Characterization of manganese use efficiency in UK wheat cultivars grown in a solution culture system and in the field

Abstract

The aim of the research was to describe and characterize the physiological basis of Mn use efficiency among a range of old and modern UK wheat cultivars grown in Mn-depleted solution culture and to ascertain whether the existence of Mn use efficiency conferred a yield advantage under manganese stress conditions in the field. Results of solution culture experiments demonstrated that the old spring wheat cv. Maris Butler is relatively Mn efficient when grown in Mn-deficient conditions in comparison with both a modern winter wheat, cv. Claire, and a modern spring wheat, cv. Paragon. The mean dry weight gain of plants of cv. Maris Butler grown in Mn-depleted nutrient solution was 0·49 of that shown by plants in Mn-sufficient culture, whereas in cvs. Paragon and Claire the equivalent values were 0·38 and 0·21 respectively. When grown in Mn-deficient soil in a farm-based field trial, cv. Maris Butler showed significantly improved (P<0·05) dry matter accumulation and grain yield compared with other spring wheats including cv. Paragon. There was no significant variation in leaf Mn content between the cultivars examined, either under sufficient or depleted Mn supply; however, cv. Maris Butler showed both a relatively high maximum light-saturated rate of photosynthesis and a high photosynthetic apparent quantum yield (based on O₂ evolution) when grown under Mn deficiency. It is argued that the apparent Mn use efficiency of cv. Maris Butler is related to superior internal utilization of Mn, resulting in an increased photosynthetic photosytem II efficiency rather than improved Mn uptake and accumulation. The results suggest that the wheat cultivar Maris Butler may provide a potentially useful source of parental material for future crop improvement programmes designed to produce wheat lines resistant to depleted Mn supply.