To determine whether vegetative response of genotypes to boron can mimic the genotypic yield responses to boron in the field.

• Boron (B) efficiency of oilseed rape (Brassica napus) and mustard (B. juncea) genotypes was determined on a low B soil at Mt. Compass, South Australia.
• B efficiency was observed in oilseed rape genotypes, Zhongyou 821, Dunkeld and Zheyou 2, and in mustard genotypes Pusa Bold and CSIRO 6.
• Genotypes grown in the field were also grown under glass-house conditions, in pots filled with pre-washed sand extracted from the Mt. Compass field site.
• Two B treatments, one B adequate (0.25 mg B /kg soil) and one B deficient (imposed by omission) were used to indicate whether vegetative response to B could predict final yield response and provide a more convenient selection criterion for identifying B-efficient germplasm .
• Vegetative response of 35 d old (D35) genotypes grown in pot culture closely reflected field response, indicating the expression of B efficiency traits in early growth, and its potential use in selection.