Mass selection for crown height in sugar beets (Beta vulgaris L.). 2. Divergent selection in tetraploids

Summary Five cycles of mass selection for high and low crown height in one tetraploid sugar beet population and four cycles of mass selection for high crown height in another tetraploid population gave average gains of 10–15% per cycle. Realised heritabilities were about 0.3. This progress was obtained because special attention was paid to practical aspects for improving the mass selection method.The responses to selection were measured in successive years and evaluated in 1979 (cycles 1–4) and in 1980 (cycle 5). The correlation coefficients between the data obtained in successive years and those from the evaluation trials were very high (r=0.99).In tetraploids. mass selection for crown height can be applied successfully.