Fig. 4.

Relationships between (a) HI and fertile tillering, (b) HI and plant height, and (c) fertile tillering and number of stems/m², of 16 bread wheat genotypes widely grown in Spain during the 20th century. Each point represents the mean value of one genotype across four experiments. Breeding periods are identified with triangles for local landraces, diamonds for initial cultivars, squares for intermediate cultivars and circles for modern cultivars. Equations and R² values are only presented for significant relationships at P<0·05 (d.f.: 15).