Patterns of genetic diversity and relationships between regional groups and populations of Italian landrace cauliflower and broccoli (Brassica oleracea L var botrytis L and var italica Plenck)

Italy is widely regarded as the centre of diversity for cultivated Brassica oleracea L. var. botrytis and italica (cauliflower and broccoli) and is therefore very important with regards to genetic information in these crops. As a result of the EC collection programme 0890 in 1983/84 (van der Meer et al, 1984), the hypothesis of distinct regional groups was formulated. A PhD project was initiated to test this hypothesis and to determine at what levels the variation is partitioned. To achieve this it was necessary to compare the variation within and between populations for each regional type. Morphological characters were used to assess variation in fifty two accessions from Italy, one each from Australia, India, and Portugal, a F1 hybrid, a doubled haploid cauliflower line and an inbred broccoli line. Forty nine leaf and head characters were analysed from field acid polytunnel experiments. Analysis of variance was used to identify characters with significant contributions to the variance. Cluster, discriminant, and canonical variate analyses were used to assess the relationships between populations and regional groupings. Results from the analyses appear to show that within this study are distinct. The morphological variation present is significantly different between regional types and is significantly greater than the variation between populations within the regional groups.