Designing Crops for Variable Environments Prof. Martin S Wolfe Elm - PowerPoint PPT Presentation

I O R Designing Crops for Variable Environments Prof. Martin S Wolfe Elm Farm Research Centre Wakelyns Agroforestry

I O R What is special about conventional systems? yield t/ha HGCA conventional wheat trials over 5 years 11 Fungicide Treated 10.5 Fungicide Untreated 10 9.5 9 8.5 8 7.5 7 6.5 6 Xi19 Solstice Hereward Variety

I O R Conventional systems High yields are produced by: a) High inputs to try to eliminate any limits to production b) Varieties bred to respond to such high inputs: high HI But the costs are high…..and increasing

I O R Are organic systems different? Small Plot Replicated Trials in 2004 Mean Variety Grain Yield, LSD = 0.66 5 4.5 4.24 3.96 t/ha 3.78 4 3.5 3.5 3 Small Plot Replicated Trials in 2003 Xi19 Solstice Mix Hereward Mean Variety Grain Yield Variety 5 4.45 4.5 4.11 t/ha 4 3.23 3.5 3 Xi19 Solstice Hereward Variety

I O R Organic varieties? Comparisons of winter wheat trials indicates three classes of variety: A) Good under conventional AND organic conditions (Claire, Deben) B) Good under conventional BUT LESS SO under organic conditions (Solstice, Xi19) C) Poor under conventional BUT GOOD under organic conditions (Hereward, Spark)

I O R • So, wheat varieties respond differently to organic conditions generally, and to the variation in organic conditions • How are such responses expressed? • And on what scale?

I O R DEFRA OF0330 Participatory research: a simple wheat trial on 15 organic farms There was much variation in yield, 7.0 due to: Mean Grain Yield (t/ha), LSD = 0.62 5.8 5.8 6.0 5.3 •Variable fertility 4.9 5.0 4.7 4.3 4.0 3.8 • Rotational 3.7 4.0 t/ha 3.5 3.0 position 3.0 2.5 2.4 2.3 2.3 2.0 • Variable weed loading 1.0 0.0 • Other interacting A B C D E F G H I J K L M N O Site factors

I O R ‘Tall’ and ‘Short’ sites (OF0330) Straw height versus grain yield correlation (N.S.) 90 80 70 Straw height (cm) 60 50 40 30 20 10 0 0.0 2.0 4.0 6.0 8.0 10.0 Yield (t/ha)

I O R Wheat yields at 7 ‘Tall’ sites compared with 8 ‘Short’ sites Grain yields for all varieties Tall sites 5 Grain yield (t/ha at 15% moisture) Short sites 4.4 4.4 4.5 4.2 3.9 3.9 4 3.6 3.5 3.4 3.5 3 2.5 2 1.5 1 0.5 0 Hereward Mixture Solstice Xi19 Variety

I O R Straw lengths and numbers of heads at 7 ‘Tall’ and 8 ‘Short’ sites Straw length for varieties at tall and short sites Tall sites Short sites 80 72.2 68.4 67.9 70 63.5 Mean straw length (cm) 60 50 35.6 40 34.2 33.4 32.3 30 20 10 0 Number of heads per sqm for varieties at tall Hereward Mixture Solstice Xi19 and short sites Variety Tall sites Short sites 757 748 800 Mean head density (heads/m2) 678 700 586 600 475 500 427 411 366 400 300 200 100 0 Hereward Mixture Solstice Xi19 Variety

I O R Cumulative straw length and the correlation with weed cover Total straw length per square metre for varieties at tall and short sites Tall sites Short sites 400 340 Total straw length (m) 350 305 284 300 257 241 231 219 250 205 200 150 100 50 0 Hereward Mixture Solstice Xi19 Correlations of weed cover with straw length per Variety sq m. Tall sites 0.4 Short sites Hereward 0.2 Xi19 0 -0.2 -0.4 Mixture Solstice -0.6 -0.8 Hereward Mixture Xi19 Solstice -1

I O R Varieties clustered by tall/short plant and low/high yield sites 90 Xi, So, Mix, He 80 Mix, So, Xi, He 70 Straw height (cm) 60 50 40 30 Xi, Mix, So, He 20 Xi, So, He, Mix 10 0 2 2.5 3 3.5 4 4.5 5 5.5 6 Yield (t/ha)

I O R Varieties clustered by yield (t/ha) and numbers of heads per sq m. No. heads vs Yield 900 H/S 800 L/S 700 No. heads per sq m 600 500 400 H/T 300 L/T 200 100 0 0 1 2 3 4 5 6 Yield t/ha

I O R Dynamics of “Harvest Index” for variety means at the four site clusters Yield vs CSL 60 Cumulative straw length T/H 50 40 m/m2 T/L 30 20 S/L S/H 10 0 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 6.00 Yield t/ha Length per sq Length per sq “Harvest m Short sites m Tall sites Index” Low Yield 1.39 1.45 High Yield 2.33 1.06

I O R What happened ? • Distribution of resources among numbers of grains, numbers of heads and length of straw was highly variable among sites • BUT all varieties followed a similar pattern of variation • Hereward performed better than Xi19: more plastic genotype • Environmental effects (4 t/ha) were much greater than genotypic (0.5 t/ha)

I O R How should we deal with such variation in organic systems? • By improving fertility amount and dynamics • By breeding/choosing appropriate varieties with plastic response • By using heterogeneous crops with built in adaptability such as variety mixtures, species mixtures and crop populations

I O R High, stable yield from 3-variety wheat mixture HeMaSh mixture '00 4.07; '01 2.53; '02 3.99; '03 3.47 t/ha 140.0 104 110 101 95 120.0 % of component means 100.0 80.0 60.0 40.0 20.0 0.0 Shamrock Malacca Hereward HMS

I O R DEFRA AR 0914 Composite Cross: Selection of Parent Lines High Quality Potential High Yield Potential 1 Bezostaya 1 Bezostaya 2 Cadenza 2 Buchan 3 Hereward 3 Claire 4 Maris Widgeon 4 Deben 5 Mercia 5 High Tiller Line 6 Monopol 6 Norman 7 Pastiche 7 Option 8 Renan 8 Tanker 9 Renesansa 9 Wembley 10 Soissons 11 Spark Plus 4 male sterile lines 12 Thatcher

I O R Composite crosses: plant populations under conventional and organic conditions Change in plant numbers per sq. m. Conventional 250 Organic 200 150 100 50 0 Early Final

I O R Yield development of composite cross populations under conventional and organic conditions Composite Cross F3 under conventional and organic conditions 800 Conventional 700 Organic 600 500 400 300 200 100 0 No. plts E No. plts L Ears/sqm Yld g/sqm

I O R Performance of Composite Cross population in first field season YQ Composite Cross population (F3) compared with physical mixture 800 Mix 700 Comp CompMS 600 500 400 300 200 100 0 Convent Organic Convent Organic Convent Organic Early plant nos. Ears/sqm Yield g/sqm

I O R Conclusions… • Organic systems are highly variable: they demand fundamentally different varieties from conventional systems • Improvements in the dynamics of soil fertility are needed • Some conventionally bred varieties can be relatively effective under organic conditions

I O R Conclusions… • Inter-cropping with legumes needs further development • Variety mixtures can be helpful – if the right components are available • Composite cross populations offer potentials for adaptable crops and for rapid production of adapted genotypes