Care required when choosing a variety
BE wary of relying on untreated NIAB trials rankings to choose the best wheat varieties to grow organically, warned EFRCs James Welsh.
Two years work with replicated plots on six organic farms suggests there is even a reversal of performance in some varieties (see table).
Variety mixtures, however, do seem to offer the chance to stabilise yields without jeopardising quality, said Dr Welsh.
Malacca on its own performed particularly poorly as an organic wheat last year, yielding about 30% less than Hereward and Shamrock. But a mix of all three did only slightly less well than those two on their own and even outyielded Shamrock alone in 2000.
The mix also had less Septoria tritici than the predicted average.
"We have only two years data, but the trend is that varietal mixtures can help buffer the crop against environmental variations that occur between sites and seasons."
Overall, the effects on quality, in terms of specific weight, Hagberg and protein levels, were mainly positive, he added. Similar effects were also seen in winter oats, triticale and spring wheat.
But with millers still preferring single varieties, marketing mixes poses potential problems, said Dr Welsh.
"I will happily supply the seed ingredients but not the mixtures," added OSPs Roger Wyarrt. "The logistics are horrendous."
Winter wheat yield rankings (2001)
NIAB untreated NIAB organic EFRC organic
1 Deben 1 Hereward 1 Claire
2 Option 2 Petrus 2= Spark
3 Solstice 3 Shamrock 2= Shamrock
4= Napier 4 Exsept 2= Aardvark
4= Claire 5 Claire 3 Hereward
4= Shamrock 6 Aardvark 4 Deben
6= Malacca 7 Malacca 5 Malacca
6= Hereward 8 Deben