4 September 1998

Trial to end hybrid advantage

VARIETY association hybrid oilseed rapes – like Synergy – are to be grown separately in official trials to provide a more realistic yield comparison with other varieties.

A two-year HGCA-funded study confirms what critics of previous methods have long maintained, that sowing varietal association hybrids beside conventional types may give the hybrid an advantage because more pollen is available to help it set seed.

The change, starting with National List trials this autumn, will reflect more accurately what occurs in isolated farm fields with varieties sown at generally recommended seed rates, says NIABs John Ramsbottom.

But he strongly denies misleading growers over the relative performance of some hybrids. Ever since varietal associations arrived there has been a Recommended List footnote highlighting concern over reliability of their pollination in commercial crops, he notes. "

Perryfields Seeds Roy Harris welcomes the move to a more isolated trials. "It should provide a more realistic idea by being more akin to farmer practice."

Testing tall and short varieties together has also long been open to criticism, says Theo Labuda for Synergy supplier CPB Twyford. Even the latest trials changes do not meet all concerns, he notes. &#42