed goodness‐of‐fit, confirming that the two pairs of recessive resistance genes were located on chromosomes 7B and 7D.  相似文献   

12.
A. N. Mishra    K. Kaushal    S. R. Yadav    G. S. Shirsekar    H. N. Pandey 《Plant Breeding》2005,124(5):520-522
Recessively inherited gene Sr2 has provided the basis of durable resistance to stem rust (caused by Puccinia graminis tritici) in wheat (Triticum aestivum L.) worldwide. The associated earhead and stem melanism or ‘pseudo‐black chaff’ is generally used as a marker for this gene. Sr2 has been postulated in many wheat cultivars of India including ‘Lok 1’, based on associated pseudo‐black chaff in adult plants, and leaf chlorosis in seedlings. However, dominant inheritance of the resistance factor operating in ‘Lok 1’, and a 13 : 3 (resistant : susceptible) F2 segregation in the ‘Sr2‐line’ (‘Chinese Spring’6 × ‘Hope’ 3B) × ‘Lok 1’ cross confirmed that Sr2 was absent in ‘Lok 1’. Susceptible plants with a pseudo‐black chaff phenotype were observed in F2 populations of ‘Agra Local’ (susceptible) × ‘Lok 1’, and the ‘Sr2‐line’ × ‘Lok 1’ crosses. Most of the F3 families derived from the susceptible F2 segregants with pseudo‐black chaff phenotypes were true breeding for the expression of pseudo‐black chaff with susceptibility to stem rust. Thus, linkage of pseudo‐black chaff with Sr2 in wheat can be broken, and hence, caution may be exercised in using pseudo‐black chaff as a marker for selecting Sr2 in breeding programmes.  相似文献   

13.
M. Heun  G. Fischbeck 《Plant Breeding》1989,103(3):262-264
The inheritance of the Mlk powdery mildew resistance originating from ‘Heine 2174.50’ was analyzed by crossing the Mlk resistant cultivar ‘Ralle’× cv. ‘Amor’ (highly susceptible) and vice versa and by observing the reactions of F1- and F2-plants after inoculation with two different Mlk avirulent powdery mildew isolates. In all cases, a 3 (resistant): I (susceptible) segregation was found in F2. The reactions of the F2plants against the two powdery mildew isolates were identical in each case. Therefore, it is supposed that one dominant resistant gene is responsible for the resistant reactions against these two isolates. These results support the earlier assumption of Heun and Fischbeck (1987b) that the whole Mlk resistance pattern is controlled by a single gene.  相似文献   

14.
Y. N. Bai  J. Y. Gai 《Euphytica》2005,145(1-2):25-32
At present, no report on inheritance of male fertility restoration has been released, yet more than 10 cytoplasmic-nuclear male-sterile soybean lines as well as their maintainers and restorers have been developed. Based on our previous work, 25 restorers for the male-sterile line NJCMS1A were identified and the inheritance of male fertility restoration for these restorers was studied. The results showed that F1s between NJCMS1A and its restorers were completely male-fertile. The numbers of fertile and sterile plants in the F2 population of Cross I (NJCMS1A × N23601) and Cross II (NJCMS1A × N23683) corresponded to a segregation ratio of 15:1, and the numbers of non-segregation lines, 3:1 segregation lines and 15:1 segregation lines in F2:3 of the same two crosses fitted a 7:4:4 genotypic segregation ratio. The testcross BC1F1s between the F1s of the above two crosses and NJCMS1A, NJCMS1B showed a 3:1 segregation ratio. Accordingly, it was inferred that two pairs of duplicate dominant genes controlled the male fertility restoration of NJCMS1A in both crosses. Meanwhile, F2 of other 23 crosses between NJCMS1A and its 23 restorers showed a fertility segregation ratio of 3:1 or 15:1. The F1s of the five testcrosses between NJCMS1A and the F1s of five crosses selected from the above 23 crosses showed that fertility segregation was 3:1 in BC1F1s between NJCMS1A and F1s of the crosses of which fertility segregation fitted 15:1 in F2 population, while fertility segregation in BC1F1s was 1:1 for those fertility segregation fitted 3:1 in F2 population. Allelism tests showed that restore genes of all restorers in the experiment were allelic to two pairs of dominant genes. All results showed that some restorers bore one pair of dominant restore gene and the others bore two pairs of duplicate dominant gene. The mechanism of F1 male sterility of the cross N8855 × N2899 was discussed.  相似文献   

15.
An experiment was conducted to study the genetics and nature of gene action of resistance to watermelon bud necrosis orthotospovirus (WBNV) in watermelon. The experimental materials comprised of two resistant (BIL‐53 and IIHR‐19) and one susceptible (IIHR‐140) parents. Each of the resistant parents was crossed with the susceptible parent to develop six generations (P1, P2, F1, F2, BC1 and BC2) to study genetics. The results of segregation in F2 and backcross progenies suggested that resistance is governed by a major dominant gene along with other background minor genes in both the crosses. BIL‐53 was found to possess higher degree of resistance with simple inheritance and hence may be of interest to breeders. Simple selection can be effective for improving the trait in the cross BIL‐53 × IIHR‐140 as additive gene action is prevalent.  相似文献   

16.
Summary The inheritance of resistance to Nasonovia ribis nigri in L. sativa was investigated. Parents and F1 and F2 populations from crosses between the susceptible cultivar Ravel and two resistant breeding lines were tested. In both breeding lines one dominant gene appeared responsible for resistance.  相似文献   

17.
The genetics of resistance to Phomopsis stem blight caused by Diaporthe toxica Will., Highet, Gams & Sivasith. in narrow-leafed lupin (Lupinus angustifolius L.) was studied in crosses between resistant cv. Merrit, very resistant breeding line 75A:258 and susceptible cv. Unicrop. A non-destructive glasshouse infection test was developed to assess resistance in the F1, F2, selected F2-derived F3 (F2:3) families, and in selfed parent plants. The F1 of Unicrop × 75A:258 (and reciprocal cross) was very resistant, and the F2 segregated in a ratio of 3:1 (resistant: susceptible), which suggested the presence of a single dominant allele for resistance in 75A:258. In Merrit × Unicrop (and reciprocal), the F1 was moderately resistant, and the F2 segregated in a ratio of 3:1 (resistant: susceptible). Thus Merrit appeared to carry an incompletely dominant resistance allele for resistance. The F1 of Merrit × 75A:258 (and reciprocal) was very resistant and the F2 segregated in a ratio of 15:1 (resistant: susceptible), which supported the existence of independently segregating resistance alleles for resistance in 75A:258 and Merrit. Alleles at loci for early flowering (Ku) and speckled seeds (for which we propose the symbol Spk) segregated normally and independently of the resistance alleles. Resistant F2 plants gave rise to uniformly resistant or segregating F2:3 families, whereas susceptible F2 plants gave rise only to susceptible F2:3 families. However, the variation in resistance in the F2 and some F2:3 families of crosses involving 75A:258, from moderately to extremely resistant, was greater than that expected by chance or environmental variation. We propose the symbols Phr1 to describe the dominant resistance allele in 75A:258, and Phr2 for the incompletely dominant resistance allele in Merrit. Phr1 appears to be epistatic to Phr2, and expression of Phr1 may be altered by independently segregating modifier allele(s). This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

18.
J. Rubio    E. Hajj-Moussa  M. Kharrat    M. T. Moreno    T. Millan  J. Gil 《Plant Breeding》2003,122(2):188-191
The inheritance of resistance to fusarium wilt race 0 of chickpea and linked random amplified polymorphic DNA (RAPD) markers were studied in two F6:7 recombinant inbred line (RIL) populations. These RILs were developed from the crosses CA2156 × JG62 (susceptible × resistant) and CA2139 × JG62 (resistant × resistant), and were sown in a field infected with fusarium wilt race 0 in Beja (Tunisia) over 2 years. A1:1 resistant to susceptible ratio was found in the RIL population from the CA2156 × JG62 cross, indicating that a single gene with two alleles controlled resistance. In the second RIL population (CA2139 × JG62) a 3:1 resistant to susceptible ratio indicated that two genes were present and that either gene was sufficient to confer resistance. Linkage analysis showed a RAPD marker, OPJ20600, linked to resistance in both RIL populations, which is present in the resistant parent JG62.  相似文献   

19.
Summary Pea blight caused by Assochyta pinodella does considerable damage to the pea crop every year. To ascertain the inheritance of resistance to pea blight and incorporate resistance in the commercial cultivars, crosses were made between Kinnauri resistant to pea blight and four highly susceptible commercial pea cultivars — Bonneville, Lincoln, GC 141 and Sel. 18. Studies of the F1's, F2's, back crosses and F3's indicated that Kinnauri carries a dominant gene imparting resistance to pea blight.  相似文献   

20.
The peach root‐knot nematode, Meloidogyne floridensis (MF), infects majority of available nematode‐resistant peach rootstocks which are mostly derived from peach (Prunus persica) and Chinese wild peach (P. davidiana). Interspecific hybridization of peach with its wild relative, Kansu peach (P. kansuensis), offers potential for broadening the resistance spectrum in standard peach rootstocks. We investigated the inheritance of resistance to MF in segregating populations of peach (‘Okinawa’ or ‘Flordaguard’) × P. kansuensis. A total of 379 individuals from 13 F2 and BC1F1 families were challenged with a pathogenic MF isolate “MFGnv14” and were classified as resistant (R) or susceptible (S) based on root galling intensity. Segregation analyses in F2 progeny revealed the involvement of a major locus with a dominant or recessive allele determining resistance in progeny segregating 3R:1S and 1R:3S, respectively. Testcrosses with a homozygous‐susceptible peach genotype (‘Flordaguard’ or ‘UFSharp’) confirmed P. kansuensis as a source of new resistance and the heterozygous allelic status of P. kansuensis at the locus conferring resistance to MF. We propose a single‐locus dominant/recessive model for the inheritance of resistance.  相似文献   

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