Biology of Brassica napus. KWS oilseed rape breeding strategies under arid climate conditions

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1 KWS oilseed rape breeding strategies under arid climate conditions Ralf Reinhardt MA-OCC KWS SAAT SE Biology of Brassica napus amphidiploid species number of chromosomes: (2n) 38 Two pairs of chromosomes: AA derived from Turnip rape(b. rapa) CC derived from cabbage (B. oleracea) Resynthesize of B. napus is an important tool for the broadening of genetic diversity no wild species known Self-pollinating species with a high occuence of cross-pollination under natural conditions breed as a self-pollinator

2 Breeding efforts of oilseed rape Compared to other arable crops oilseed rape has a very short history in breeding, cultivation and use First efforts to increase the use of rapeseed oil was to reduce erucic acids Second step was to decrease glucosinolate content in pressed oilseed cake First OSR variety with low erucic acid content in Europe First double low varieties in Europe Breeding efforts of oilseed rape To increase rapeseed yield first composite hybrids were introduced in 1994 Composite hybrids are pollen sterile hybrids mixed with open-pollinating varieties Limited success in Europe as high environmental risk First OSR variety with low erucic acid content in Europe First composite hybrid in Europe First double low varieties in Europe

3 Breeding efforts of oilseed rape The first fully restored WOSR hybrids in Europe were based on a Nuclear genetic system. Practically there were no public information available. Restored hybrid have lower environmental risk as composite hybrids High effort to breed and multiply sterile mother lines First OSR variety with low erucic acid content in Europe First composite hybrid in Europe First double low varieties in Europe First fully restored hybrid in Europe Breeding efforts of oilseed rape First OGURA-Hybrids registered in Europe Today 80% of the European WOSR is covered with hybrids Out of this 65-70% are grown with OGURA-hybrids Very fast breeding progress can be achieved by using the OGURA-system First OSR variety with low Erucic acid content in Europe First composite hybrid in Europe First OGURA- Hybrid in Europe First double low varieties in Europe First fully restored hybrid in Europe

4 OGURA Breeding Sterile mother lines OGURA-cytoplasm will support male sterility X High performing KWS genetic used as maintainer F1 X OGURA-plasm Napus plasm without restorer gene RR homozygote restorer gene BC1 = 1. backcross BC5 = ms-line 98,5% KWS-genetic X Hybrid system based on cytoplasmic male sterility (OGURA-CMS) Relatively easy to use and fast backcrossing system to develop new mother lines. Fast breeding progress Stable sterility system in all climate conditions OGURA Breeding Hybrid development Father side Sterile ms-line Mother side maintainer line X X RR F1-Hybrid Father lines need to have a homozygote restorer gene to restore the male fertility of the hybrid High efficiency to develop new father lines Fast breeding progress on both parents Fertility of hybrids is stable in all environmental conditions RR OGURA-plasm Napus plasm without restorer gene RR homozygote restorer gene

5 KWS breeding strategy Main importance for winter oilseed rape is clearly in Europe Inside the large growing region there is less differentiation of genotypes towards regions like e.g. earliness of ripening. Some varieties shows good results from Scotland to eastern Poland or even south Romania. However, breeding is difficult caused by large interactions between genotypes, years and locations Conclusions for KWS Broad testing of all material in the whole European growing area Observation plots (lodging, fungal diseases) mainly in hot spots of Europe (France, Germany, Scotland) Yield testing in the whole growing area Only one gene pool in relation to climatic conditions (but of course two heterotic gene pools for hybrid development) Important selection criteria Seed yield always on highest priority, just in special cases like disease tolerance or herbicide tolerance yield is not the priority Oil content very important to increase oil yield Tendency to lodging important, and could really be improved in recent years Winter hardiness important (Poland, Baltic Countries, South East Europe) Plant length medium important

6 Important diseases Phoma/Cancer/Blackleg (Leptosphaeria maculans) good differentiation of the breeding material, polygenic inheritance and some very effective monogenic dominant resistance gene ( e.g. rlm7) very important Light Leaf Spot (Pyrenopeziza brassicae ) good differentiation of the breeding material, polygenic inheritance important Clubroot (Plasmodiophora brassicae) monogenetic inheritance Sclerotinia (S. sclerotiorum) Only small differentiation in the European breeding material Verticillium (V. longisporum) Only limited knowledge of variation in the breeding material Special criteria for arid climate conditions Maturity and equality of ripening Early maturity will increase the water use efficiency Healthy plants are necessary and really improve yield in western European conditions. Under arid conditions green stems and leaves at technical maturity can increase transpiration without any yield effect. Shatter resistance High temperature at harvest time increase the risk of pre harvest losses due to open siliques For arid conditions KWS is improving the shatter resistance Increase the Harvest index of oilseed rape to increase water use efficiency Two ways are in focus of KWS to increase Harvest index. The one is to decrease sowing rates by a precise seed placement. The other is to breed semi-dwarf hybrids.

7 Breeding target disease tolerance vs. equal ripening Stem cancer (Phoma lingam) Both breeding targets are partly contrary It is a question of product management to choose the best hybrids for different climate conditions Shatter resistance laboratory trials ,5 force to open the pods 3,0 2,5 2,0 1,5 1,0 0,5 Ext. Check Raptor 1 Ext. TREFFER Check 2 HYBRIROCK MARCOPOLOS FRODO KWS FACTOR KWS GORDON KWS German agricultural laboratory is offering this kind of trial (LUFA Rostock) KWS tested it s own portfolio regarding shatter resistance of the siliques For each hybrid 100 siliques were analyzed about the force necessary to open the siliques Hybrids with different genetically background showed clear differentiation Hybride

8 Shatter resistance laboratory trials 2014 Repeating the pod shattering trial in locations 3 in North and 3 in South of Europe 7 Hybrids External check 1 External check 2 HYBRIROCK FRODO KWS GORDON KWS FACTOR KWS ALVARO KWS Shatter resistance laboratory trials ,5 3 2,5 2 1,5 1 0,5 0 Force (N) Comparable results to 2013 Slightly different ranking between the two year tested hybrid but again a clear differentiation between different genetically background

9 Shatter resistance screening trials of breeding material Increase of Harvest index Sowing rate (seeds/m²) Survived over winter (plants/m²) Siliques per Plant Kernels per silique TKW (g) Yield at 91%DM (dt/ha) AVR LSD 5% significant significant not sig. not sig. not sig. Source: Bischoff, 2004; German governmental research institute In that trial no Harvest index was measured but it seems to be obvious that total biomass will be less at low plant density. Plants fully compensated the missing plants by forming side branches with additional siliques No effect on thousand kernel weight or on yield.

10 Increase of Harvest index KWS trials were caied out to understand interaction of genetic background and sowing rate in different climate conditions. Three dry locations in Hungary were compared to three wet locations in northern Germany and Poland. Sowing range varied in between 20, 50 and 80 kernels per square meter An old open pollinated variety was compared to an older hybrid and a new hybrid Harvest index could be increased by reducing the sowing rate The old OP ALASKA had a negative yield effect by reducing sowing rate on a certain level. New hybrid HYBRIROCK did not respond with yield losses Increase of Harvest index wet dry AVR Harvest Index sowing rate (kernels/m²) Seed Yield (dt/ha) sowing rate (kernels/m²) AVR AVR ALASKA OP 32,2 31,8 30,3 31,4 43,5 45,5 44,8 44,6 TRIANGLE H 30,9 32,5 29,2 30,9 42,6 46,5 43,8 44,3 HYBRIROCK H 35,9 35,2 33,0 34,7 50,2 51,0 49,5 50,2 AVR 33,0 33,2 30,8 32,3 45,4 47,7 46,0 46,4 ALASKA OP 34,3 33,2 31,4 33,0 38,0 44,4 44,6 42,3 TRIANGLE H 34,8 34,5 30,8 33,4 43,7 46,4 44,2 44,8 HYBRIROCK H 35,8 34,2 32,5 34,2 48,3 48,0 48,4 48,2 AVR 35,0 34,0 31,6 33,5 43,3 46,3 45,7 45,1 ALASKA OP 33,3 32,5 30,8 32,2 40,7 44,9 44,7 43,4 TRIANGLE H 32,8 33,5 30,0 32,1 43,1 46,5 44,0 44,5 HYBRIROCK H 35,8 34,7 32,8 34,4 49,3 49,5 49,0 49,2 AVR 34,0 33,6 31,2 32,9 44,4 47,0 45,9 45,7 To select the best adapted hybrids, sowing density need further be reduced in yield trials in arid climate conditions.

11 Thank you for your attention