Variation in growth, development, and yield of durum wheat in response to high soil boron. II. Differences between genotypes

Abstract

This greenhouse study examined the variation in growth, development, and yield between 9 durum wheat (Triticum turgidum L. var. durum Desf., syn. T. durum) lines in response to high soil boron (B) levels. The lines were selected to represent the range of B-toxicity tolerance in an earlier screening experiment. Three soil B levels (hot-water extractable B concentrations of 0·3, 7·1, and 17·4 mg/kg, designated as B0, B25, and B50, respectively) were set up by mixing different amounts of boric acid with soil. Foliar B-toxicity symptom score, dry weight, and shoot-B concentration were measured at tillering. Agronomic traits and yield were measured. There were differential responses to high soil B levels between the durum lines. The boron×line interaction was significant for B-toxicity symptom score and shoot-B concentration. Based on these 2 characters, and percentage of shoot dry weight and grain yield reduction from B0 to B50, Oued Zenati, Omrabi-5, and Gezira-17 were the most tolerant of the 9 durum lines, yet they were less tolerant to high soil B levels than the tolerant bread-wheat check, Halberd. Nonetheless, until more tolerant materials are developed, these moderately tolerant durum lines could still be useful for areas, like southern Australia, where B toxicity is a problem.