Evaluation of an alternative small stem assay for blight resistance in American, Chinese, and hybrid chestnuts (Castanea spp.)

Plant Disease ◽  
2020 ◽  
Author(s):  
Martin Cipollini ◽  
John Patten Moss ◽  
William Walker ◽  
Natalie Bailey ◽  
Cooper Foster ◽  
...  
Keyword(s):  
Root Rot ◽  
Growing Season ◽  
Cryphonectria Parasitica ◽  
Castanea Dentata ◽  
Blight Resistance ◽  
Post Inoculation ◽  
Colored Zone ◽  
Clear Differentiation ◽  
One Year ◽  
Lower Stem

We tested an alternative small stem assay (SSA) for blight resistance in chestnuts (Castanea spp.). Whereas standard SSAs are done by inoculating small incisions in stems, we cut off stems (4 to 5 mm diameter), inoculated the cut ends with disks of Cryphonectria parasitica inoculum, and covered them with plastic sleeves. This method was designed to be relatively simple to implement, to consistently induce cankering, and to better enable seedlings to recover by developing shoots from the lower stem (standard SSAs delay removal of blighted stems until late in the growing season, if at all). We conducted six experiments with seedlings and orchard trees of Castanea dentata (susceptible), C. mollissima (resistant), and hybrids expected to vary in resistance. Experiments with seedlings and two of the three orchard experiments showed clear differentiation between susceptible and resistant types, especially after 90 days post-inoculation and when the orange-colored zone of the canker was measured. One orchard experiment failed to give clear results, but was ended earlier (60 days) than the other experiments. We observed only two failed inoculations out of over 200 performed. Comparisons with other studies suggest that this SSA method performs at least as well as the standard SSA method in distinguishing resistant and susceptible types, at least in seedlings. Survivorship after one year for seedlings inoculated in 2018 ranged from 70% for C. dentata to 100% for C. mollissima, and in 2019 ranged from 40% in F1s to 100% for C. mollissima. Deaths of seedlings following SSAs were mostly unrelated to the inoculations (e.g., root rot).

scholarly journals Phytopythium vexans Associated with Apple and Pear Decline in the Saïss Plain of Morocco

2021 ◽  
Vol 9 (9) ◽  
pp. 1916
Author(s):  
Salma Jabiri ◽  
Chaimaa Bahra ◽  
Dustin MacLean ◽  
Nabil Radouane ◽  
Essaid Ait Barka ◽  
...  
Keyword(s):  
Root Rot ◽  
Clay Soil ◽  
Post Inoculation ◽  
Pathogenicity Test ◽  
Apple Rootstock ◽  
Apple Rootstocks ◽  
Decline Disease ◽  
Survey Results ◽  
Rot Disease ◽  
One Year

An extensive survey conducted in the Saïss plain of Morocco during the 2017–2018 growing season revealed that 35 out of 50 apple and pear orchards were infested with a pathogen that causes the decline disease. Morphological and phylogenetic tree analyses using the cox II gene allowed us to identify the pathogen as Phytopythium vexans. Interestingly, no Phytophthora and Pythium species were isolated. The occurrence and prevalence of the disease varied between locations; the most infested locations were Meknes (100%), Imouzzer (83%), and Sefrou (80%). To fulfill Koch’s postulate, a greenhouse pathogenicity test was performed on the stem and collar of one-year-old healthy seedlings of apple rootstock M115. Symptoms similar to those observed in the field were reproduced in less than 4 months post-inoculation with root rot disease severity ranging from 70 to 100%. The survey results evidenced that apple rootstocks, soil type, and irrigation procedure may contribute significantly to the occurrence of the disease. The disease was most prevalent in drip water irrigation and sandy-clay soil on wild apple rootstock. Accordingly, a rational drip advanced watering system and good sanitation practices could eliminate water stagnation and help prevent the onset of this disease. It was concluded that Pp. vexans occurrence may be strongly influenced by irrigation mode and type of soil. Therefore, the obtained findings of this study could help to better understand the recurrence of this disease and to develop a reliable integrated strategy for its management.

scholarly journals Chestnut Leaf Inoculation Assay as a Rapid Predictor of Blight Susceptibility

Plant Disease ◽  
2014 ◽  
Vol 98 (1) ◽  
pp. 4-9 ◽  
Author(s):  
Andrew E. Newhouse ◽  
Jesse E. Spitzer ◽  
Charles A. Maynard ◽  
William A. Powell
Keyword(s):  
Cryphonectria Parasitica ◽  
Castanea Dentata ◽  
Blight Resistance ◽  
Mature Trees ◽  
Screening Process ◽  
The Subject ◽  
Old Trees ◽  
Individual Trees ◽  
Chestnut Leaf ◽  
Inoculation Assay

American chestnuts (Castanea dentata), effectively eliminated from eastern North America by chestnut blight in the twentieth century, are the subject of multiple restoration efforts. Screening individual trees (or tree types) for blight resistance is a critical step in all of these programs. Traditional screening involves inoculating stems of >3-year-old trees with the blight fungus (Cryphonectria parasitica), then measuring resulting cankers a few months later. A quicker, nondestructive, quantitative assay, usable on younger plants, would enhance restoration efforts by speeding the screening process. The assay presented here meets these requirements by inoculating excised leaves with the blight fungus and measuring resulting necrotic lesions. Leaves can be collected from few-month-old seedlings or fully mature trees, and results are measured after less than a week. Leaves from several lines of both American and Chinese chestnuts were inoculated, as well as the congener Allegheny chinquapin, and experimental leaf assay results correlate well with stem assay results from these species. Inoculations with virulent and hypovirulent blight fungi strains also showed relative patterns similar to traditional inoculations. Given the correlations to established stem assay results, this procedure could be a valuable tool to quickly evaluate blight resistance in American chestnut trees used for restoration.

The epidemiology of common root rot in Manitou wheat: disease progression during the growing season

1974 ◽  
Vol 52 (7) ◽  
pp. 1757-1764 ◽  
Author(s):  
P. R. Verma ◽  
R. A. A. Morrall ◽  
R. D. Tinline
Keyword(s):  
Triticum Aestivum ◽  
Disease Severity ◽  
Plant Development ◽  
Root Rot ◽  
Growing Season ◽  
Cochliobolus Sativus ◽  
Infection Rates ◽  
Common Root ◽  
Common Root Rot ◽  
Disease Rating

Common root rot in Triticum aestivum cultivar Manitou caused primarily by Cochliobolus sativus was followed during plant development in 1969, 1970, and 1971 at Matador, Saskatchewan. Plants were sampled at intervals, and three variables based mainly on the occurrence of lesions on subcrown internodes were studied: number of diseased plants per square meter; percentage of diseased plants; and disease rating which integrated percentage of diseased plants and disease severity on each plant. All variables increased with time, and the progression curves in all 3 years were hyperbolic, indicating that the increases were like those of a simple interest disease as described by Van der Plank. In two of the years, almost 100% of the plants were diseased considerably before the end of the season. The transformation proposed by Van der Plank for simple interest diseases, log10[1/(1 − x)], was applied to the percentages of diseased plants, and regressions were calculated. The slopes of these lines (infection rates) were as follows: 1969, 0.99% plants per day; 1970, 1.32%; and 1971, 1.96%. In 1969 the onset of disease was later than in 1970 and 1971, and there was correspondingly less disease at the end of the growing season.

scholarly journals The Influence of Rooting Substrate and Growth Regulators Indol butyric Acid and Naphthalene Acetic Acid in the Number and Length of Adventitious Roots to Hardwood Cuttings in Blueberry cv. ‘Bluecrop’ (Vaccinium corymbosum L.)

2016 ◽  
Vol 4 (4) ◽  
pp. 28
Author(s):  
Sabri Braha ◽  
Petrit Rama
Keyword(s):  
Growth Regulators ◽  
Growing Season ◽  
Vaccinium Corymbosum ◽  
Naphthalene Acetic Acid ◽  
Important Variation ◽  
Physiological Processes ◽  
One Year ◽  
The Impact ◽  
Better Than

The purpose of this research is to determine the impact of the turf-only substrate and turf–perlite in the ratio 2:1 and of growth regulators in the quality of adventive roots ( the number and length) of well lignified one-year old branches without fruit buds in the Bluecrop cultivar (Vaccinium corymbosum L.) taken at the end of the latent period before budding at the February 15 th during the -2015 growing season. In order to support the increase of the number of roots and their length the hardwood cuttings are treated with different IBA and NAA concentrations (1500, 3000, 4500 ppm), while a part of cuttings were untreated control. The number and the length of roots have increased in relation to the increase of concentration from 1500 to 3000 ppm followed by a decline of these values in concentrations over 3000 ppm. Respectively, the number of roots (8) and the higher values of root length (4.6 cm) are achieved in the turf–perlite substrate, IBA 3000 ppm (compared to the turf-only substrate). The presence of perlite helps the aeration of the substrate and supports biochemical and physiological processes which lead to the inducing of adventive roots. Regarding the number and length of roots an important variation for (p<0.05) was observed between different concentrations of IBA and NAA. In general the effect of IBA was a lot better than the effect of NAA.

scholarly journals Preliminary Findings of New Citrus Rootstocks Potentially Tolerant to Foot Rot Caused by Phytophthora

Horticulturae ◽  
2021 ◽  
Vol 7 (10) ◽  
pp. 389
Author(s):  
Lidia Aparicio-Durán ◽  
Juan M. Arjona-López ◽  
Aurea Hervalejo ◽  
Rocío Calero-Velázquez ◽  
Francisco J. Arenas-Arenas
Keyword(s):  
Root Rot ◽  
Brown Rot ◽  
Lesion Length ◽  
Post Inoculation ◽  
Foot Rot ◽  
Damping Off ◽  
Citrus Industry ◽  
Breeding Programs ◽  
Phytophthora Spp ◽  
Branch Canker

Phytophthora spp. are one the most common soil-borne pathogens in citrus crops, in which Phytophthoranicotianae and P. citrophthora are the most relevant species, causing disease problems worldwide, such as foot rot and gummosis of the trunk, branch canker, brown rot of fruit, feeder root rot in orchards, and seedling damping-off in nurseries. Phytophthora-tolerant citrus rootstocks are essential for its control and for the success of the citrus industry. The aim of this study was to determine the susceptibility of new citrus rootstocks with low HLB incidence to Phytophthora diseases. Thus, plants of several commercial and new citrus rootstocks originating in different breeding programs were inoculated with an isolate of P. nicotianae. Thirty days post inoculation (DPI), the damage of lesion length in stem was measured for each plant. These results displayed a different susceptibility response to the damage caused by P. nicotianae among the citrus rootstocks tested. Thus, eleven new citrus rootstocks (B11R3T25, B11R5T25, B11R5T49, B11R5T60, B11R5T64, N40R1T18, N40R1T19, N40R3T25, WGFT + 50-7, UFR-6, and CL-5146), which have not been previously studied against Phytophthora diseases, improved the tolerance effect of Carrizo citrange. Our findings provide useful information for citrus growers on rootstock selection to address incidence problems caused by Phytophthora spp.

scholarly journals Hard Mast Production Before and After the Chestnut Blight

2000 ◽  
Vol 24 (4) ◽  
pp. 196-201 ◽  
Author(s):  
Seth J. Diamond ◽  
Robert H. Giles ◽  
Roy L. Kirkpatrick ◽  
Gary J. Griffin
Keyword(s):  
Carrying Capacity ◽  
Basal Area ◽  
Cryphonectria Parasitica ◽  
Castanea Dentata ◽  
Chestnut Blight ◽  
Wildlife Species ◽  
Chestnut Blight Fungus ◽  
Southern Appalachian ◽  
Before And After ◽  
Mast Production

Abstract We estimated hard mast production of a Southern Appalachian forest for two 10 yr intervals: one before and one, 35 yr after, the chestnut blight fungus (Cryphonectria parasitica) (Murr.) Barr, had killed all mature chestnut trees. The basal area of hard mast-producing trees in the postblight forest was 28% less than in the preblight forest. The estimate of hard mast output was 34% less after the chestnut blight. Postblight production was less than preblight production for 8 of 10 yr. During 5 of these years, postblight production was only 5-27% of preblight production. Annual preblight mast production was relatively stable, whereas annual postblight production fluctuated substantially. Our findings suggest that the loss of mature chestnuts (Castanea dentata) markedly reduced the Southern Appalachian forest's carrying capacity for certain wildlife species. South. J. Appl. For 24(4):196-201.

Third-Year Growth Response of Loblolly Pine to Eight Levels of Competition Control

1987 ◽  
Vol 11 (2) ◽  
pp. 91-95 ◽  
Author(s):  
Catherine G. Bacon ◽  
Shepard M. Zedaker
Keyword(s):  
Loblolly Pine ◽  
Growth Response ◽  
Volume Growth ◽  
Growing Season ◽  
Control Treatment ◽  
Growing Seasons ◽  
Best Response ◽  
Competition Control ◽  
Pinus Taeda L ◽  
One Year

Abstract The growth response of young loblolly pine (Pinus taeda L.) to different amounts of competition control was studied in plantations of three ages in the Virginia Piedmont. Eight competition control treatments involved the removal of all, two-thirds, one-third, or none of the hardwoodstems either with or without herbaceous weed control. Results after three growing seasons showed a significant increase in pine diameter and volume growth with competition control. Treatments combining woody and herbaceous control resulted in better pine growth than the same treatments withoutherbaceous control, in the two youngest stands. The best response, obtained with the two-thirds woody plus herbaceous control treatment, resulted in: a 100% increase in volume growth over the check plots in seedlings treated at the beginning of their second growing season in the field; a 93% increase in one-year-old seedlings; and a 53% increase in the growth of seedlings treated before the third growing season. South. J. Appl. For. 11(2):91-95.

Ex situ conservation of American chestnut (Castanea dentata (Marsh.) Borkh.) and butternut (Juglans cinerea L.), a review

2000 ◽  
Vol 76 (5) ◽  
pp. 765-774 ◽  
Author(s):  
Ken McIlwrick ◽  
S. Wetzel ◽  
T. Beardmore ◽  
K. Forbes
Keyword(s):  
Genetic Information ◽  
Ex Situ Conservation ◽  
In Situ Conservation ◽  
Cryphonectria Parasitica ◽  
Castanea Dentata ◽  
American Chestnut ◽  
Ex Situ ◽  
Juglans Cinerea ◽  
Research Areas

Two tree species native to North America, American chestnut (Castanea dentata (Marsh.) Borkh.) and butternut (Juglans cinerea L.), which have experienced rapid declines in their populations due to similar stressors (disease and changes in land use), are used as examples of how these species would benefit from ex situ conservation efforts. Current and past ex situ and in situ conservation efforts for these species are discussed and the focus of this review is on two key research areas: 1) what needs to be preserved (genetic information) and 2) how to preserve these trees or germplasm. Key words: butternut, American chestnut, Cryphonectria parasitica, Sirococcus clavigignenti-juglandacearum, ex situ conservation

Competition for nodule occupancy of introduced Bradyrhizobium japonicum strains in a Wisconsin soil with a low indigenous bradyrhizobia population

1990 ◽  
Vol 36 (12) ◽  
pp. 839-845 ◽  
Author(s):  
T. J. McLoughlin ◽  
S. Hearn ◽  
S. G. Alt
Keyword(s):  
Bradyrhizobium Japonicum ◽  
Growing Season ◽  
Field Trials ◽  
Enzyme Linked Immunosorbent Assay ◽  
Nodule Occupancy ◽  
Antibiotic Resistant ◽  
Growing Seasons ◽  
Low Incidence ◽  
One Year ◽  
Successful Inoculation

The population dynamics of six introduced Bradyrhizobium japonicum strains were measured over three growing seasons in a Wisconsin soil with a low incidence of indigenous B. japonicum (10 cells/gm). Four antibiotic-resistant members of the 123 serocluster (which were either spectinomycin resistant or streptomycin resistant), USDA 110, and USDA 138 were inoculated using liquid inoculum, at a rate of 1 × 108 cells per 2.5-cm row, on two soybean cultivars in 1985. Nodule occupants were identified using an enzyme-linked immunosorbent assay (ELISA), fluorescent antibodies, and antibiotic-resistant mutants. In the first growing season, 100% of the nodules were formed by the introduced strains. The nodules from the uninoculated plots were occupied by an indigenous 110 serogroup. In the second and the third season at the same site (without further inoculation), a high percentage (> 60%) of the nodules from all the plots were nodulated by the 123 serocluster (either alone or as mixed infections). However, < 25% of the nodules in the 123-inoculated plots and < 9% in the other plots were formed by any of the antibiotic-marked 123 inoculum strains introduced in 1985. The main conclusions are (i) that it is possible to successfully introduce inoculum strains in soils where the indigenous Bradyrhizobium population is low and to obtain 100% nodule occupancy in the first growing season, and (ii) that successful inoculation in one year in soils with a low incidence of Bradyrhizobium does not ensure that the introduced inoculum strains will form nodules in subsequent years. Key words: Bradyrhizobium japonicum, indigenous bradyrhizobia, interstrain competition, field trials.

Sign in / Sign up

Export Citation Format

Share Document