Soil acidity poses a significant challenge to wheat cultivation in Western Australia, affecting over 75% of the wheatbelt soils. This study investigated the performance of four wheat (Triticum aestivum L.) lines with putative large (L1, L3) and small (S1, S2) rhizosheath size, and the commercial cultivar Mace (P). Plants were grown in pots filled with slightly acidic or highly acidic soil with high aluminium (Al3+) content, in a temperature-controlled glasshouse, from June to October 2023.

We assessed various parameters including seedling emergence, tiller number, plant height, rhizosheath size, and root and shoot biomass. Tiller numbers ranged from 3.3 to 4 per plant in the slightly acidic soil, and 1 to 2.3 per plant in the highly acidic soil with high Al3+. Under the highly acidic soil with high Al3+ content, L1 and L3 exhibited significantly greater rhizosheath soil dry and fresh weights, as well as root biomass compared to S1 and S2 at tillering (Z15/Z22) (P < 0.05); however, no such difference was observed under slightly acidic soil.

All wheat lines displayed larger rhizosheath size under the slightly acidic soil than under the highly acidic soil with high Al3+ content. The root: total plant biomass ratio remained consistent across the four lines and the cultivar Mace in both soil types, indicating no impact of soil type or rhizosheath size on biomass allocation to the root system.

Overall, these results confirmed the variation in rhizosheath size among the wheat lines, highlighting genotype-specific responses to soil acidity with high Al3+ content. Such findings have implications for crop growth and yield under acidic soil conditions.

Further investigations are warranted to elucidate the underlying mechanisms driving these responses and the dynamics of rhizosheath development and root traits for wheat genotypes cultivated in highly acidic soils with high Al3+ content.