Tolerances of oat cultivars to an acid soil high in exchangeable aluminum

Abstract

Aluminum tolerant oat (Avena sativa L.) cultivars are needed for use in rotation with potatoes which require a low soil pH (<5.4) to control the potato scab disease. They would also be valuable where lime is not readily available or prohibitively expensive, or where oats are grown on soils underlain by strongly acid subsoils. However, to date, oat cultivars and germplasm collections have not been systematically evaluated for this trait. Our objective was to determine the range of Al tolerance available among oat cultivars and advanced breeding lines entered in regional experimental nurseries.

Forty‐eight cultivars were grown for 28 days in greenhouse pots of an unlimed, Al toxic, Tatum subsoil at pH 4.3 and in limed Tatum soil at pH 5.7 (3 g kg‐1 CaCO₃). Oat cultivars differed significantly in tolerance to the acid soil. Relative top yields (pH 4.3/pH 5.7%) ranged from 34.2 to 13.1% and relative root yields from 50 to 16.9%. Cultivars showing highest tolerance included Coker 83–23, Glen, Victory, ND 78406, Pierce and Otana. Cultivars showing significantly less tolerance included Fla 501, Fla 502, Carolee, NC 81378 and Cayuse. Acid soil tolerant and sensitive cultivars did not differ in. Ca and Mg concentrations in their tops when grown on unlimed soil at pH 4.3; however, sensitive cultivars tended to accummulate higher concentrations of P, Al and Fe and lower concentrations of K and Mn.

The acid soil tolerant oat cultivars identified show promise for direct use in acid soil situations and for use as breeding materials in combining Al tolerance with other desirable traits in oats.

Key words:

• Avena sativa (L.)
• marginal soils
• acid subsoils
• acid soil rotations
• low input agriculture
• plant breeding
• Al toxicity
• Al tolerance