Hybrid Cultivars

Hybrid oilseed rape varieties currently produce the highest yield in the UK, because they exhibit the characteristic known as 'hybrid vigour', thus grow more vigorously and subsequently have a greater yield potential. They also have more branches, with more pods and larger seed. The area of hybrid winter oilseed rape grown in the UK increased six-fold between 1995 and 1997, to around 60,000 hectares.

Hybrid oilseed varieties are created by crossing pure parental lines to produce an 'F1' hybrid and hybrid seed is produced by preventing self-fertilisation of the maternal parent. This is generally achieved by introducing one of several forms of male sterility to prevent pollen production in the female parent. The resulting male sterile is then crossed with a male, pollen producing parent to produce the hybrid seed.

There are two types of commercially available hybrid oilseed rape varieties:

Varietal association hybrids:
Composed of a mixture of male sterile hybrid plants which do not produce pollen and a pollinator (plants of one or more varieties whose function is to supply pollen). The first to achieve 'Recommended List' status in the UK was 'Synergy' (winter), and is made up of 80% male sterile hybrids and 20% pollinators (optimum ratio for pollination and yield objectives).
Restored hybrids:
All plants fully fertile and capable of producing pollen and setting seed without cross pollination. 'Pronto' and 'Artus' were the first hybrid restored winter varieties to be marketed in the UK.

The extra yield potential of hybrids can be exploited with only minor modifications to crop farming, so the returns from hybrid crops are higher than those from inbred cultivars. The new hybrid varieties mentioned all produce significant yield advantages of up to 10% over the conventional and widely grown variety, 'Apex'.