Heterosis and inheritance of drought tolerance in faba bean, Vicia faba L.

Twelve parental lines of faba beans and 27 F-1 hybrids derived from them we re field-tested under a dry and a well-watered treatment, at two German loc ations (Gottingen, Hohenheim) in two years (1995, 1996). Drought was artifi cially induced using rain shelters from anthesis until maturity. Data were collected on yield under dry (Yd) and well-watered (Yw) conditions. Drought tolerance was assessed as Yd/Yw. The midparent heterosis was significant f or Yd and Yw, but not for Yd/Yw. Relative heterosis for Yd (52.0%) was grea ter than for Yw (39.3%). Parental heritability was greater for Yw (0.86) th an for Yd (0.61). However, it was similar for both traits in F-1 hybrids (0 .65 and 0.66). Principal component analysis showed that F-1 hybrids exhibit ed the same pattern of adaptation as their parents. The heritability of dro ught tolerance was 0.48 in F-1 hybrids and 0.70 in parents. Attention shoul d be paid to its negative correlation with yield. Several hybrids combined high tolerance, a favourable pattern of adaptation and appropriate performa nce.