Abstract
SUMMARY: A study of the physiological responses of a hybrid between a North European population and a colchicine‐induced autotetraploid of a Portuguese population of Dactylis glomerata subspecies lusitanica showed an intermediate response of the hybrid for many characters. However, the hybrid resembled one or other of the parents in the more favourable expression of certain characters in controlled environments at 20°C, 16 h photoperiod and 8 °C, 8 h photoperiod. Rate of dry‐matter production of the hybrid did not differ significantly from that of the northern parent at 20 °C, 16 h and that of the Portuguese parent at 8 °C, 8 h. Leaf growth of the hybrid at 8 °C, 8 h was greater than that of the northern parent and together with the high percentage survival in a freezing test may indicate a role for similar hybrids in the development of potential varieties with improved seasonal distribution of dry‐matter production.