| 1. |
- Bergjord Olsen, A. K., et al.
(författare)
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Estimating winter survival of winter wheat by simulations of plant frost tolerance
- 2018
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Ingår i: Journal of Agronomy and Crop Science. - : Wiley. - 0931-2250 .- 1439-037X. ; 204:1, s. 62-73
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Tidskriftsartikel (refereegranskat)abstract
- Based on soil temperature, snow depth and the grown cultivar's maximum attainable level of frost tolerance (LT50c), the FROSTOL model simulates development of frost tolerance (LT50) and winter damage, thereby enabling risk calculations for winter wheat survival. To explore the accuracy of this model, four winter wheat cultivars were sown in a field experiment in Uppsala, Sweden in 2013 and 2014. The LT50 was determined by tests of frost tolerance in November, and the cultivars’ LT50c was estimated. Further, recorded winter survival from 20 winter wheat field variety trials in Sweden and Norway was collected from two winter seasons with substantial winter damages. FROSTOL simulations were run for selected cultivars at each location. According to percentage of winter damage, the cultivar survival was classified as “survived,” “intermediate” or “killed.” Mean correspondence between recorded and simulated class of winter survival was 75% and 37% for the locations in Sweden and Norway, respectively. Stress factors that were not accounted for in FROSTOL might explain the poorer accuracy at the Norwegian locations. The accuracy was poorest for cultivars with intermediate LT50c levels. When low temperature was the main cause of damage, as at the Swedish locations, the model accuracy was satisfying.
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| 2. |
- Mukamuhirwa, Alphonsine, et al.
(författare)
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Effect of intermittent drought on grain yield and quality of rice (Oryza sativa L.) grown in Rwanda
- 2020
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Ingår i: Journal of Agronomy and Crop Science. - : Wiley. - 0931-2250 .- 1439-037X. ; 206, s. 252-262
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Tidskriftsartikel (refereegranskat)abstract
- The climate change will contribute drought and temperature extremes to rice growing systems, especially when cultivated in equatorial regions. To evaluate opportunities to cultivate and breed drought-tolerant rice, seven rice cultivars were evaluated in Rwanda for recurring morphological drought scores, grain yield and components, and quality characteristics. The cultivation conditions, that is site and drought treatment, impacted morphological drought scores, growth and yield attributes, while cultivar affected quality attributes. Thus, site showed a higher impact on grain yield and components than drought and cultivar, with generally a reduced grain yield at the low-temperature site, as a result of low spikelet fertility. Morphological drought scores were generally increased by drought, while drought at the reproductive stage at the high-temperature site was negative for yield and its components. The cultivars "Intsindagirabigega" and "Jyambere" were adapted to high-temperature site conditions. The cultivar "Intsindagirabigega" had the highest amylose content, and "Mpembuke," the highest antioxidant capacity. Thus, climate change with increased temperature and drought extremes may increase rice productivity in cool areas, while especially drought at reproductive stage will be detrimental in low altitude areas with high temperature. Cultivar variation indicated opportunities for selection and breeding of climate change tolerant rice cultivars which should be of immediate priority.
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| 3. |
- Persson, Tomas, et al.
(författare)
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Estimation of Crown Temperature of Winter Wheat and the Effect on Simulation of Frost Tolerance
- 2017
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Ingår i: Journal of Agronomy and Crop Science. - : Wiley. - 0931-2250 .- 1439-037X. ; 203:2, s. 161-176
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Tidskriftsartikel (refereegranskat)abstract
- Accurate estimation of winter wheat frost kill in cold-temperate agricultural regions is limited by lack of data on soil temperature at wheat crown depth, which determines winter survival. We compared the ability of four models of differing complexity to predict observed soil temperature at 2 cm depth during two winter seasons (2013-14 and 2014-15) at Ultuna, Sweden, and at 1 cm depth at Ilseng and Ås, Norway. Predicted and observed soil temperature at 2 cm depth was then used in FROSTOL model simulations of the frost tolerance of winter wheat at Ultuna. Compared with the observed soil temperature at 2 cm depth, soil temperature was better predicted by detailed models than simpler models for both seasons at Ultuna. The LT50 (temperature at which 50 % of plants die) predictions from FROSTOL model simulations using input from the most detailed soil temperature model agreed better with LT50 FROSTOL outputs from observed soil temperature than what LT50 FROSTOL predictions using temperature from simpler models did. These results highlight the need for simpler temperature prediction tools to be further improved when used to evaluate winter wheat frost kill.
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| 4. |
- Andersson, Allan, et al.
(författare)
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Effects of Mild Temperature Stress on Grain Quality and Root and Straw Nitrogen Concentration in Malting Barley Cultivars
- 2011
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Ingår i: Journal of Agronomy and Crop Science. - 0931-2250. ; 197, s. 466-476
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Tidskriftsartikel (refereegranskat)abstract
- It is a challenge to obtain the appropriate protein concentration in cereals for the intended end-use. This study examined ambient temperature effects on two spring malting barley cultivars (Henley and Tipple) grown in soil or in solution culture with controlled nitrogen supply in daylight chambers with low temperature (day 18 degrees C, night 12 degrees C), and high temperature (23 degrees C/17 degrees C) to/after anthesis. In soil-grown plants, high temperature to anthesis resulted in higher grain nitrogen amount (GNA), grain nitrogen concentration (GNC) and straw nitrogen concentration (SNC). In plants grown in solution, high temperature to anthesis resulted in lower GNA and higher GNC. A temperature rise of 1 degrees C during the growing period in solution cultivation increased GNC, root nitrogen concentration (RNC) and SNC, by 1.20, 1.35 and 0.33 mg g(-1), respectively. In solution culture, GNC was positively correlated with RNC and SNC (P < 0.01). Cv. Henley had higher GNC but lower SNC than cv. Tipple. Cv. Henley was more stable in grain size and cv. Tipple in GNC. The results showed that temperature has a direct effect on GNC. Accounting for temperature fluctuations up to the latest possible nitrogen fertilisation occasion can therefore help when deciding appropriate nitrogen supply for intended end-use.
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| 5. |
- Bargaz, Adnane
(författare)
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Improved Salinity Tolerance by Phosphorus Fertilizer in Two Phaseolus vulgaris Recombinant Inbred Lines Contrasting in Their P-Efficiency
- 2016
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Ingår i: Journal of Agronomy and Crop Science. - : Wiley. - 0931-2250. ; 202, s. 497-507
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Tidskriftsartikel (refereegranskat)abstract
- Legumes' sensitivity to salt is exacerbated under growth conditions requiring nitrogen fixation by the plant. Phosphorus (P) deficiency is widespread in legumes, especially common bean (Phaseolus vulgaris L). To examine the performance of P. vulgaris under salt stress conditions, a field experiment was conducted using two recombinants inbred lines (RILs) 115 (P-deficiency tolerant) and 147 (P-deficiency susceptible), grown under different salinity levels (L) (1.56, 4.78, and 8.83 dS m(-1) as LI, L2, and L3, respectively) and supplied with four P rates (0, 30, 60, and 90 kg ha(-1) P as P0, P30, P60, and P90, respectively) in order to assess the impact of P on salt tolerance. Results indicate that growing both RILs at P60 or P90 under all salinity levels (especially L1) significantly increased total chlorophyll, carotenoids, total soluble sugars, total free amino acids, and proline. Increasing P supply up to P60 under all salinity levels significantly induced higher accumulation of P, K+, Ca2+ and Mg2+ leaves in both RILs. Based on quadratic response over all locations, the maximum seed yield of 1.465 t ha(-1) could be obtained at application of P 81.0 kg ha-1 in RIL115, while seed yield of 1.275 t ha(-1) could be obtained with P rate of 78.3 kg ha(-1) in RIL147. RIL115 exhibited more salt-tolerance with positive consequence on plant biomass and grain yield stability. Improved salt tolerance through adequate P fertilization is likely a promising strategy to improve P. vulgaris salinity tolerance and thus productivity, a response that seems to be P-rate dependent.
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