| 1. |
- Buntaran, Harimurti, et al.
(författare)
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A Cross-Validation of Statistical Models for Zoned-Based Prediction in Cultivar Testing
- 2019
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Ingår i: Crop Science. - : Wiley. - 0011-183X .- 1435-0653. ; 59, s. 1544-1553
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Tidskriftsartikel (refereegranskat)abstract
- The principal goals of a plant breeding program are to provide breeders with cultivar information for selection purposes and to provide farmers with high-yielding and stable cultivars. For that reason, multi-environment trials need to be done to predict future cultivar yield, and a robust statistical procedure is needed to provide reliable information on the tested cultivars. In Sweden, the statistical procedure follows the tradition of modeling cultivar effects as fixed. Moreover, the analysis is performed separately by zone and level of fungicide treatment, and so the factorial information regarding cultivar x zone x fungicide combinations is not explored. Thus, the question arose whether the statistical method could be improved to increase accuracy in zone-based cultivar prediction, since the cultivar recommendation is zone based. In this paper, the performance of empirical best linear unbiased estimation (E-BLUE) and empirical best linear unbiased prediction (E-BLUP) are compared using cross-validation for winter wheat (Triticum aestivum L.) and spring barley (Hordeum vulgare L.), in single-year and multiyear series of trials. Data were obtained from three agricultural zones of Sweden. Several linear mixed models were compared, and model performance was evaluated using the mean squared error of prediction criterion. The E-BLUP method outperformed the E-BLUE method in both crops and series. The prediction accuracy for zone-based yield was improved by using E-BLUP because the random-effects assumption for cultivar x zone interaction allows information to be borrowed across zones. We conclude that E-BLUP should replace the currently used E-BLUE approach to predict zone-based cultivar yield.
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| 4. |
- Guamán, Victor, et al.
(författare)
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Short time effects of biological and inter-row subsoiling on yield of potatoes grown on a loamy sand, and on soil penetration resistance, root growth and nitrogen uptake
- 2016
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Ingår i: European Journal of Agronomy. - : Elsevier BV. - 1161-0301 .- 1873-7331. ; 80, s. 55-65
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Tidskriftsartikel (refereegranskat)abstract
- Soil compaction, especially subsoil compaction, in agricultural fields has increased due to widespread use of heavy machines and intensification of vehicular traffic. Subsoil compaction changes the relative distribution of roots between soil layers and may restrict root development to the upper part of the soil profile, limiting water and mineral availability. This study investigated the direct effects of inter-row subsoiling, biological subsoiling and a combination of these two methods on soil penetration resistance, root length density, nitrogen uptake and yield. In field experiments with potatoes in 2013 and 2014, inter-row subsoiling (subsoiler) and biological subsoiling (preceding crops) were studied as two potential methods to reduce soil penetration resistance. Inter-row subsoiling was carried out post planting and the preceding crops were established one year, or in one case two years, prior to planting. Soil resistance was determined with a penetrometer three weeks after the potatoes were planted and root length density was measured after soil core sampling 2 months after emergence. Nitrogen uptake was determined in haulm (at haulm killing) and tubers (at harvest). Inter-row subsoiling had the greatest effect on soil penetration resistance, whereas biological subsoiling showed no effects. Root length density (RDL) in the combined treatment was higher than in the separate inter-row and biological subsoiling treatments and the control, whereas for the separate inter-row and biological subsoiling treatments, RLD was higher than in the control. Nitrogen uptake increased with inter-row subsoiling and was significantly higher than in the biological subsoiling and control treatments. However, in these experiments with a good supply of nutrients and water, no yield differences between any treatments were observed. (C) 2016 Elsevier B.V. All rights reserved.
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| 6. |
- Hagman, Jannie, et al.
(författare)
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Cultivation Practices and Potato Cultivars Suitable for Organic Potato Production
- 2009
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Ingår i: Potato Research. - : Springer Science and Business Media LLC. - 0014-3065 .- 1871-4528. ; 52, s. 319-330
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Tidskriftsartikel (refereegranskat)abstract
- To identify the most important agronomic measures and cultivar traits in Swedish organic potato production, multivariate analyses were performed on a set of data from a series of field trials carried out in Sweden during a 7-year period. The effects of soil parameters, cultivar, year and geographical location on potato characteristics were investigated. Soil parameters including fertility level had strong and significant effects on potato characteristics, explaining 53% of total variation. Variables related to the duration of haulm growth were other dominant factors in the variation. While P and K fertilization increased yields, N fertilization had little effect on yield and a negative effect on the time to emergence. The N requirement of potatoes ranges from 2.5 to 5.9 kg ha(-1) per ton of tuber yield and was met in these trials. The results implied the timing of N application is important for yield. It was concluded that the importance of P and K fertilization is underestimated in organic production, and that the most important cultivar trait in achieving acceptable yield is long-lasting foliage, which is a characteristic of cultivars resistant to Phytophthora infestans. Three of the cultivars tested (Lady Balfour, Cicero and Sarpo Mira) had a yield > 3.5 kg m(-2), which is high in Swedish organic production.
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| 7. |
- Hagman, Jannie
(författare)
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Different pre-sprouting methods for early tuber harvest in potato (Solanum tuberosum L.)
- 2012
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Ingår i: Acta Agriculturae Scandinavica, Section B - Soil and Plant Science. - : Informa UK Limited. - 0906-4710 .- 1651-1913. ; 62, s. 125-131
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Tidskriftsartikel (refereegranskat)abstract
- AbstractEarlier harvest of potatoes (Solanum tuberosum L.) can be achieved by different treatments of the seed tubers. This can be important, for example, in areas with a short growing season and in organic farming. In a pot experiment, different pre-sprouting methods were evaluated for four cultivars. The experiment consisted of (a) untreated seed tubers stored at 4 °C until planting, (b) traditional pre-sprouted tubers (P) and (c) pre-sprouted tubers with stimulation of adventitious root formation (PR). Pre-sprouted seed tubers have earlier and faster tuber formation, but often lower yield than non pre-sprouted tubers if there is no restriction of the growing season. The PR method developed here, where tubers were sprayed with water to stimulate adventitious root formation and give faster development and tuber initiation than conventional pre-sprouting, can be of value when the growing season is restricted or if early harvest is important. Initial emergence of the pre-sprouted potatoes was monitored in two pot experiments. Emergence was faster for the pre-sprouted treatments compared with the control, but there were no significant differences between the two pre-sprouting methods. At harvest, the pre-sprouted treatments gave higher yield than the control for all growing periods, methods and cultivars, although the differences were not significant for every combination. The cultivars Matilda, Cicero, Ovatio and Superb seemed to respond more positively in terms of yield to PR treatments than cv. Ditta. The new method for stimulating adventitious root formation developed here will substantially help growers to achieve earlier harvests.
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| 11. |
- Hagman, Jannie
(författare)
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Pre-sprouting as a Tool for Early Harvest in Organic Potato (Solanum tuberosum L.) Cultivation
- 2012
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Ingår i: Potato Research. - : Springer Science and Business Media LLC. - 0014-3065 .- 1871-4528. ; 55, s. 185-195
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Tidskriftsartikel (refereegranskat)abstract
- Earlier harvest of potatoes (Solanum tuberosum L.) can be achieved by different pretreatments of the seed tubers. In factorial field trials in 2008-2010, two different pre-sprouting methods were evaluated: conventional pre-sprouting of tubers and pre-sprouting of tubers with stimulation of adventitious root formation (PR). The results were compared with those for untreated seed tubers stored at 4 °C until planting (control). One variety was included in three trials, and two varieties were included in one trial. The new PR method was intended to give faster development and tuber initiation than conventional pre-sprouting, which can be of value when the growing season is restricted or when early harvest is important. Plant emergence, leaf necrosis (as a measure of maturity) and incidence of late blight were assessed during the growing season. After harvest, tuber fresh weight, size and density were assessed. It was found that pre-sprouting treatments gave on average 7 days earlier emergence compared with the control. Necrosis began earlier in pre-sprouted treatments in all cases except for the late variety Sarpo Mira. In 2008 and 2009 potato late blight struck late, after onset of senescence, but in 2010 it struck earlier and the pre-sprouted treatments proved more susceptible than the control. Total tuber yield was 7-24% higher on average in all pre-sprouted treatments in the different field trials. Tests on time of harvest showed that the advantage for the pre-sprouting treatments was maintained during the season, but the difference with the control decreased with time. When the different pre-sprouted treatments were compared, the new PR method proved to be not better than conventional pre-sprouting
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| 14. |
- Hagman, Jannie
(författare)
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Sortförsök i färskpotatis 2009
- 2009
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Ingår i: Skåneförsök 2009. - 9188668096 ; :76, s. 76-79
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Resultaten från färskpotatisförsöket sommaren 2009 visade tydliga skillnader i skördenivå mellan olika sorter och skördetidpunkter. Dessa resultat kan sedan utnyttjas för att bestämma vad som är en lämplig skördetidpunkt för respektive sort. Skördeutslaget för kvävegödsling (75 respektive 100 kg/ha) var litet utom för två sorter (Minerva och Vicking). Istället påverkade den höga kvävegivan kvaliteten och gav mer blötkokning för flera sorter
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| 15. |
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| 16. |
- Hagman, Jannie, et al.
(författare)
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Sortval i ekologisk odling 2015 : sortförsök 2010-2014 i höstvete, höstråg, rågvete, vårvete, vårkorn, havre, åkerböna, lupin, ärter och potatis
- 2015
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Rapport (övrigt vetenskapligt/konstnärligt)
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| 24. |
- Larsson, Staffan, et al.
(författare)
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Sortval i ekologisk odling 2010 : sortförsök 2000-2009 : höstvete, höstråg, rågvete, vårvete, vårkorn, havre, åkerböna, lupin, ärter, potatis
- 2010
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Rapporten innehåller resultat från den ekologiska sortprovningen med spannmål, trindsäd och potatis under perioden 2000-2009. Resultaten är kommenterade med hänsyn till områden, årsmån och andra tillväxtbetingelser. Jämförelser är gjorda med den konventionella sortprovningen
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| 25. |
- Larsson, Staffan, et al.
(författare)
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Sortval i ekologisk odling 2011 : sortförsök 2004-2010 : höstvete, höstråg, rågvete, vårvete, vårkorn, havre, åkerböna, lupin, ärter, potatis
- 2011
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Rapporten innehåller resultat från den ekologiska sortprovningen med spannmål, trindsäd och potatis under perioden 2004-2010. Resultaten är kommenterade med hänsyn till områden, årsmån och andra tillväxtbetingelser. Jämförelser är gjorda med den konventionella sortprovningen
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| 26. |
- Larsson, Staffan, et al.
(författare)
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Sortval i ekologisk odling 2012 : sortförsök 2007-2011
- 2012
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Rapporten innehåller resultat från den ekologiska sortprovningen med spannmål, trindsäd och potatis under perioden 2007-2011. Resultaten är kommenterade med hänsyn till geografiska områden, årsmån, och andra tillväxtbetingelser. Jämförelser är gjorda med den konventionella sortprovningen
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| 27. |
- Larsson, Staffan, et al.
(författare)
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Sortval i ekologisk odling 2013 : sortförsök 2008-2012
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Rapporten innehåller resultat från den ekologiska sortprovningen med spannmål, trindsäd och potatis under perioden 2008-2012. Resultaten är kommenterade med hänsyn till områden, årsmån och andra tillväxtbetingelser. Jämförelser är gjorda med den konventionella sortprovningen.
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