Tomato blossom end rot (BER) in CIPS

• Genotype: The factor having the greatest incidence (%BER) and the greatest range was genotype. The greatest %BER occurred with tomato cultivars with homozygous, uu, geno-type with 'uniform' pigmented fruit (24% BER); the least incidence of BER occurred with the UU, 'green shouldered', genotypes (5% BER).
• Salinity: %BER of susceptible cultivars (uu) decreased with increased salinity (mg/l NaCl) in the irrigation water in CIPS decreasing from 17.7% BER at 0 mg/l NaCl to 5.4% BER at 10,000 mg/l NaCl.
• Nitrogen Form: Providing half of the nitrogen equivalents as ammonium resulted in 16% BER incidence on susceptible cultivars (uu cultivars) compared with 11% BER on nitrate-fertilized tomatoes.

'Santium' (left) is an example of a 'green shouldered' (U-genotype) tomato cultivar that is not susceptible to BER.