scholarly journals A Detached Leaf Technique for Studying Race-specific Resistance to Cladosporium caryigenum in Pecan

2002 ◽  
Vol 127 (5) ◽  
pp. 781-785 ◽  
Author(s):  
Patrick J. Conner
Keyword(s):  
High Frequency ◽  
Specific Resistance ◽  
Fungal Growth ◽  
Carya Illinoinensis ◽  
Detached Leaf ◽  
Pecan Scab ◽  
Detached Leaves ◽  
Cladosporium Caryigenum ◽  
Cape Fear ◽  
High Degree

A detached leaf screening technique was developed for studying specific interactions between pecan [Carya illinoinensis (Wangenh.) C. Koch] cultivars and isolates of the pecan scab fungus, Cladosporium caryigenum. Monoconidial isolates were obtained from leaf scab lesions on `Wichita', `Desirable', `Cape Fear', and `Elliot'. Each isolate was then inoculated onto detached leaves of each of the four cultivars and fungal growth was observed under the microscope after eight days. `Wichita', `Desirable', and `Cape Fear' isolates produced subcuticular hyphae at a much higher frequency when inoculated back onto the cultivar from which they were isolated in comparison to the other cultivars. The `Elliot' isolate was able to produce a high frequency of subcuticular hyphae when inoculated onto `Elliot' and `Cape Fear', but not when inoculated onto `Desirable' and `Wichita'. Field inoculations conducted with the `Wichita' and `Desirable' isolates validated the detached leaf protocol. The results obtained indicate that pecan scab is composed of multiple races with a high degree of specificity for host cultivars. A rapid whole-leaf staining system is presented which appears to have wide applicability to assessing fungal growth in leaves.

scholarly journals Detached leaf in vitro model for masked mycotoxin biosynthesis and subsequent analysis of unknown conjugates

2014 ◽  
Vol 7 (3) ◽  
pp. 305-312 ◽  
Author(s):  
M. De Boevre ◽  
A. Vanheule ◽  
K. Audenaert ◽  
B. Bekaert ◽  
J. Diana Di Mavungu ◽  
...  
Keyword(s):  
In Vitro Model ◽  
High Resolution Mass Spectrometry ◽  
Reference Standard ◽  
Detached Leaf ◽  
Detached Leaves ◽  
Food And Feed ◽  
Vitro Model ◽  
Mycotoxin Biosynthesis ◽  
Derivatives Of

The manuscript details the development of an in vitro model plant system using detached leaves because there is a need for biosynthetic methods for the production and isolation of masked mycotoxins. This detached leaf in vitro model was firstly applied to deoxynivalenol with satisfying results. The biosynthesis of deoxynivalenol-3-glucoside was confirmed using its respective commercially available reference standard. Secondly, the detached leaf in vitro model was applied to T-2 toxin. Mono- and tri-glucoside derivatives of T-2 toxin and HT-2 toxin, T-2-(3)-glucoside, T-2-(3)-triglucoside and HT-2-(3)-glucoside were identified and characterised using Orbitrap high-resolution mass spectrometry. This is the first report on a triglucoside of T-2 toxin. The discovery of new masked forms implies the importance of the development of analytical methods for their detection, the constitution of toxicity studies, and proving the relevance of their presence in the food and feed chain.

Assessing resistance to spring black stem and leaf spot of alfalfa caused by Phoma spp.

2004 ◽  
Vol 84 (1) ◽  
pp. 311-317 ◽  
Author(s):  
H. Wang ◽  
S. F. Hwang ◽  
K. F. Chang ◽  
B. D. Gossen ◽  
G. D. Turnbull ◽  
...  
Keyword(s):  
Medicago Sativa ◽  
Leaf Spot ◽  
Similar Pattern ◽  
Disease Incidence ◽  
Field Trials ◽  
Disease Reaction ◽  
Detached Leaf ◽  
Controlled Conditions ◽  
Detached Leaves ◽  
Phoma Sclerotioides

The disease reaction of alfalfa (Medicago sativa) cultivars to spring black stem was evaluated in field trials and greenhouse experiments. In field trials, differences in cultivar reaction to leaf spot (predominantly spring black stem) were observed in 9 of 16 station years. The reaction of certain cultivars was consistent across most trials, but other cultivars were quite variable. Under controlled conditions, one isolate each of Phoma sclerotioides and P. exigua produced symptoms on alfalfa leaves that were similar to those caused by P. medicaginis. These results indicate that P. medicaginis is not the only pathogen responsible for symptoms of spring black stem on alfalfa in the prairie region. In a detached-leaf study, one isolate each of P. medicaginis, P. sclerotioides and P. exigua produced leaf lesions on all 18 alfalfa cultivars assessed. Disease incidence in Absolute, Algonquin, Pickseed 3006 and Anik (M. sativa subsp. falcata) was lower than in 630 and AC Blue J. Inoculation of eight selected cultivars using a range of spore concentrations under controlled conditions showed a similar pattern; all three isolates produced leaf lesions on all eight cultivars. Ino culation with conidial suspensions of P. medicaginis resulted in a lower disease incidence on Absolute than on Beaver. Key words: Medicago sativa, Medicago sativa subsp. falcata, Phoma medicaginis, P. sclerotioides, P. exigua, detached leaves.

Regenerative studies on the detached leaves of Echeveria elegans. Patterns of regeneration of leaves in sterile culture

1971 ◽  
Vol 49 (11) ◽  
pp. 2015-2021 ◽  
Author(s):  
M. V. S. Raju ◽  
Henry E. Mann
Keyword(s):  
Agar Medium ◽  
Shoot Formation ◽  
Proximal Region ◽  
Leaf Base ◽  
Regeneration Potential ◽  
Inverted Position ◽  
Sterile Culture ◽  
Regeneration Pattern ◽  
Detached Leaf ◽  
Detached Leaves

Entire detached leaves (L30 and older) and leaf-halves of Echeveria elegans Bgr. were cultured aseptically on an agar medium to study their regenerative capacity. The entire leaves with their bases intact produced shoots and roots regardless of whether they were placed erect, inverted, or flat on the medium. Similar leaves with their bases severed and placed erect produced roots from their cut ends. The proximal leaf-halves showed a regeneration pattern similar to the entire leaves depending on, of course, whether the leaf bases were cut or not. The regeneration in the distal halves was identical to the proximal halves whose bases had been removed. In the inverted position, a few distal halves and proximal halves with their bases removed produced shoots and roots. In all leaf types, inverted, erect, or flat, the regeneration occurred at the proximal end and in some exceptional cases, roots were formed at the distal cut end too. In general, the regeneration potential appeared to be much greater in the proximal parts than in the distal parts of detached leaves and the anatomy in the former was more favorable for regeneration than in the latter. Cutting the leaf base altered the regeneration pattern in the detached leaf but it did not have any effect on the capacity for regeneration to produce differentiated organs. The leaf fragments showed strict polarity in shoot formation which occurred only in the proximal region. The roots, on the other hand, appeared at proximal and distal ends.

scholarly journals No Adverse Effect of Early Season Fungicide and Zinc Sprays on Leaf Area, Fruit Set, and Nut Quality of Pecan

HortScience ◽  
1996 ◽  
Vol 31 (5) ◽  
pp. 808-810
Author(s):  
Charles C. Reilly ◽  
Bruce W. Wood
Keyword(s):  
Adverse Effect ◽  
Leaf Area ◽  
Zinc Sulfate ◽  
Fruit Set ◽  
No Reduction ◽  
Leaf Age ◽  
Carya Illinoinensis ◽  
Early Season ◽  
Pecan Scab

Propiconazole, a fungicide, suppressed leaf area of a wide variety of young pecan [Carya illinoinensis (Wangenh.) K. Koch] seedling genotypes but did not reduce leaf area of orchard trees. Leaf area declined linearly as dosage increased from 0.16 to 1.25 mL·L–1. Suppression of leaf area by propiconazole was inversely proportional to leaf age. No reduction of leaf area was detected in orchards where `Cheyenne', `Desirable', and `Pawnee' were treated with three applications (14-day intervals) of fungicide (either propiconazole, fentin hydroxide, or fenbuconazole) from budbreak to early May. Spring application of the three fungicides alone or in combination with zinc sulfate did not influence fruit set. Control of pecan scab [Cladosporium caryigenum (Ell. et Lang) Gottwald] was achieved with either fentin hydroxide or fenbuconazole for the full season, or with early season use of dodine, then propiconazole, and then followed by fentin hydroxide for late-season disease control. Fungicide treatments had no effect on nut weight. These data indicate that fungicides applied to pecan during pollination at commercially recommended dosages and intervals, with or without zinc sulfate, do not adversely influence leaf area or fruit set of orchard trees. Chemical names used: n-dodecylguanidine acetate (dodine); triphenyltin hydroxide (fentin hydroxide); 1-[[2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl] methyl]-1H-1,2,4-triazole (propiconazole); α-[2-(4-chlorophenyl)ethyl]-α-phenyl-1H-1,2,4-triazole-1-propanenitrile (fenbuconazole).

scholarly journals Pathogenic Variation of Cladosporium caryigenum Isolates and Corresponding Differential Resistance in Pecan

HortScience ◽  
2004 ◽  
Vol 39 (3) ◽  
pp. 553-557 ◽  
Author(s):  
Patrick J. Conner ◽  
Katherine L. Stevenson
Keyword(s):  
Plant Cell Wall ◽  
Differential Resistance ◽  
Carya Illinoinensis ◽  
Causal Organism ◽  
Breeding Programs ◽  
Large Pool ◽  
Pathogenic Variation ◽  
Virulence Pattern ◽  
Cladosporium Caryigenum ◽  
Selection Of

To facilitate the breeding of scab-resistant pecan [Carya illinoinensis (Wangenh.) C. Koch] cultivars, more information is needed about the pathogenic variation of the causal organism, Cladosporium caryigenum (Ell. et Lang.) Gottwald (1982). This study examined the virulence patterns resulting from the field inoculations of 19 pecan cultivars with 12 monoconidial isolates from 8 pecan cultivars at 7 locations. The virulence pattern was different for each of the fungal isolates. Each isolate was virulent on some cultivars and avirulent on others. Most isolates were most virulent on the cultivar of their origin and one or a few other cultivars. Several cultivars were resistant to most of the tested isolates. The results indicate a large pool of differential and ephemeral resistance to scab resides in the pecan germplasm. Microscopic examination of developing lesions suggests that resistance is mediated by the speed of plant cell wall modifications that limit the growth of subcuticular hyphae. This information will be useful in the selection of cultivars with functionally different resistance genes for use in designing cultivar mixtures or in breeding programs.

scholarly journals Reaction of wheat cultivars and differential lines to Puccinia triticina races in detached leaves

2014 ◽  
Vol 40 (4) ◽  
pp. 353-357 ◽  
Author(s):  
Camila Turra ◽  
Erlei M. Reis ◽  
Amarilis L. Barcellos
Keyword(s):  
Puccinia Triticina ◽  
Petri Dish ◽  
Wheat Cultivars ◽  
Wheat Leaf Rust ◽  
Detached Leaf ◽  
Wheat Leaf ◽  
Detached Leaves ◽  
Wheat Leaves

The method of preserving detached wheat leaves in Petri dish was used for the inoculation and development of the fungus Puccinia triticina, the causal agent of wheat leaf rust. The reaction of 26 wheat cultivars was compared by using seedlings cultivated in pots (in vivo) and detached leaves (in vitro) inoculated with four physiological races of the pathogen. After inoculation, the material was kept in a growth chamber for 15 days. The reaction was evaluated on the 15th day after inoculation. Results for each race in the evaluated genotypes confirmed the efficiency of the detached leaf method in assessing the reaction of wheat cultivars.

scholarly journals Phytonutrients and Metabolism Changes in Topped Radish Root and Its Detached Leaves during 1 °C Cold Postharvest Storage

Horticulturae ◽  
2021 ◽  
Vol 8 (1) ◽  
pp. 42
Author(s):  
Mengpei Liu ◽  
Hye-Young Seo ◽  
Sunggi Min ◽  
Kang-Mo Ku
Keyword(s):  
Cold Storage ◽  
Plant Hormones ◽  
Root Tissue ◽  
Detached Leaf ◽  
Radish Root ◽  
Significant Difference ◽  
Detached Leaves ◽  
Storage Atmosphere ◽  
The Difference ◽  
Atmosphere Environment

Glucosinolates, lipid-soluble vitamins E and K contents, primary metabolites and plant hormones were analyzed from topped radish root and detached leaf during storage at 1 °C. The topped root was analyzed at 0, 5, 15, 30, and 90 days after storage while the detached leaf was analyzed at 0, 5, 15, 30, and 45 days in an airtight storage atmosphere environment. The results showed that aliphatic glucosinolates were gradually decreased in leaf but not in root. There was a highly significant correlation between tryptophan and 4-methoxyindoleglucobrassicin in both tissues (r = 0.922, n = 10). There was no significant difference in vitamins E and K in leaf and root during storage. Plant hormones partially explained the significantly changed metabolites by tissue and time, which were identified during cold storage. Phenylalanine, lysine, tryptophan, and myo-inositol were the most important biomarkers that explained the difference in leaf and root tissue during cold storage. The most different metabolism between leaf and root tissue was starch and sucrose metabolism. Therefore, different postharvest technology or regimes should be applied to these tissues.

scholarly journals Profitability of Mechanical Fruit Thinning of ‘Sumner’ and ‘Cape Fear’ Pecan

2009 ◽  
Vol 19 (3) ◽  
pp. 518-520
Author(s):  
M. Lenny Wells ◽  
D. Scott Carlson ◽  
R. Philip Edwards
Keyword(s):  
Carya Illinoinensis ◽  
Average Value ◽  
Fruit Thinning ◽  
Light Production ◽  
High Production ◽  
Mechanical Thinning ◽  
Cape Fear ◽  
Premature Germination ◽  
Profit Potential

The effects of mechanical fruit thinning on pecan [Carya illinoinensis (Wangenh.) K. Koch] yield, nut quality, and profitability were assessed using ‘Sumner’ and ‘Cape Fear’ pecan trees cultivated in a commercial orchard. The moderate to light production year (OFF year) return crop and return crop value of ‘Cape Fear’ and ‘Sumner’ was increased by mechanical thinning in the year of high production (ON year). This enhanced the 2-year total value and 2-year average value of both cultivars. Increased profitability of these cultivars with mechanical fruit thinning results primarily from higher yields and prices in the OFF year of production, which offset any loss in yield and/or crop value generated by fruit thinning in the ON year. Premature germination of ‘Cape Fear’ pecans was reduced from 34% to 4% with mechanical fruit thinning. Mechanical fruit thinning appears to be a highly valuable practice, leading to increased profit potential for ‘Cape Fear’ and ‘Sumner’ pecan.

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