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1.
Summary In studies of the inheritance of resistance, pea seedlings of seven lines in which stems and leaves were both resistant to Mycosphaerella pinodes were crossed with a line in which they were both susceptible. With seven of the crosses resistance was dominant to susceptibility. When F2 progenies of five crosses were inoculated on either stems or leaves independently, phenotypes segregated in a ratio of 3 resistant: 1 susceptible indicating that a single dominant gene controlled resistance. F2 progenies of one other cross gave ratios with a better fit to 9 resistant: 7 susceptible indicating that two co-dominant genes controlled resistance. The F2 progeny of another cross segregated in complex ratios indicating multigene resistance.When resistant lines JI 97 and JI 1089 were crossed with a susceptible line and leaves and stems of each F2 plant were inoculated, resistance phenotypes segregated independently demonstrating that leaf and stem resistance were controlled by different genes. In two experiments where the F2 progeny of the cross JI 97×JI 1089 were tested for stem and leaf resistance separately, both characters segregated in a ratio of 15 resistant:1 susceptible indicating that these two resistant lines contain two non-allelic genes for stem resistance (designated Rmp1 and Rmp2) and two for leaf resistance (designated Rmp3 and Rmp4). Evidence that the gene for leaf resistance in JI 1089 is located in linkage group 4 of Pisum sativum is presented. 相似文献
2.
Rupakula Aruna D. Manohar Rao L. J. Reddy Hari D. Upadhyaya Hari C. Sharma 《Euphytica》2005,145(3):247-257
The legume pod borer, Helicoverpa armigera, is one of the most devastating pests of pigeonpea. High levels of resistance to pod borer have been reported in the wild
relative of pigeonpea, Cajanus scarabaeoides. Trichomes (their type, orientation, density and length) and their exudates on pod wall surface play an important role in
the ovipositional behavior and host selection process of insect herbivores. They have been widely exploited as an insect defense
mechanism in number of crops. In the present investigation, inheritance of resistance to pod borer and different types of
trichomes (A, B, C and D) on the pod wall surface in the parents (C. cajan and C. scarabaeoides) and their F1, F2, BC1 (C. cajan × F1), and F3 generations has been studied. Trichomes of the wild parents (high density of the non-glandular trichomes C and D, and glandular
trichome B and low density of glandular trichome A) were dominant over the trichome features of C. cajan. A single dominant gene as indicated by the segregation patterns individually will govern each trait in the F2 and backcross generation. Segregation ratio of 3 (resistant): 1 (susceptible) for resistance to pod borer in the F2 generation under field conditions was corroborated with a ratio of 1:1 in the backcross generation, and the ratio of 1 non-segregating
(resistant): 2 segregating (3 resistant: 1 susceptible): 1 non-segregating (susceptible) in F3 generation. Similar results were obtained for pod borer resistance under no-choice conditions. Resistance to pod borer and
trichomes associated with it (low density of type A trichome and high density of type C) are governed individually by a dominant
allele of a single gene in C. scarabaeoides. Following backcrossing, these traits can be transferred from C. scarabaeoides into the cultivated background. 相似文献
3.
Downy mildew, incited by Peronospora parasitica (Pers.: Fr.) Fr., is a destructive disease of broccoli (Brassica oleraceaL., Italica Group). Resistant cultivars represent a desirable control method to provide a practical, environmentally benign,
and long-term means of limiting damage from this disease. Doubled-haploid (DH) lines developed by us exhibit a high level
of downy mildew resistance at the cotyledon stage. To determine the mode of inheritance for this resistance, a resistant DH
line was crossed to a susceptible DH line to make an F1, from which F2 and backcross (BC) populations were developed. All populations were evaluated for response to artificial inoculation with
P. parasitica at the cotyledon stage. All F1 plants (including reciprocals) were as resistant as the resistant parent, indicating no maternal effect for this trait. F2 populations segregated approximately 3resistant to 1 susceptible, BC populations using the resistant parent as the recurrent
parent contained all resistant plants, and the BC to the susceptible parent segregated 1 resistant to 1 susceptible. These
results indicate that resistance is controlled by a single dominant gene. This gene should be easily incorporated into F1 hybrids and used commercially to prevent downy mildew at the cotyledon stage.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
4.
Three segregating F2 populations were developed by self-pollinating 3 black rot resistant F1 plants, derived from across between black rot resistant parent line 11B-1-12 and the susceptible cauliflower cultivar ‘Snow
Ball’. Plants were wound inoculated using 4 isolates ofXanthomonas campestris pv. campestris (Xcc) race 4, and disease severity ratings of F2 plants from the three populations were scored. A total of 860 arbitrary oligonucleotide primers were used to amplify DNA
from black rot resistant and susceptible F2 plants and bulks. Eight RAPD markers amplified fragments associated with completely disease free plants following black rot
inoculation,which segregated in frequencies far lower than expected. Segregation of markers with black rot resistance indicates
that a single, dominant major gene controls black rot resistance in these plants. Stability of this black rot resistance gene
in populations derived from 11B-1-12 may complicate introgression into B. oleracea genotypes for hybrid production.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
5.
The occurrence of a new isolate from the G5 strain of Soybean mosaic virus (SMV), which broke the resistance of soybean cultivar FT-10, was first reported in Brazil in 1995. Cultivar Davis is an ancestor
of ‘FT-10’ and the likely source of resistance to the virus. Diallel crosses among resistant cultivars Epps (PI 96983), Ogden
and FT-10, and susceptible cultivar Hill were made to investigate the inheritance of SMV resistance in FT-10. The experiments
for genetic studies were performed undergreen house conditions. Plants of the F2 population and F3 families from each cross and the parents were inoculated with SMV G1 and G5 strains. Plants were classified as: symptom less
(R), susceptible with typical symptoms of mosaic (S), and systemic necrosis (N). Plants showing necrosis or no symptoms were
classified as resistant. Each F3 family was classified as resistant (homozygous),susceptible (homozygous), or segregating (heterozygous). The results of both
F2 and F3 were analyzed by Chi-square tests. The results suggested that FT-10 carries an allele at the Rsv
1 locus for resistance to SMV. However, the allele is different from those in Epps and Ogden. The symbol Rsv
1
d is a tentatively named for the newly detected allele in FT-10. This allele probably originated from Davis cultivar.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
6.
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
7.
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
8.
The objective of this study was to determine the mode of inheritance of field resistance to downy mildew (Peronospora parasitica (Pers. ex Fr.) Fr.) in broccoli (Brassica oleracea var.italica) at the adult plant stage. The F1, F2 and F3 progeny of resistant and susceptible plants of broccoli were tested in the field under natural infection, in central Portugal,
from August to December in two successive years. The plants were evaluated for resistance to downy mildew at maturity using
a five-class scale of increasing susceptibility to the disease, which took into account the number of infected leaves and
the size of the sporulating lesions. The F1 was completely resistant, the F2 segregated a clear 3 resistant: 1susceptible and the F3 confirmed the F2 segregation, which suggests a dominant character controlled by a single locus. This resistance has good potencial for direct
use in commercial broccoli breeding or for transfer to other Brassica vegetables.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
9.
R. Subramanya 《Euphytica》1982,31(2):461-464
Summary Progenies of a cross between pepper cultivar Delray Bell (Capsicum annuum L.) tolerant to pepper mottle virus (PeMoV) and P.I. 159236 (Capsicum chinense
Jacq.), resistant to PeMoV were evaluated in greenhouse experiments. The F1 generation was susceptible to PeMoV, whereas the backeross generations to both parents and the F2 segregated in a ratio of 1:1. This indicates that PeMoV resistance is controlled at the same locus in both parents or at two closely linked loci. Each parent is homozygous for one locus and the homozygous condition of either allele results in failure to support virus; in heterozygous condition as observed in the F1 generation, the effect of a single allele is insufficient even when one allele of each type is present, resulting in systemic infection.The abstract of this paper was presented at the IVth Eucarpia Capsicum meetings held in October at Wageningen, Netherlands.Florida Agricultural Experiment Stations Journal Series Paper No. 3175. 相似文献
10.
Summary Simulated segregating barley populations were screened for resistance to scald (Rhynchosporium secalis) in the field at commercial seeding rates. A reduction in infection on the susceptible component occurred with increasing proportions of resistant genotypes. Similar trends were seen in space planted experiments but the use of susceptible buffer rows counteracted the effect, enhanced the infection in susceptible plants and greatly improved discrimination between resistant and susceptible. These results have been applied to the routine testing of F2 populations in the barley breeding programme. 相似文献
11.
R. Amiri M. Moghaddam M. Mesbah S. Yaghoub Sadeghian M.R. Ghannadha K. Izadpanah 《Euphytica》2003,132(3):363-373
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
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.
Resistance to the southern root-knot nematode Meloidogyne incognita Chitwood would be an important attribute of lettuce Lactuca sativa L. cultivars adapted to both protected and field cultivation in tropical regions. `Grand Rapids' and a few other cultivars
are reported to be resistant to this nematode. In this paper, we studied the inheritance of the resistant reaction of `Grand
Rapids' (P2) in a cross with a standard nematode-susceptible cultivar Regma-71 (P1). F1(Regina-71 × Grand Rapids) and F2 seed were obtained, and inoculated along with the parental cultivars with different races of M. incognita to evaluate nematode resistance. Broad sense heritability estimates for the number of galls and of egg masses per root system,
gall size and gall index were generally in the order of 0.5 or higher. Class distributions of these variables over generations
P1, P2, F1 and F2 were in agreement with simulated theoretical distributions based on monogenic inheritance models. F3 families were obtained from randomly sampled F2 plants and tested for reaction to the nematode. The frequency ratio of homozygous resistant, segregating and homozygous susceptible
F3 families did not differ from the 1:2:1 ratio expected from monogenic inheritance. M. incognita resistance appears to be under control of a single gene locus. The Grand Rapids allele (for which the symbol Me is proposed) is responsible for the resistant reaction, and shows high (though incomplete) penetrance, variable expressivity
and predominantly additive gene action.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
14.
Russian wheat aphid (RWA), Diuraphis noxia (Kurdjumov), is a serious pest of small grains in many countries. A previous study screened 70 genotypes, collected from
different parts of Iran, for RWA resistance. Four crosses were made between two resistant lines (Shz.W-102 and Shz.W-104)
and two susceptible lines (Shz.W-101 and Shz.W-103). Parents, F1, F2, and BCF1 seedlings were screened for RWA resistance in the greenhouse by artificial infection. To determine allelism, the two resistant
lines were intercrossed and F1, and F2 seedlings were evaluated. Resistance in Shz.W-102 and Shz.W-104, when crossed with Shz.W-101, was controlled by one dominant
gene. However, resistance in Shz.W-102 and Shz.W-104, when crossed with Shz.W-103, was controlled by two dominant genes. Genes
in two resistant lines segregated independently of each other. A three-gene system was proposed to govern resistance in the
lines under study .
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
15.
Summary Three lentil genotypes resistant to Fusarium oxysporum f.sp. lentis viz. Pant L 234, JL 446 and LP 286 were crossed with two susceptible ones. The hybrid plants were all resistant in the eight crosses evaluated. Segregation pattern for wilt reaction in F2, BC(P1), BC(P2) and F3 generations in field and glasshouse conditions indicated that resistance to Fusarium wilt is under the control of two dominant duplicate genes in Pant L 234 and two independent dominant genes with complementary effects in JL 446 and LP 286. A third dominant gene complementary to the dominant genes in JL 446 and LP 286 is present in two susceptible lines. Allelic tests suggest the presence of five independently segregating genes for resistance. Duplicate dominant genes in Pant L 234 are non-allelic to two dominant genes with complementary effects in LP 286 and JL 446 and the third gene complementary to the two genes in JL 446 and LP 286 in susceptible lines JL 641 and L 9–12. Gene symbols among parental genotypes have been designated. 相似文献
16.
Summary Six chickpea lines resistant to Ascochyta rabiei (Pass.) Lab. were crossed to four susceptible cultivars. The hybrids were resistant in all the crosses except the crosses where resistant line BRG 8 was involved. Segregation pattern for diseases reaction in F2, BCP1, BCP2 and F3 generations in field and glasshouse conditions revealed that resistance to Ascochyta blight is under the control of a single dominant gene in EC 26446, PG 82-1, P 919, P 1252-1 and NEC 2451 while a recessive gene is responsible in BRG 8. Allelic tests indicated the presence of three independently segregating genes for resistance; one dominant gene in P 1215-1 and one in EC 26446 and PG 82-1, and a recessive one in BRG 8.Research paper No. 3600 相似文献
17.
Summary The genetics of partial resistance of lettuce to Myzus persicae was studied using F1 and F2 generations of two crosses between a susceptible and partially resistant accession (Norden x Batacer and Liba x Norden) and three crosses in which both parents were partially resistant (Batavia la Brillante x Batacer, Batacer x Liba and CGN4741 x Batacer). Partial resistance to M. persicae inherited quantitatively, without important dominance effects. Only in the cross Batacer x Liba were significant departures of the F1 and F2 from the midparent found, which were probably caused by epistatic effects. Reciprocal F1s had similar resistance levels, indicating the absence of cytoplasmic or other maternal effects. Estimates of broad-sense heritability ranged from 0.34 to 0.61. The results indicated that lines with an improved resistance level can be obtained from crosses between partially resistant accessions, preferably by line selection or the application of indirect marker aided selection.Abbreviations PR
partial resistance, partially resistant
- S
susceptibility, susceptible 相似文献
18.
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
19.
Juthaporn Khampila Kamol Lertrat Weerasak Saksirirat Jirawat Sanitchon Nooduan Muangsan Piyada Theerakulpisut 《Euphytica》2008,164(3):615-625
Exserohilum turcicum causes northern corn leaf blight (NCLB), an important disease occurring in maize producing areas throughout the world. Currently,
the development of cultivars resistant to E. turcicum seems to be the most efficient method to control NCLB damage. Marker-assisted selection (MAS) enables breeders to improve
selection efficiency. The objective of this work was to identify random amplified polymorphic DNA (RAPD) and sequence characterized
amplified region (SCAR) markers associated with NCLB resistance. Bulked segregant analysis (BSA) was used to search for RAPD
markers linked to NCLB resistance genes, using F2 segregating population obtained by crossing a susceptible inbred ‘209W’ line with a resistant inbred ‘241W’ line. Two hundred
and twenty-two decamer primers were screened to identify four RAPD markers: OPA07521, OPA16457, OPB09520, and OPE20536 linked to NCLB resistance phenotype. These markers were converted into dominant SCAR markers: SCA07496, SCA16420, SCB09464, and SCE20429, respectively. The RAPD and SCAR markers were developed successfully to identify NCLB resistant genotypes in segregating
progenies carrying NCLB resistant traits. Thus, the markers identified in this study should be applicable for MAS for the
NCLB resistance in waxy corn breeding programs. 相似文献
20.
Summary Cucumber (Cucumis sativus) lines resistant to angular leafspot caused by Pseudomonas lachrymans react to an infection by developing necrotic lesions that lack the chlorotic halo characteristic of the susceptible reaction. The inheritance of the non-halo lesion reaction was studied in all possible crosses between resistant lines MSU 9402 and Gy 14A, and susceptible cultivars Wisc. SMR 18 and National Pickling. Genetic analysis of the F1, F2, backcross and F3 populations revealed that the non-halo lesion type, associated with resistance, was controlled by a single recessive gene, pl. This character appears to be an important component of resistance to P. lachrymans. 相似文献