Enhancing white lupin (Lupinus albus L.) adaptation to calcareous soils through selection of lime-tolerant plant germplasm and Bradyrhizobium strains

Abstract

Aims This study aimed to determine whether white lupin adaptation to moderately calcareous soils could be enhanced by lime-tolerant plants and Bradyrhizobium strains. Methods Fourteen landraces from Italy, Morocco and Egypt and some cultivars were grown in moderatelime (ML) and low-lime (LL) soil with each of two inoculants, one commercial and one including three Bradyrhizobium strains well-nodulating under ML soil (isolated from other lupin species). Grain yield and above-ground biomass were assessed in large artificial environments that mimicked field conditions. Shoot, root and nodulation traits at onset of flowering were studied in a pot experiment. Results ML soil severely reduced plant yield, growth and nodulation but increased the harvest index relative to LL. Top-yielding genotypes for grain yield displayed significant rank inversion across soil types (P < 0.05). Limetolerant genotypes reduced their nodulation in ML soil less than limesusceptible ones. Some landraces outperformed the reference lime-tolerant cultivar Giza 1 in ML soil. One Italian landrace had a lime-tolerant response across agricultural locations. The Moroccan inoculant provided greater nodulation, more shoot residues but similar grain yield in ML soil, and less grain and shoot residues in LL soil, compared with the commercial inoculant. Conclusions Lupin adaptation to ML soil can be improved mainly through selection of lime-tolerant plants.

Microvirgasp. symbiovar mediterranense nodulatesLupinus cosentiniigrown wild in Morocco

“…Indeed, Bradyrhizobium has been isolated from root nodules of L. cosentinii in Morocco (Thami Alami et al . ; Annicchiarico and Thami‐Alami ), but, to our knowledge, this is the first report on the isolation of Microvirga from L. cosentinii naturally occurring in the Maamora forest.…”

How a phosphorus‐acquisition strategy based on carboxylate exudation powers the success and agronomic potential of lupines (Lupinus, Fabaceae)

“…Tang et al (1995) found that lime‐induced chlorosis in L. angustifolius is not associated with calcium sensitivity, because the same concentration of calcium provided as calcium sulfate has no inhibitory effect, although it does enhance calcium concentrations in leaves. White lupines vary genetically in their tolerance of calcareous soil; therefore, breeding for this trait is an option (Christiansen et al, 1999; Liu and Tang, 1999; Raza et al, 2001; Annicchiarico and Thami Alami, 2011).…”

The future of lupin as a protein crop in Europe

“…Summer drought and progressive soil salinization are major climatic stresses in Mediterranean areas, yet information is lacking on the intrinsic genetic variation for drought tolerance, particularly in white lupin. Poor adaptation to calcareous soils is probably the main limit to the crop expansion, but white lupin landraces from Egypt or Italy that display tolerance to free calcium have been identified ( Annicchiarico and Thami-Alami, 2012 ). The primary source of phosphate fertilizer (mined rock phosphate) is considered likely to be depleted within 40 years, emphasizing the importance of sustainable P management.…”