Genotypic variation in tolerance to boron toxicity in 70 durum wheat genotypes.

摘要

A greenhouse experiment was carried out to study the variation among 70 durum wheat (Triticum durum) cultivars in their tolerance of B toxicity in soil. Plants were grown on soil containing 12 mg extractable B kg-1 soil treated with 0 (-B) or 25 mg kg-1 soil (B+). At 30 days after sowing, shoots were analysed for dry matter production and shoot B concentration B. A large genotypic variation in terms of tolerance of B toxicity was observed based on the severity of leaf symptoms and decreases in dry matter production. The growth of Sabil-1, Stn "S", Aconhi-89 and Wadelmez-2 was not affected, and growth in these cultivars tended to increase under B toxicity. Dry matter production in the other genotypes was markedly reduced by B application, particularly in Lagost-3, Dicle-74, Brachoua/134 x S-61 and Gerbrach. In Brachoua/134 x S-61 and Gerbrach, B application reduced the dry matter weight by 2-fold. The relationship between shoot B concentration and relative decrease in shoot dry weight due to B toxicity was not significant. The most B-sensitive genotypes had generally much lower amount of B in shoots than the genotypes showing greater tolerance of B toxicity. The results indicated that the B exclusion mechanism is not involved in the differential expression of B tolerance in the 70 durum wheat genotypes..