INHERITANCE OF RESISTANCE TO BLACK SHANK IN NICOTIANA TABACUM L.

1971 ◽  
Vol 13 (3) ◽  
pp. 422-428 ◽  
Author(s):  
G. B. Collins ◽  
Paul D. Legg ◽  
C. C. Litton ◽  
M. J. Kasperbauer

Resistance to race 0 of black shank (Phytophthora parasitica var. Nicotianae) derived from Nicotians longiflora Cav. and transferred to the burley tobacco breeding line L8 appears to be conditioned by a single dominant gene. However, on the basis of expected ratios for a single dominant gene, a deficiency of resistant progeny was observed in the F2 and backcross generations. Haploid plants extracted from F1 individuals heterozygous for black shank resistance substantiated the deficiency in the resistance class. The haploid segregation with reduced recovery of the resistant genotype rules out preferential pollination as the cause for the altered ratios. The mechanism responsible for impaired function of the gamete carrying the allele for resistance is not known.

1969 ◽  
Vol 11 (2) ◽  
pp. 382-388
Author(s):  
G. B. Collins ◽  
P. D. Legg

Cytological investigations of a burley tobacco (Nicotiana tabacum L.) breeding line designated as L-8 and carrying race 0 black shank resistance derived from a cross with N. longiflora Cav. revealed the regular occurrence of 24 bivalents at metaphase I of meiosis. Instability was apparent at the meiotic anaphase and tetrad stages and from observations of mitotic anaphase and metaphase figures. Pollen viability of L-8 as estimated by a staining technique was very similar to that obtained for a standard burley variety. Comparable cytological observations were extended to the F1 hybrids of L-8 with three burley varieties. The findings were similar for L-8 and the F1 hybrids. The occurrence of 24 bivalents in meiocytes of F1 hybrids provided strong evidence for incorporation of black shank resistance from N. longiflora into N. tabacum by segmental substitution rather than by alien addition of a longiflora chromosome as previously reported.


2009 ◽  
Vol 99 (9) ◽  
pp. 1085-1089 ◽  
Author(s):  
C. R. Brown ◽  
H. Mojtahedi ◽  
L.-H. Zhang ◽  
E. Riga

Resistance to Meloidogyne chitwoodi was introgressed from Solanum bulbocastanum into the cultivated gene pool of potato. A single dominant gene is responsible for resistance to race 1 reproduction on the root system. An additional form of resistance was discovered in certain advanced backcross clones. A BC5 clone, PA99N82-4, resisted invasion of tubers by available nematode juveniles whether supplied by weeds or challenged by several root resistance-breaking pathotypes. This tuber resistance is inherited as a single dominant gene and is linked to RMc1(blb). Because this gene has been mapped to chromosome 11, tuber resistance genetic factors are inferred to be on the same chromosome in coupling phase. Among 153 progeny derived from crosses with PA99N82-4, 42 recombinants, comprising both resistant root/susceptible tuber and susceptible root/resistant tubers, were found while other progeny were doubly resistant (like PA99N82-4) or doubly susceptible. Therefore, the existence of two linked genetic factors controlling independently expressed traits is confirmed. The combination of the two phenotypes is likely to be a sufficient level of resistance to avoid tuber damage from circumstances that provide exogenous juveniles proximal to the tubers in the soil. These factors are weed hosts of M. chitwoodi host races and pathotypes of M. chitwoodi that overcome RMc1(blb). Under field conditions, where a resistance-breaking pathotype of M. chitwoodi was present, tuber-resistant PA99N82-4 breeding line produced tubers which were commercially acceptable and not culled. A related breeding line, root resistant but tuber susceptible, and Russet Burbank were severely tuber damaged and commercially unacceptable.


1980 ◽  
Vol 22 (1) ◽  
pp. 27-33 ◽  
Author(s):  
D. E. Harder ◽  
R. I. H. McKenzie ◽  
J. W. Martens

The inheritance of resistance to oat crown rust was studied in three accessions of Avena sterilis L. Accession CAV 4274 originated from Morocco, CAV 4540 from Algeria, and CAV 3695 from Tunisia. Seedling rust tests on F2 backcross families indicated the presence of two dominant genes for crown rust resistance in CAV 4274. One of these, a gene conditioning resistance to most races tested, was linked or allelic to gene Pc-38, and was designated gene Pc-62. The second gene conferred resistance only to one of the six races studied, and was not tested further. In CAV 4540, a single dominant gene, Pc-63 was possibly allelic with Pc-62 and linked or allelic to Pc-38. Genes Pc-62 and 63 are generally similar to Pc-38 in their resistance spectrum, but these three genes are differentiated by races CR 102, CR 103, and CR 107. A single dominant gene in CAV 3695 appeared to be Pc-50.


Plant Disease ◽  
2002 ◽  
Vol 86 (10) ◽  
pp. 1080-1084 ◽  
Author(s):  
E. S. Johnson ◽  
M. F. Wolff ◽  
E. A. Wernsman ◽  
W. R. Atchley ◽  
H. D. Shew

Flue-cured tobacco (Nicotiana tabacum) cultivar Coker 371-Gold (C 371-G) possesses a dominant gene, Ph, that confers high resistance to black shank disease, caused by race 0 of the soil-borne pathogen Phytophthora parasitica var. nicotianae. The origin of this gene is unknown. Breeding lines homozygous for the Ph gene were hybridized with NC 1071 and L8, flue-cured and burley genotypes known to possess qualitative resistance genes from Nicotiana plumbaginifolia and N. longiflora, respectively. The F1 hybrids were out-crossed to susceptible testers and the progenies evaluated in field black shank nurseries and in greenhouse disease tests with P. parasitica var. nicotianae race 0. Results showed that Ph was allelic to Php from N. plumbaginifolia in NC 1071. Testcross populations of hybrids between burley lines homozygous for Ph and L8, possessing Phl from N. longiflora, showed that Ph and Phl integrated into the same tobacco chromosome during interspecific transfer. Nevertheless, the two loci were estimated to be 3 cM apart. Random amplified polymorphic DNA (RAPD) analyses of the testcross progenies confirmed that recombination between the two loci was occurring. Forty-eight RAPD markers linked to Ph in doubled haploid lines were used in cluster analyses with multiple accessions of N. longiflora and N. plumbaginifolia, breeding lines L8, NC 1071, and DH92-2770-40, and cultivars K 326, Hicks, and C 371-G. A cladogram or region tree confirmed the data obtained from field and greenhouse trials, that Ph, transferred from C 371-G to DH92-2770-40, and Php in NC 1071 were allelic and originated from N. plumbaginifolia.


1962 ◽  
Vol 42 (1) ◽  
pp. 69-77 ◽  
Author(s):  
E. N. Larter ◽  
H. Enns

Four barley varieties, each immune to a Valki-attacking culture of loose smut (designated as race 2), were studied with respect to the inheritance of their resistance. Jet (C.I. 967) and Nigrinudum (C.I. 2222) were each found to possess two independent dominant genes determining resistance. Steudelli (C.I. 2266) proved to be immune to race 2 through the action of a single dominant gene, while resistance of Hillsa (C.I. 1604) was found to be conditioned by two complementary dominant genes. The absence of susceptible F3 families in crosses between Jet, Nigrinudum, and Steudelli indicated that these three varieties have in common a gene or genes for resistance to the race of smut used. The two complementary genes for resistance in Hillsa proved to be distinct from those of the other three varieties under study.The use of genetic analyses of disease resistance based upon classification of F3 families of the backcross to the resistant source is described and the merits of such a method are discussed.


Plants ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1652
Author(s):  
Cheng-Sheng Zhang ◽  
Yanfen Zheng ◽  
Lijuan Peng ◽  
Jianmin Cao

The composition and allelopathy to Phytophthora nicotianae (the causal agent of tobacco black shank disease) of root exudates from a resistant tobacco (Nicotiana tabacum L.) cultivar Gexin 3, a susceptible cultivar Xiaohuangjin 1025 and their reciprocal grafts were investigated. Grafting with disease-resistant rootstock could improve resistance to black shank; this is closely related to the allelopathy of root exudates. The root exudates from the resistant cultivar inhibited the growth of P. nicotianae, while those from the susceptible cultivar promoted the growth; the grafting varieties had intermediate properties. The root exudate composition differed among cultivars. Gexin 3 was rich in esters and fatty acids, while Xiaohuangjin 1025 contained more hydrocarbons and phenolic acids. The composition of root exudates of grafted cultivars as well as their allelopathy to P. nicotianae were altered, and tended to be close to the composition of cultivar used as rootstock. Eugenol, 4-tert-butylphenol, mono (2-ethylhexyl) phthalate, 4-hydroxybenzoic acid, 2,6-di-tert-butylphenol, dipropyl phthalate, and methyl myristate were identified as the main compounds contributing to inhibitory properties of root exudates. Sorbitol was suggested to play a role in disease induction. Overall, rootstock–scion interaction affected the composition of tobacco root exudates, which may be attributed to the different disease resistance among grafted plants, rootstock and scion.


2016 ◽  
Vol 43 (6) ◽  
pp. 534 ◽  
Author(s):  
Roxana Portieles ◽  
Eduardo Canales ◽  
Osmani Chacon ◽  
Yussuan Silva ◽  
Ingrid Hernández ◽  
...  

Many host genes induced during compatible plant–pathogen interactions constitute targets of pathogen virulence factors that act to suppress host defenses. In order to identify Nicotiana tabacum L. genes for pathogen-induced proteins involved in susceptibility to the oomycete Phytophthora parasitica var. nicotianae, we used SuperSAGE technology combined with next-generation sequencing to identify transcripts that were differentially upregulated during a compatible interaction. We identified a pathogen-induced gene (NtPIP) that was rapidly induced only during the compatible interaction. Virus-induced gene silencing of NtPIP reduced the susceptibility of N. tabacum to P. parasitica var. nicotianae. Additionally, transient expression of NtPIP in the resistant species Nicotiana megalosiphon Van Heurck & Mull. Arg. compromised the resistance to P. parasitica var. nicotianae. This pathogen-induced protein is therefore a positive regulator of the susceptibility response against an oomycete pathogen in tobacco.


1975 ◽  
Vol 55 (1) ◽  
pp. 303-308
Author(s):  
V. KOZUMPLIK ◽  
P. P. LUKOSEVICIUS

Response of cigar tobacco (Nicotiana tabacum L.) in morphological, agronomic and chemical characteristics to date of planting and planting distance was studied during 1971–73. A cultivar and a breeding line of cigar tobacco were transplanted outdoors on 26 May, 9 (or 12) June and 23 June. The tobacco was spaced 36, 41 and 46 cm in rows that were 97 cm apart. The best results were obtained when cigar tobacco was transplanted not later than 9 June, and the plants were spaced 41 cm in the rows that were 97 cm apart. The highest number of leaves per plant, cured-leaf yield, percentage of nicotine and total alkaloids were obtained from the tobacco transplanted on the first or second date in 3 yr. In 2 yr, the later tobacco had the tallest plants, the largest leaves, the highest percent filler leaf, grade and crop index. Earlier-transplanted tobacco was harvested earlier, although the period to flower decreased with later date of planting. On the average, the tobacco spaced 41 cm was taller and had a shorter period to flower, and higher yield and crop index than that spaced 36 cm or 46 cm. Grade index, percent filler leaf, nicotine and total alkaloids were affected significantly by the distance in 1 yr only.


Sign in / Sign up

Export Citation Format

Share Document