เปรียบเทียบการตอบสนองต่อการขาดธาตุโบรอนในข้าวบาร์เลย์และข้าวสาลี

บทคัดย่อ

To determine if boron (B) deficiency, commonly reported to depress grain set in wheat, has the same effect in barley, two experiments compared three wheat and three barley genotypes at various B levels in sand culture. Plants were grown with varied levels of added B, from 0 to 10 μM. Without added B, the genotypes ranged in Grain Set Index (GSI) from 0 to 93% for wheat and 0 to 67% for barley. Boron concentration of the ear and flag leaf at boot stage in wheat and barley correlated (r = 0.8 – 0.9, p <0.01) with the effect of B on GSI. Grain set was the only response to low B, also measurable in decreased number of grains ear^-1 and grains spikelet^-1, in wheat. In barley, B deficiency also depressed the number of spikelets ear^-1 by 23 to 75% and induced a “rat-tail” symptom of terminal spikelet degeneration. There was a weak correlation between ear and flag leaf B and the effect of B on ear size in barley (r = 0.47 and 0.37, respectively, p <0.1). In some barley genotypes, the low B level that depressed grain set sometimes also delayed ear emergence and depressed the number of ears plant^-1 but sometimes increased tillering. These results demonstrate that the phenotypic response to low B is more complex in barley than wheat. Different strategies may be required for managing B nutrition and different approaches for selecting B efficient genotypes in the two species.