| 1. |
- Ali, Ashfaq, et al.
(författare)
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Paranoid potato : phytophthora-resistant genotype shows constitutively activated defense
- 2012
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Ingår i: Plant Signaling and Behavior. - : Informa UK Limited. - 1559-2316 .- 1559-2324. ; 7:3, s. 400-408
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Tidskriftsartikel (refereegranskat)abstract
- Phytophthora is the most devastating pathogen of dicot plants. There is a need for resistance sources with different modes of action to counteract the fast evolution of this pathogen. In order to better understand mechanisms of defense against P. infestans, we analyzed several clones of potato. Two of the genotypes tested, Sarpo Mira and SW93-1015, exhibited strong resistance against P. infestans in field trials, whole plant assays and detached leaf assays. The resistant genotypes developed different sizes of hypersensitive response (HR)-related lesions. HR lesions in SW93-1015 were restricted to very small areas, whereas those in Sarpo Mira were similar to those in Solanum demissum, the main source of classical resistance genes. SW93-1015 can be characterized as a cpr (constitutive expressor of PR genes) genotype without spontaneous microscopic or macroscopic HR lesions. This is indicated by constitutive hydrogen peroxide (H₂O₂) production and PR1 (pathogenesis-related protein 1) secretion. SW93-1015 is one of the first plants identified as having classical protein-based induced defense expressed constitutively without any obvious metabolic costs or spontaneous cell death lesions.
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| 2. |
- Caspersen, Siri, et al.
(författare)
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Phosphorus efficiency of potato varieties differing in maturity type
- 2013
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The objective of the present work was to investigate the effect of phosphorus fertilization on yield and phosphorus uptake and to compare the phosphorus efficiency for six potato varieties. During 2011 and 2012, field experiments were conducted on soils containing low levels of available phosphorus. Phosphorus fertilizer was added in the amounts of 0, 30 and 60 kg phosphorus per ha. In 2011, soil heterogeneity was large and tuber yield was increased by phosphorus addition only as a mean over all varieties. In 2012, an improved tuber yield by phosphorus fertilization was observed for most varieties. The weight of the larger tuber fractions was generally increased by phosphorus fertilization. Phosphorus efficiency, calculated as tuber dry weight per unit of fertilizer phosphorus added, tended to be higher for late than for early or intermediate varieties. The results indicate that late varieties might be more suitable than earlier varieties for locations were the risk of nutrient losses is high.
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| 3. |
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| 4. |
- Dedicova, Beata, et al.
(författare)
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Effect of Cryopreservation on Growth of Different Elite Embryogenic Cell Lines of Norway Spruce (Picea Abies (L.) Karst.)
- 2011
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Ingår i: International Symposium on Cryopreservation in Horticultural Species. - : International Society for Horticultural Science. - 9789066054707 ; 908, s. 203-206
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Konferensbidrag (refereegranskat)abstract
- Callus from seven different elite embryogenic cell lines of Norway spruce originated from the controlled crossing conducted by Skogforsk (Forest Research Institute of Sweden) have been cryopreserved in liquid nitrogen using the slow freezing method with sorbitol (0.2 and 0.4 M) and DMSO (5% v/v) as cryoprotectants. Cooloing of samples was performed in a programmable freezer Cryo Med 7452. The cryovials were inserted at +4 degrees C and frozen at -0.3 degrees C/min to -16 degrees C. After 15 min at -16 degrees C, to avoid rapid cooling and crystal formation in the cells, the cryovials were further cooled to -35 degrees C at -0.3 degrees C/min. At the end of the freezing program the cryovials were transferred and stored in a CBS V1500 liquid nitrogen storage unit at -196 degrees C. After thawing and plating on proliferation medium, the recovered cells showed a short lag phase, after which they continued to grow. Lags in growth were also observed after the transfer to pre-maturation and maturation media. Somatic embryo maturation and plantlet regeneration occurred in all the tested embryogenic lines.
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| 5. |
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| 6. |
- Jansson, K. Ulrika, et al.
(författare)
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Length and classification of natural and created forest edges in boreal landscapes throughout northern Sweden
- 2011
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Ingår i: Forest Ecology and Management. - : Elsevier. - 0378-1127 .- 1872-7042. ; 262:3, s. 461-469
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Tidskriftsartikel (refereegranskat)abstract
- Forest edges have numerous implications for structure and function of forest ecosystems. Previous studies on edge quantity have used broad classifications. However, edge influence is driven by the contrast in vegetation structure between adjoining ecosystems, and thus we need detailed site-specific data to assess the role of edges in forests. We studied the variability of sharp edges in 28 boreal landscapes (4 km × 4 km) across an 830 km gradient throughout northern Sweden. Our objectives were: (1) to compare the length of natural and created edges, (2) to classify edges in detail by edge origin, maintenance and forest attributes, and (3) to examine relationships between length of edge and landscape variables. Data were collected using stereo-interpretation of high spatial resolution colour infrared aerial photographs, in combination with line intersect sampling and plots. The length of edge varied from 12 to 102 m ha−1 among landscapes, with an overall mean of 54 m ha−1. Created edges dominated most landscapes (mean 33 m ha−1) and had greater variability than natural edges (mean 21 m ha−1). Maintained edges (e.g. roads, agricultural land) were more abundant than regenerating edges caused by logging. Thirty percent of total edges adjoined narrow linear features. Seventy percent adjoined wider patches and showed high variability (35 classes). Overall, high-contrast edges towards mature forest dominated, i.e. ones that may experience strong edge influence. The amount of edge increased with percent of landscape affected by disturbance, and decreased with latitude and elevation. This study shows that edges are both abundant and highly variable in boreal forests and that forestry is the main driver behind edge creation. Detailed classification of edges based on site-specific forest and patch attributes may help to estimate edge influence at landscape level, and can guide experimental design for examining the impact of edges on structure and function of forest ecosystems.
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| 7. |
- Odilbekov, Firuz, et al.
(författare)
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Phenotyping early blight resistance in potato cultivars and breeding clones
- 2014
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Ingår i: Euphytica. - : Springer Science and Business Media LLC. - 0014-2336 .- 1573-5060. ; 197, s. 87-97
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Tidskriftsartikel (refereegranskat)abstract
- Thirty-two potato cultivars/clones were evaluated for resistance to early blight using different methods. The evaluations were performed under field and greenhouse conditions. In the field experiments, plants were evaluated for disease symptoms, and the relative area under the disease progress curve and percent defoliation were determined. In the greenhouse experiments, leaf lesion sizes were determined on either intact plants or detached leaves after drop inoculation with Alternaria solani. The effect of leaf position (lower, middle or upper part of the plant) on lesion size was investigated. There was no correlation between lesion sizes on lower leaves and upper leaves after inoculation. However, significant correlations between lesion sizes on lower and middle leaves and also between middle and upper leaves were found. Furthermore, we found significant correlation between the results of resistance studies in the field and in intact plant inoculation experiments in the greenhouse. In contrast, results from the detached-leaf experiment were not correlated with either greenhouse intact plant tests or field results. The results indicate that using detached-leaf assays for screening potato for early blight resistance is not accurate. We found significant differences in resistance to A. solani among cultivars/clones in both the field and in greenhouse experiments.
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