Effect of soil temperature on the pathology of Alternaria radicina on carrots

1977 ◽  
Vol 55 (10) ◽  
pp. 1410-1418
Author(s):  
W. G. Benedict

The temperature of muck soil infested with Alternaria radicina Meier, Drechsler, and Eddy was found to have a marked effect upon the severity of root dieback or rusty root of carrots, Daucus carota L. When the surface of steam-sterilized muck soil was artificially reinfested with as few as 50 spores of A. radicina per square centimetre, less than 1% emergence occurred below 18 °C in controlled soil-temperature experiments. In muck soil naturally infested with A. radicina, carrot seedling emergence over the whole range of temperatures, 10–28 °C, was little more than half that obtained in steam-sterilized similar soil. The severity of root dieback increased sharply with decreasing temperature below 18 °C in both artificially reinfested and naturally infested soil. Alternaria radicina was found actively growing on carrots in naturally infested soil at and below 16 °C, but, when similar soil was steam sterilized and artificially reinfested after seedling emergence, A. radicina infected the young carrots in soil up to 26 °C. Alternaria radicina was consistently isolated both from carrots with symptoms of root dieback or rusty root and from the muck soil in which the carrots had been grown and had produced symptoms of root dieback or rusty root. An analysis of variance of the root weight data of the five cultivars of carrots used showed that the effect of soil temperature was independent of the effect of the infested soil on root growth. A multivariate analysis of variance affecting all means of root weight of the five cultivars showed that, in general, any selected number of carrot cultivars would each vary in root weight according to the soil temperature and to the infested soil significantly and independently.

Nematology ◽  
2002 ◽  
Vol 4 (3) ◽  
pp. 381-386
Author(s):  
Christopher Steel ◽  
John Kirkegaard ◽  
Rod McLeod

AbstractThe effects of seed treatments with pesticides, soil temperature at sowing, cutting of plants with and without glyphosate herbicide, root disruption and age of crop at inoculation on reproduction of Meloidogyne javanica on Brassica napus were investigated. When inoculated at sowing, plants grown from fodder rape cv. Rangi seed treated with fenamiphos (0.35 g a.i. per 100 g) and from fodder swede cv. Highlander seed with a coating including imidacloprid had fewer galls than plants from seed untreated or treated with omethoate (0.7 g a.i. per 100 g). When nematode inoculation was delayed until 4 weeks after sowing, omethoate and the imadacloprid treatments had no effect while fenamiphos (0.7 g a.i. per 100 g seed) suppressed galling but also impaired seedling emergence and induced chlorosis. Green manure rape plants cvs Rangi and Humus transplanted into infested soil in the field in mid-autumn (soil temperature 17°C) remained nematode and gall-free, but tomato cv. Grosse Lisse plants were heavily galled. All three cultivars were gall-free when transplanted and grown in early winter (soil temperatures 8-14°C). Cutting off the tops of cv. Rangi plants at from 6 to 11 weeks after sowing and inoculation had no effect on egg production compared to that on intact plants. Predominant nematode stages in cut plants ranged from developing juveniles to egg-laying females. Application of glyphosate to freshly cut stems had no effect on egg production at any stage. Infesting soil with roots of cv. Rangi, finely chopped while nematodes in them were still juveniles, resulted in a low incidence of infection of bioassay tomato plants compared with infesting soil with rape roots chopped later, when females and females with eggs predominated. Young females in tomato roots laid eggs despite fine chopping of the roots. When cv. Rangi plants were inoculated at 3, 5 and 7 weeks after sowing, the 7-week-old plants were the least invaded and fewer eggs were produced on the 5 and 7-week-old plants than on the 3-week-old ones.


1981 ◽  
Vol 96 (3) ◽  
pp. 549-556 ◽  
Author(s):  
P. J. Salter ◽  
I. E. Currah ◽  
Jane R. Fellows

SUMMARYFive investigations were carried out to determine the magnitude of root-size variation within crops of cv. Chantenay Supreme grown under competitive and non-competitive conditions, and to study possible sources of inter-plant variation.In the first experiment root-size variation from crops grown at a high population density (245 plants/m2) and at a low density (25 plants/m2) were compared over a 21-week period from sowing. The c.v.s of root weight were always higher from the high density than from the low density over the harvesting period from 11 to 21 weeks after sowing, and ranged from 74 to 94% and from 50 to 63%, respectively. A second study showed that even with a very low population density (3 plants/m2) the c.v. of root weight at harvest was 58%. The third study showed that 40% of the root weight variation was accounted for by the time of seedling emergence. The results of a pot experiment indicated that when the size of seed, sowing depth, rooting medium and time of seedling emergence were made as uniform as possible, a very uniform population of roots was produced with a c.v. of root weight of 32%. In the final field experiment when time of seedling emergence, seed size and spatial distribution of the plants were the experimental variables, the results confirmed the importance of variability in time of seedling emergence and seedling size in creating variation at an early stage of growth.The results of these studies indicate that competition per se was not a prime source of variation in root size but magnified any initial variation within the crop at the time of seedling establishment. The importance of this early establishment phase in determining the spread of root-size distribution within a crop is discussed together with the factors which influence the time of seedling emergence and seedling size.


2021 ◽  
Vol 888 (1) ◽  
pp. 012009
Author(s):  
F Mustofa ◽  
A P Z N L Sari ◽  
A Agus ◽  
H Sasongko ◽  
E Suryanto ◽  
...  

Abstract The production of local chickens in Indonesia is determined by the availability of high-quality local chicken stocks. However, information on local chicken performance is limited, therefore, this study aims to determine the live weight performance of three local Indonesian chicken namely Merawang, Murung Panggang, and KUB in the starter phase. The study was conducted at chicken farm located in Semanu Gunung Kidul, Yogyakarta. Meanwhile, the live weight data were collected at the starter phase (0, 2, and 4 weeks. The samples consisted of 196 Merawang, 157 Murung Panggang, and 416 KUB chickens reared in a battery cage in a closed house under similar conditions. Furthermore, the live weight performance data were analyzed using analysis of variance (ANOVA). As a result, the Merawang chicken had the highest live weight (P<0.05) at the day-old chick (DOC) age. At the same age, no significant difference was detected between the KUB and Murung Panggang chicken (P>0.05). However, the live weight of Murung Panggang was significantly higher at 2 and 4 weeks compared to others (P< 0.05). Therefore, it was concluded that there are variations in the live weight of the three local chickens during the starter phase.


1972 ◽  
Vol 37 (2) ◽  
pp. 441-444 ◽  
Author(s):  
N. T. Singh ◽  
G. S. Dhaliwal

2021 ◽  
Vol 6 (1) ◽  
pp. 826-835
Author(s):  
Habtamu Tegen ◽  
Mnuyelet Jembere

Abstract Although there is adequate information on the influence of plant population on root yield and size of carrot on flat and raised bed for rain fed production system, information on ridge-furrow bed preparation method is limited for irrigation production system. Therefore, in this study, field experiments were conducted for 2 years to determine the appropriate spacing of carrot on ridge-furrow carrot production practice under irrigation. Root yield increased significantly as the population increased. On the contrary, root size significantly decreased as population increased. The result of combined analysis over season and locations indicated that the narrowest spacing of 10 cm × 4 cm rows on the ridge and between plants, respectively, which accommodates 1,250,000 plants ha−1 gave significantly highest marketable carrot root yield of 26 t ha−1 followed by 22.6 t ha−1 with spacing of 20 cm × 4 cm which accommodates 1,000,000 plants ha−1, but it produced the smallest individual root weight of 83 g which is mostly preferred for household consumption unlike jumbo roots. Therefore, in terms of root sizes and marketable yield, the current study identified that spacing of 10 cm × 4 cm is optimum on ridge-furrow carrot production practices.


1962 ◽  
Vol 42 (3) ◽  
pp. 481-487 ◽  
Author(s):  
S. Dubetz ◽  
G. C. Russell ◽  
D. T. Anderson

Rate and percentage of emergence of 19 native and cultivated herbaceous species were studied at the following soil temperature: 6°, 13°, 18°, and 24 °C. The soil temperatures were held uniformly constant, and emergence data at the end of 5 weeks from four replications in time were obtained. The rate of emergence of all species was greater at 18 °C. than at 6 °C., and of all but five species was greater at 24 °C. than at 18 °C.The percentage of emergence of barley, bromegrass, crested wheatgrass, mustard, oats, peas, spring wheat, and wild oats was not significantly affected by soil temperature. Beans, corn, sugar beets, and sunflowers showed significantly lower emergence percentages at 6 °C. than at the three higher soil temperatures. Alfalfa, creeping red fescue, winter wheat, orchardgrass, rough fescue, sweet clover, and flax emerged best at moderate soil temperatures.


Weed Research ◽  
1990 ◽  
Vol 30 (2) ◽  
pp. 91-99 ◽  
Author(s):  
R. L. BENECH ARNOLD ◽  
C. M. GHERSA ◽  
R. A. SANCHEZ ◽  
P. INSAUSTI

2016 ◽  
Vol 28 (2) ◽  
pp. 151-164 ◽  
Author(s):  
Sylwester Smoleń ◽  
Łukasz Skoczylas ◽  
Iwona Ledwożyw-Smoleń ◽  
Roksana Rakoczy ◽  
Marta Liszka-Skoczylas ◽  
...  

AbstractThe aim of the study was to evaluate the influence of various chemical forms of iodine (I−and IO3−) and selenium (SeO32−and SeO42−) on the nutritional and health-promoting quality of carrot (Daucus carotaL.) storage roots. The experiment (conducted in 2012-2014) comprised the soil fertilization of carrot ‘Kazan’ F1in the following combinations: 1. Control, 2. KI, 3. KIO3, 4. Na2SeO4, 5. Na2SeO3, 6. KI + Na2SeO4, 7. KIO3+ Na2SeO4, 8. KI + Na2SeO3, 9. KIO3+ Na2SeO3. Iodine and selenium were applied twice: before sowing and as top dressing in a total dose of 5 kg I ha−1and 1 kg Se ha−1. No significant influence of iodine and selenium fertilization was noted with respect to average root weight and leaf yield. Each year, the application of KI + Na2SeO4negatively affected the content of glucose and total sugars in carrot. An increased sucrose level was noted in the roots of plants treated with KIO3+ Na2SeO4, with a total sugar concentration comparable to the control. Irrespective of the year, carrots fertilized with KI were characterized by the highest accumulation of nitrates (III) – NO2−in roots. The simultaneous introduction of iodine and selenium compounds (KI + Na2SeO4, KIO3+ Na2SeO4, KI + Na2SeO3and KIO3+ Na2SeO3) into the soil reduced the content of nitrates (III) in carrot as compared to combinations with the individual application of these compounds. The influence of the tested factors on other analysed parameters (the content of dry weight, nitrates (V), chlorides, oxalates, citrates, free amino acids, carotenoids, phenolic compounds, phenylpropanoids, flavonols and anthocyanins as well as free radical scavenging activity (DPPH) was rather year-dependent.


Plant Disease ◽  
2006 ◽  
Vol 90 (5) ◽  
pp. 597-602 ◽  
Author(s):  
M. T. Kirkpatrick ◽  
C. S. Rothrock ◽  
J. C. Rupe ◽  
E. E. Gbur

The effect of flooding and Pythium ultimum on soybean, Glycine max, was determined in a series of greenhouse experiments using the cultivars Hutcheson and Archer. Seeds were planted into pasteurized soil either not infested or infested with sand-cornmeal inoculum of P. ultimum and either flooded at emergence for 2 days or at the four leaf node stage (V4) for 5 days. A nonflooded control was included in each experiment. Seeds placed directly into infested soil resulted in little or no stand for Hutcheson regardless of flood treatment, whereas stand was reduced for Archer only in the flooded infested soil treatment. Additional experiments were conducted by placing seed onto a 2- to 5-mm layer of pathogen-free soil on top of the infested soil. Flooding at emergence reduced plant height, growth stage, and top dry weight for Hutcheson and root fresh weight for both cultivars. Greater reductions for Hutcheson in root weight, and top dry weight in P. ultimum-infested soil in the soil layer experiments, also indicated that Hutcheson was more susceptible than Archer. Flooding alone decreased root weights, and infestation with P. ultimum reduced weights further resulting in an additive effect. This also was the case for plant height, growth stage, and top dry weight for Hutcheson for flooding at emergence. Root discoloration was greatly increased for both cultivars in infested soil flooded at emergence. Similar results were found when plants were flooded at V4; however, the effect was not as great as with flooding at emergence. These studies indicate that Pythium damping-off and root rot may account for a portion of the negative response of soybean to flooding. The results also indicate that Archer has some resistance to P. ultimum.


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