Comparative performance of some faba bean (Vicia faba) cultivars of contrasting plant types. 2. Growth and development in relation to yield

Abstract

Field experiments were conducted at Tel Hadya, Syria during 1985–1988 using faba bean (field bean) cultivars of three different plant types – independent vascular supply to each flower (IVS), determinate and indeterminate, sown at 22 and 44 plants/m2. The objective of the study was to determine whether yields had been stabilized and improved in the newly developed plant types. Both determinate and indeterminate cultivars continued producing nodes late into the season, the former by producing new branches and the latter on the existing branches. Late formation of branches in determinate lines was suppressed by sowing at a high seeding density of 44 plants/m2 in contrast to the usual density of 22 plants/m2. Indeterminate lines, e.g. ILB 1814, produced the highest leaf area index (LAI), intercepted the highest photosynthetically active radiation (PAR) and produced the highest total dry matter (DM). Among the determinate lines, FLIP 84–239F had a high LAI, intercepted a high PAR and produced a high DM. The IVS line, IVSFG–IVS 6, had a low LAI, intercepted a low PAR and attained a low DM. Sowing at a high density of 44 plants/m2 rather than 22 plants/m2 increased LAI and intercepted PAR, resulting in a higher DM production. Determinate lines partitioned proportionately more of the DM to the reproductive parts. Dry matter production was strongly correlated with cumulative intercepted PAR; with r ranging from 0·90–1·00 in both 1986/87 and 1987/88. The variation in the efficiency of conversion of intercepted PAR into DM amongst cultivars was low (1·309–2·017 g/MJ in 1986/87 and 1·191·2·057 g/MJ in 1987/88). ILB 1814 (an indeterminate cultivar) and FLIP 84–239F (a determinate cultivar) had higher light use efficiencies than the other cultivars. The range in cumulative intercepted PAR was, however, high; 224·8–417·8 MJ/m2 in 1986/87 and 118·4–369·1 MJ/m2 in 1987/88. Differences in DM at maturity were mainly due to differences in cumulative intercepted PAR. The relationship between DM at different growth stages and DM at maturity was strong; with the DM values at flowering showing the greatest correlations (r values of 0·93 in 1986/87 and 0·96 in 1987/88).