To assess the influence of plant population and cultivar on crop structure, dry matter production and grain yield in two identical faba beans trials under surface irrigation.

• The grain yield of Fiesta VF was 5% higher than PBA Amberley under overhead irrigation.
• Seed rate had a significant impact on grain yield with yield maximised at the highest plant populations, although there was little yield advantage above approximately 25-30 plants/m2 with either cultivar.
• If plant population fell to 12 plants/m2 the yield reduction was approximately 1.2 with Fiesta VF and 1.8t/ha with PBA Amberley.
• There were no significant differences in harvest dry matter due to plant population with all cultivars and populations achieving approximately 12-14t/ha.
• There was no significant difference in pod number due to plant population with all populations including the thinnest producing approximately 500 pods/m2.
• Significantly lower plant populations being lower yielding due to less beans per pod or smaller thousand seed weight.
• Increasing plant populations significantly increased stem number per m2 and height to first pod with stem number over 65 stems/m2 being associated with the highest yields.
• Plant population had no significant on dry matter production at harvest.