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ire ire ire Changes in seed composition to improve usages in food and feed may have resulted in modifications of seed physiological quality regarding germination and vigour. Improvement and prediction of seedling emergence and early seedling growth are important for the seed industry since field establishment significantly impacts the final yield of the crop. The European collaborative project Convigour involving eight partners has phenotyped a total of 735 oilseed rape accessions, including cultivars and breeders elite lines, to evaluate the genetic diversity for germination traits. A subset of 35 extreme genotypes was then trialed under field conditions over 9 locations and two years. The aim was to get tools in laboratory which can predict field emergence behavior, taking in account both genetic and environmental parts of the seed quality bases. All genotypes had a high standard germination except the second seedlot of genotype 14 (Fig. 3). Some genotypes were more vigourous than the other as their two seedlots resisted to a controlled deterioration test (Fig. 4). A seedlot effect was significant for 1/3 of the genotypes but genetic ranking remained the same whatever the seed production. 35 WOSR -12 cultivars - 23 breeder elite lines - 2 seedlots Laboratory experiments Automated germination time courses Controlled deterioration test GEVES - F49071 Beaucouzé, NPZ Innovation – D24363 Holtsee, INRA - IRHS 1345 - F49000 Angers, INRA - UMR IGEPP 1349 – F35650 Le Rheu, KWS SAAT – D37555 Einbeck, RAGT R2N – F12033 Rodez Winter oilseed rape (WOSR), the largest oilseed crop in Europe: stabilizing field establishment for a successful yield Seed germination and seed vigour testing in controlled conditions ire Controlled deterioration test of oilseed rape seeds predicts seedling emergence in a large range of field conditions. ©GEVES – May 2016 – Tous droits réservés This program has been funded by the French Research Agency and the Bundesministerium für Bildung und Forschung (2010-Plant KBBE-002-02) Most of the 35 WOSR genotypes were able to germinate fully in good conditions. More variability between genotypes was observed with the first seedlot used for 2012 field trials than for the second one produced in 2012 for the 2013 field trials (Fig.1). Germination speed depended on temperature but also on genotype (Fig,2). For example, the cultivar 7 get its optimal rate at 25°C (97%) and was sensitive to cooler temperatures (30% at 15°C and only 17% at 10°C). Figure 4: Normal germination after a controlled deterioration (CD) test for the two seedlots of the twelve cultivars produced in 2011 In France (Le Rheu) or in 2012 in Germany (Asendorf) Figure 1: Comparison of the germination time courses at 20°C for the two seedlots: means of the 35 cultivars ± SD Wagner M.H., Goertz S., Dürr C., Nesi N., Abbadi A., Demilly D., Leckband G., Breuer F., Dugué D., Ducournau S. Acknowledgments: Lydie Ledroit, Mélanie Durand, Pierre Lerebours, Hélène Navier ire Seed vigour evaluation in laboratory is helpful to predict field emergence when field conditions are unfavorable. In the present study, the ISTA controlled deterioration test was significantly correlated to the field establishment in contrasted conditions. Lab phenotyping can help breeding to adapt genotypes to the main environmental constraints for a crop including seed traits. ire Table 1: Field mean emergence of the 35 WOSR genotypes for the nine locations according to the year and the date of sowing,. Field emergence was measured two weeks after early sowings (ES) carried out between mid-August and mid- September or late sowings (LS) from the end of August till end of September depending on the location. y = 0,2098x + 51,519 R² = 0,6333 ** y = 0,3163x + 36,264 R² = 0,5272 ** 0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0 0 20 40 60 80 100 Field emergence after 2 weeks (%) Normal germination after controlled deterioration test (%) Late sowing 2012 field trial 2013 field trial 0 24 48 72 96 120 144 168 27 15 11 23 14 25 12 19 33 20 17 34 22 10 35 9 4 3 5 18 1 32 31 8 2 16 28 13 24 6 21 29 7 26 30 T50 (hours) T50 (h) 25°C T50 (h) 20°C T50 (h) 15°C T50 (h) 10°C • 10, 15, 20, 25°C • 24h at 45°C and 20% of seed moisture content Field emergence depends on agroclimatic conditions Figure 2: Germination speed (expressed by the time to reach 50% of germination T50) for the 35 cultivars (seedlot 2011/12) according to the temperature, Genotypes were ranked from the less sensitive to cold temperature to the more one. CD test on seed: a link between field and laboratory Figure 3: Normal germination after a standard germination (SG) test or a controlled deterioration (CD) test for the two seedlots of the 35 genotypes 2012 Early sowing (ES) Asendorf 09/05 Einbeck 08/24 Hohenlieth 08/23 Le Rheu 08/30 Leutewitz 08/15 Malchow 08/16 Prémesques 09/11 Seligenstadt 08/28 Vierville 09/05 ES Mean 2012 61.5 59.7 80.9 46.6 58.0 56.8 31.5 11.0 48.7 50.5 2012 Late sowing (LS) Asendorf 09/18 Einbeck 09/14 Hohenlieth 09/04 Le Rheu 09/28 Leutewitz 09/04 Malchow 08/29 Prémesques 09/28 Seligenstadt 09/18 Vierville 09/25 LS Mean 2012 75.3 70.1 83.1 66.5 61.4 34.1 67.1 71.6 54.8 64.9 2013 Early sowing (ES) Asendorf 09/02 Einbeck 08/30 Hohenlieth 08/20 Le Rheu 08/29 Leutewitz 08/23 Malchow 08/16 Prémesques 09/05 Seligenstadt 09/04 Vierville 09/12 ES Mean 2013 82.1 57.0 82.4 62.9 62.2 47.3 65.7 83.8 - 60.4 2013 Late sowing (LS) Asendorf 09/12 Einbeck 09/23 Hohenlieth 09/04 Le Rheu 09/25 Leutewitz 09/06 Malchow 09/05 Prémesques 09/20 Seligenstadt 09/24 Vierville 09/26 LS Mean 2013 76.7 42.0 86.8 54.0 79.8 69.3 73.4 43.6 25.6 61.6 Emergence ≥75% Emergence <50% Field emergence (FE) ranged between 11% (ES in Selingenstadt) to 83% (LS in Hohenlieth) in 2012 and from a very poor and heterogeneous emergence (ES in Vierville) to 87% (LS in Hohenlieth). It depended on both location and date of sowing (Tab.1). FE was better after a late sowing in 2012 for most of locations but it was not necessary the same in 2013. Extreme agroclimatic conditions were obtained in Malchow where FE was below 50% except in 2013 after a late sowing and in Hohenlieth which was the best place to be for WOSR as FE was near or above 80% each year whatever the date. Selingenstadt had the most contrasted FE between the two years : 11% in 2012 and 87% in 2013. Figure 5: Relationship between field emergence recorded with the number of plants emerged two weeks after a late sowing (mean of the 9 locations) and controlled deterioration results obtained in lab for the two seedlots of the 35 genotypes 0 20 40 60 80 100 0 6 12 18 24 30 36 42 48 54 60 66 72 Germination at 20°C (%) Imbibition time (hours) Mean extreme 2011/12 Mean extreme 2012/13 0 20 40 60 80 100 0 24 48 72 96 Germination (%) Imbibition time (hours) 20°C The CD test gave the best correlations between years and field locations (Fig. 5) even if the first year, germination speed was also an interesting trait to measure (data non shown). 0.0 20.0 40.0 60.0 80.0 100.0 1 2 3 4 5 6 7 8 9 10 11 12 Normal germination after CD test (%) 2011 seed production 2012 seed production 0.0 20.0 40.0 60.0 80.0 100.0 1-1 1-2 2-1 2-2 3-1 3-2 4-1 4-2 6-1 6-2 7-1 7-2 8-1 8-2 9-1 9-2 11-1 11-2 13-1 13-2 14-1 14-2 15-1 15-2 16-1 16-2 17-1 17-2 18-1 18-2 19-1 19-2 20-1 20-2 10-1 10-2 21-1 21-2 22-1 22-2 23-1 23-2 24-1 24-2 25-1 25-2 26-1 26-2 27-1 27-2 28-1 28-2 29-1 29-2 30-1 30-2 31-1 31-2 32-1 32-2 33-1 33-2 34-1 34-2 35-1 35-2 Normal seedlings (%) Genotype - seedlot Standard germination CD germination Contact: [email protected] CONVIGOUR Field trials 2012 and 2013 9 locations • 6 in Germany • 3 in France • Each with 2 sowing dates Late sowing Early sowing
