scholarly journals The Influence of Light on Relationships Between Sclerotinia Stem Rot of Soybean in Field and Controlled Environments

Plant Disease ◽  
2008 ◽  
Vol 92 (11) ◽  
pp. 1510-1514 ◽  
Author(s):  
A. J. Peltier ◽  
C. R. Grau

Interaction phenotypes between soybean and Sclerotinia sclerotiorum observed in controlled and field environments often do not correlate. Resistant and susceptible accessions were selected to study light intensity as a variable that influences interaction phenotype. Objectives were to investigate whether light intensity within a controlled environment influences the ability to: i) distinguish resistant and susceptible accessions; ii) predict field interaction phenotypes; and iii) determine whether the method used for disease assessment influences the outcome of results. Six accessions were evaluated in growth chamber and field disease nursery trials. Five environments ranging from 146 to 434 μmol·m–2·s–1 of photosynthetically active radiation were established in the growth chamber. Inoculum was delivered to cut petioles at the R1 growth stage and interaction phenotypes were assessed for 11 days. For field trials, individual plants were rated at growth stage R7. The breeding line W04.1002 had less disease than NK S19-90 in field environments. Rank correlations of field and light environment interaction phenotypes indicate that light intensity affected the prediction of field performance. Evaluations conducted at 337 μmol·m–2·s–1 of light were most predictive of field interaction phenotypes (rs = 0.83 to 0.94; P = 0.05 to < 0.005). Controlling light intensity is critical to facilitate the identification of resistance to S. sclerotiorum in soybean.

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 621c-621
Author(s):  
Mark W. Farnham ◽  
Anthony P. Keinath

Wirestem, caused by Rhizoctonia solani, is a destructive disease of B. oleracea cole crops and is distributed worldwide. Effective means of wirestem control include soil fumigation and soil treatment with pentachloronitrobenzene, which are increasingly expensive and environmentally undesirable. As a consequence, alternative methods of wirestem control are needed. Thus, we conducted controlled-environment and field experiments to develop methodology to study host-plant resistance and possibly biocontrol agents as potential wirestem control alternatives. Seedlings of 12 cultivars (three each of cauliflower, broccoli, cabbage, and collard) at the four- to five-leaf stage were transplanted to trays in a growth room or into field plots and covered with soil infested with R. solani AG-4 sclerotia. Disease progression (percent of plants healthy, diseased, and dead) was observed every 3 days for 2 weeks in the controlled environments and for 3 weeks in field trials. At the end of two studies, plants were dug with roots intact and rated for disease using a 1 to 10 scale. In all trials, percent healthy plants stabilized at about 2 weeks after inoculation. Incidence of wirestem disease varied among experiments ranging from 70% to 100% diseased, dead plants in controlled environments, and from 51% to 88% and 33% 65% in the two respective field studies. Disease rating was always negatively and significantly correlated with percent healthy plants. Although a genotype × environment interaction was observed, some cultivars (i.e., `Snowcone' and `Snowcrown' cauliflowers) were always severely diseased, while others (i.e., `Viking' broccoli and `Blue Max' collard) were consistently among the least diseased.


Author(s):  
Anna Langstroff ◽  
Marc C. Heuermann ◽  
Andreas Stahl ◽  
Astrid Junker

AbstractRising temperatures and changing precipitation patterns will affect agricultural production substantially, exposing crops to extended and more intense periods of stress. Therefore, breeding of varieties adapted to the constantly changing conditions is pivotal to enable a quantitatively and qualitatively adequate crop production despite the negative effects of climate change. As it is not yet possible to select for adaptation to future climate scenarios in the field, simulations of future conditions in controlled-environment (CE) phenotyping facilities contribute to the understanding of the plant response to special stress conditions and help breeders to select ideal genotypes which cope with future conditions. CE phenotyping facilities enable the collection of traits that are not easy to measure under field conditions and the assessment of a plant‘s phenotype under repeatable, clearly defined environmental conditions using automated, non-invasive, high-throughput methods. However, extrapolation and translation of results obtained under controlled environments to field environments is ambiguous. This review outlines the opportunities and challenges of phenotyping approaches under controlled environments complementary to conventional field trials. It gives an overview on general principles and introduces existing phenotyping facilities that take up the challenge of obtaining reliable and robust phenotypic data on climate response traits to support breeding of climate-adapted crops.


2007 ◽  
Vol 37 (3) ◽  
pp. 515-522 ◽  
Author(s):  
Tore Skrøppa ◽  
Ketil Kohmann ◽  
Øystein Johnsen ◽  
Arne Steffenrem ◽  
Øyvind M. Edvardsen

We present results from early tests and field trials of offspring from two Norway spruce ( Picea abies (L.) Karst.) seed orchards containing clones that have been transferred from high altitudes to sea level and from northern to southern latitudes. Seedlings from seeds produced in the low-altitude seed orchard developed frost hardiness later at the end of the growth season, flushed later in field trials, and grew taller than seedlings from seeds produced in natural stands. They had the lowest mortality rate and the lowest frequency of injuries in the field trials. Similar results were observed in seedlings from seeds produced in the southern seed orchard. We found no adverse effects of the changed growth rhythm. Seedlings from two seed crops in the southern orchard, produced in years with a warm and a cold summer, had different annual growth rhythms. The results are explained mainly by the effects of the climatic conditions during the reproductive phase. Seed crops from different years in the same seed orchard may produce seedlings that perform as if they were from different provenances. It is argued that the effects of the climatic conditions during seed production must contribute to the variation among provenances of Norway spruce.


Weed Science ◽  
1970 ◽  
Vol 18 (4) ◽  
pp. 509-514 ◽  
Author(s):  
Lafayette Thompson ◽  
F. W. Slife ◽  
H. S. Butler

Corn(Zea maysL.) in the two to three-leaf stage grown 18 to 21 days in a growth chamber under cold, wet conditions was injured by postemergence application of 2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine (atrazine) plus emulsifiable phytobland oil. Injury was most severe when these plants were kept under cold, wet conditions for 48 hr after the herbicidal spray was applied, followed by exposure to high light intensity and high temperature. Under these growth chamber conditions, approximately 50% of the atrazine-treated plants died. Since wet foliage before and after application increased foliar penetration and low temperature decreased the rate of detoxication to peptide conjugates, atrazine accumulated under cold, wet conditions. This accumulation of foliarly-absorbed atrazine and the “weakened” conditions of the plants grown under the stress conditions is believed to be responsible for the injury to corn. Hydroxylation and the dihydroxybenzoxazin-3-one content in the roots were reduced at low temperature, but it is unlikely that this contributed to the death of the corn.


Author(s):  
Darcy E. P. Telenko ◽  
Martin I. Chilvers ◽  
Adam Byrne ◽  
Jill Check ◽  
Camila Rocco Da Silva ◽  
...  

Tar spot of corn caused by Phyllachora maydis has recently led to significant yield losses in the eastern corn belt of the Midwestern United States. Foliar fungicides containing quinone outside inhibitors(QoI), demethylation inhibitors(DMI), and succinate dehydrogenase inhibitors(SDHI) are commonly used to manage foliar diseases in corn. To mitigate the losses from tar spot thirteen foliar fungicides containing single or multiple modes of action (MOA/FRAC groups) were applied at their recommended rates in a single application at the standard tassel/silk growth stage timing to evaluate their efficacy against tar spot in a total of eight field trials in Illinois, Indiana, Michigan, and Wisconsin during 2019 and 2020. The single MOA fungicides included either a QoI or DMI. The dual MOA fungicides included a DMI with either a QoI or SDHI, and fungicides containing three MOAs included a QoI, DMI, and SDHI. Tar spot severity estimated as the percentage of leaf area covered by P. maydis stroma of the non-treated control at dent growth stage ranged from 1.6 to 23.3% on the ear leaf. Averaged across eight field trials all foliar fungicide treatments reduced tar spot severity, but only prothioconazole+trifloxystrobin, mefentrifluconazole+pyraclostrobin+fluxapyroxad, and mefentrifluconazole+pyraclostrobin significantly increased yield over the non-treated control. When comparing fungicide treatments by the number of MOAs foliar fungicide products that had two or three MOAs decreased tar spot severity over not treating and products with one MOA. The fungicide group that contained all three MOAs significantly increased yield over not treating with a fungicide or using a single MOA.


Plant Disease ◽  
2008 ◽  
Vol 92 (8) ◽  
pp. 1197-1200 ◽  
Author(s):  
V. N. Bilgi ◽  
C. A. Bradley ◽  
S. D. Khot ◽  
K. F. Grafton ◽  
J. B. Rasmussen

Fusarium root rot of dry bean (Phaseolus vulgaris), caused by Fusarium solani f. sp. phaseoli, is a major yield-limiting disease in North Dakota and Minnesota. Although a few sources of partial resistance are available, most commercial cultivars grown in this region are susceptible, especially in the red kidney bean market class. This study evaluated three methods of screening for resistance to Fusarium root rot. A sand-cornmeal inoculum layer method, spore suspension method, and paper towel method were used to evaluate 11 dry bean genotypes for resistance to Fusarium root rot under growth-chamber conditions. These same genotypes were also evaluated in field trials at Fargo, ND, and Park Rapids and Perham, MN, in 2005. In all trials, the small red genotype VAX 3 was found to have a consistently high level of resistance to Fusarium root rot and could be used as a source of resistance by dry bean breeders. Correlation analyses between field and growth-chamber root rot ratings indicated that all three growth-chamber methods had significantly (P ≤ 0.05) positive correlations with field results from Perham and Fargo, which suggests that all three methods could be used to screen germplasm efficiently for resistance to Fusarium root rot.


1967 ◽  
Vol 7 (29) ◽  
pp. 489 ◽  
Author(s):  
DF Cameron

The flowering of seven selections of Townsville lucerne (Stylosanthes humilis HBK) representing a range of maturity types has been studied in the Canberra phytotron. Daylength is the main factor controlling flowering in these selections, all of which showed a strong short day response. At normal temperatures the maximum daylengths at which all plants flowered (the critical daylengths) were 13 hours for the early, 12 hours for the midseason and late-midseason, and 11 1/2 hours for the late selections. However, the midseason selections did flower in a 12 1/2-hour daylength if the light intensity of the supplementary illumination was 20 or 5 ft.c. instead of the normal 50 ft.c. The response of the other selections was not altered at the lower light intensities. Both high night temperature and low day temperature delayed or inhibited flower initiation in the early and midseason selections and these effects were greater at a critical daylength.


1969 ◽  
Vol 90 (3-4) ◽  
pp. 193-206
Author(s):  
Linda Wessel-Beaver ◽  
Obed Román-Hernández ◽  
Luisa E. Flores-López

New tropical pumpkin (Cucurbita moschata Duchesne) genotypes were evaluated for yield, flesh (mesocarp) color, pest resistance and seed production as compared with the standard cultivar Soler in six field trials at three Puerto Rico locations during a two-year period (2003-2005). Genotypes included an open-pollinated population (PRShortvine-1) and four lines (E0305-1, E0305-2, E0305-3 and E0305-4) with a semi-bush growth habit, as well as a new long-vine open-pollinated population (PRLongvineSLR). Various within-row (0.9- and 1.9-m) and between-row (1.9- and 3.8-m) planting distances were tested. Not all genotypes nor planting distances were included in each trial. PRLongvineSLR was partially resistant to the melonworm (Diaphania hyalinata), whereas lines E0305-1 and E0305-2 were very susceptible. These same lines, as well as PRShortvine-1, were also susceptible to downy mildew, Pseudoperonospora cubensis. All genotypes produced similar yields. Within-row planting distance generally had no effect on fruit weight, fruit number and yield. All new genotypes had good flesh thickness (>4 cm) and small fruit cavities. Flesh color of PRShortvine-1 and PRLongvineSLR tended to be more orange than that of Soler. Lines E0305-3 and E0305-4 had poor seed production, whereas seed production in fruits of PRShortvine-1 and PRLongvineSLR was similar to that of Soler. Despite some shortcomings, PRShortvine-1 and PRLongvineSLR are two advanced open-pollinated populations that should be considered for formal release on the basis of their field performance, good fruit quality and ability to produce profitable amounts of seed in a seed production program. 


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