INHERITANCE OF RESISTANCE TO FRUIT FLY IN WATERMELON

1978 ◽  
Vol 20 (1) ◽  
pp. 31-34 ◽  
Author(s):  
R. C. Khandelwal ◽  
Prem Nath

Inheritance of resistance to the fruit fly Dacus cucurbitae Coq., was studied in intervarietal crosses of watermelon Citrullus lanatus (Thunb.) Mansf. Two sources of resistance J 18-1 and J 56-1 were used. The resistance of watermelon to the fruit fly was controlled by a single dominant gene. The symbol Fwr has been proposed to denote the resistant gene.

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 534b-534
Author(s):  
James D. McCreight

Yellowing of melon (Cucumis melo L.) incited by lettuce infectious yellows virus (LIYV) reduces yield and fruit quality of infected plants. LIYV is transmitted only by the sweetpotato whitefly (Bemisia tabaci Genn.). Two naturally infected field tests indicated several potential sources of resistance to LIYV. PI 124112 and `Snake Melon' had mild symptoms in both field tests whereas PI 313970 was asymptomatic in the test in which it was included. In greenhouse tests using controlled inoculation, PI 313970 was asymptomatic, had negative ELISA assays for LIYV, and was negative for LIYV in serial transfers to Chenopodium. `Top Mark' and `PMR 5' were symptomatic, had positive ELISA assays for LIYV, and were positive for LIYV in serial transfers to Chenopodium in these greenhouse tests. Limited data indicate that resistance in PI 313970 is conditioned by a single, dominant gene.


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.


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.


HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 811C-811
Author(s):  
Nihat Guner* ◽  
Zvezdana Pesic-VanEsbroeck ◽  
Todd Wehner

Sources of resistance to the watermelon strain of papaya ringspot virus (PRSV-W) have been identified within the watermelon (Citrullus lanatus) germplasm collection. Inheritance of resistance to papaya ringspot virus-watermelon strain was studied in three C. lanatus var. citroides accessions: PI 244017, PI 244019, and PI 485583. The susceptible parent lines `Allsweet', `Calhoun Gray', and `New Hampshire Midget' were crossed with resistant accessions to develop F1, F2, and BC1 generations for six families. A single recessive gene was found to control resistance to PRSV-W. The gene symbol `prv' is proposed for PRSV-W resistance in watermelon. Additional work is needed to determine whether the genes in PI 244017, PI 244019, and PI 485583 are allelic for resistance to PRSV-W.


HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1109A-1109
Author(s):  
James D. McCreight

Lettuce aphid (Nasonovia ribisnigri Mosley) is a recent insect pest to lettuce (Lactuca sativa L.) production in the United States. The single dominant gene, Nr, conditions resistance to the lettuce aphid in Lactuca virosa accession IVT280 from The Netherlands and is available in a limited number of commercial lettuce cultivars. New and genetically unique sources of resistance are sought to broaden the genetic base for resistance to the lettuce aphid. About 1200 lettuce PI lines were evaluated for resistance to lettuce aphid in greenhouse tests using a strain of lettuce aphid obtained from commercial lettuce in Salinas Valley, Calif. In 2002, plants were individually infested with five 24-hour nymphs per plant (controlled protocol), and the numbers of aphids per plant were counted 10–14 days post-infestation (dpi). Beginning in 2003, plants were mass-infested (mass protocol) with nymphs and alates of various ages and numbers. Using the mass protocol, the number of aphids per plant 10–14 dpi were estimated and categorized using a 1–5 scale where 1 = 0 aphids per plant, 2 = 1–10 aphids per plant, 3 = 11–20 aphids per plant, 4 = 21–30 aphids per plant, and 5 = >30 aphids per plant. `Salinas' and `Barcelona' were included as susceptible and resistant controls, respectively. Most of the accessions were susceptible. A few accessions had a few plants with very low numbers of aphids after repeated infestation, but their progeny were susceptible. Two accessions were highly resistant: PI 491093, a Lactuca serriola accession from Turkey, and PI 274378, a L. virosa accession from France. Inheritance of resistance in these two accessions and their allelism to Nr remains to be determined.


2000 ◽  
Vol 125 (5) ◽  
pp. 615-618
Author(s):  
Richard L. Fery ◽  
Judy A. Thies

Greenhouse experiments determined the inheritance of resistance to the peanut root-knot nematode [Meloidogyne arenaria (Neal) Chitwood race 1] in Capsicum chinense Jacq. germplasm lines PA-353 and PA-426. Evaluation of parental, F1, F2, and backcross populations of the crosses PA-353 × PA-350 and PA-426 × PA-350 (PA-350 is a susceptible cultigen) indicated that resistance in both C. chinense germplasm lines was conditioned by a single dominant gene. Evaluation of the F1 × resistant parent backcross populations in the cytoplasm of their respective resistant and susceptible parents indicated that the cytoplasm of the resistant parent is not needed for full expression of resistance. Allelism tests indicated that the dominant resistance gene in both PA-353 and PA-426 is allelic to a resistance gene in C. annuum L. `Carolina Cayenne'. However, these allelism tests did not demonstrate conclusively that the M. arenaria race 1 resistance gene in C. chinense is the N gene that conditions resistance to the southern root-knot nematode [Meloidogyne incognita (Kofoid & White) Chitwood] in C. annuum. The ease and reliability of evaluating plants for resistance to root-knot nematodes and the availability of simply inherited sources of resistance makes breeding for peanut root-knot nematode resistance a viable objective in C. chinense breeding programs.


1969 ◽  
Vol 84 (1-2) ◽  
pp. 47-52
Author(s):  
Catherine Pardey ◽  
Federico Cuevas-Pérez ◽  
César P. Martínez ◽  
Alberto Pantoja

The inheritance of resistance to mechanical damage in rice caused by sogata, Tagosodes orizicolus (Muir), was studied in cultivars with this resistance. Evaluation of F1 and F3 generations suggests that resistance to mechanical damage is controlled by a single dominant gene (A). This gene, present in cultivars Makalioka and Mudgo, is homozygous. The gene confers resistance, but its expression is modified by another gene (B). The action of the modifier gene is dependent on the genotype and the exposure to insect attack. For Mudgo, the modifier gene is in the homozygous form (bb), which accelerates the expression of the susceptible phenotype. In Makalioka, the dominant homozygous form (BB) retards the expression of susceptibility.


HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1122f-1122
Author(s):  
Z. H. Guo ◽  
M. H. Dickson ◽  
J. E. Hunter

Resistance to Black rot was studied in B. oleracea, B. campestris and B. napus, using three different inoculation procedures. The results indicated that hydathode inoculation without wounding and the wound suspension technique were useful for differentiating levels of resistance found in B. oleracea and B. campestris, but not in B. napus. Only the wound colony method allowed differentiation between high and moderate resistance in B napus. B. napus, PI 199947 and PI 199949, exhibited the highest resistance found in cultivated Brassica species. In B. campestris, two chinese cabbage accessions showed quantitative inheritance for moderate levels of resistance. In B. napus, the high level of reistance was conferred by one dominant gene, to which the symbol Br was assigned, whereas the moderate resistance was due to one recessive gene bm.


HortScience ◽  
1991 ◽  
Vol 26 (2) ◽  
pp. 194-196 ◽  
Author(s):  
Sohedjie Ouattara ◽  
Oyette L. Chambliss

Reciprocal crosses were made between `White Acre-BVR', resistant to blackeye cowpea mosaic virus (BICMV), and the susceptible `California Blackeye No. 5' cowpea [Vigna unguiculata (L.) Walp.]. Seedlings from `California Blackeye No. 5', `White Acre-BVR', F1, F2, and backcrosses were mechanically inoculated with BICMV, and evaluated 4 weeks later for symptom expression in the greenhouse. Plants were assayed by enzyme-linked immunosorbent assay. The resistance observed in the F1 and progeny from the backcross to the resistant parent indicated that resistance to BICMV in `White Acre-BVR' was dominant. Furthermore, a 1 resistant: 1 susceptible segregation of progeny from the backcross to the susceptible parent and a 3 resistant: 1 susceptible segregation of the F2 progenies suggested that the resistance to BICMV in `White Acre-BVR' was conferred by a single dominant gene.


HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 506b-506
Author(s):  
Glare J. Coyne ◽  
Shawn A. Mehlenbacher

Eastern filbert blight (EFB) (Anisogramma anomala) is a serious disease of the European hazelnut (Coryls avellana). A single dominant gene for immunity to EFB from C. avellana `Gasaway' is being combined with good nut and kernel traits using a modified backcross approach. Additional sources of resistance would be highly desirable. Clones and seedlings of six other species (C. columa, C. comuta, C. heterophylla, C. sieboldiana, C. amencana, and C. jaquemontii] and a few interspecific hybrid selections were screened in the greenhouse to identify new sources of resistance. C. jacquemontii seedlings and C. columa clones were highly susceptible. C. comuta, C. hetemphylla, and C. sieboldiana clones were resistant, as were 86% of the C. americana seedlings tested. Five C. americana × C. avellana hybrids from New York were resistant under field conditions. One of four C. comuta × C. avellana and two of three C. hetemphylla × C. avellana hybrids were resistant.


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