Genetic diversity of oilseed Brassica napus inbred lines based on sequence-related amplified polymorphism and its relation to hybrid performance.

Significant heterosis for seed yield in oilseed rape has created interest in the development of hybrid cultivars. The DNA-based marker protocol, sequence-related amplified polymorphism (SRAP)was used to determine genetic diversity among oilseed rape maintainer and restorer lines. This measure was used in an attempt to establish an association between genetic distance and heterosis in hybrids for various agronomic traits. A total of 118 polymorphic loci were generated by 18 SRAP primer combinations. Based on the polymorphism generated by the markers, calculated similarity index values ranged from 0.46 to 0.97. Cluster analysis grouped 10 maintainer and 12 restorer lines into three groups, with the exception of two maintainer lines, PM5 and PM9, which fell outside these groups. The grouping of the lines was largely in agreement with the available pedigree data on their origin and agronomic performance. Analysis of variance among inbred lines and their resulting F1 hybrids over two locations revealed significant differences for plant height, days to maturity and seed yield, but not for oil content. Substantial mid-parent heterosis was observed only for seed yield, and ranged from 26