Australian researchers published a perennial wheat study that documents how the crop accumulates dry matter above and belowground throughout its regrowth cycles, indicating that dry matter under perennial wheat could surpass that of annual wheat over the course of perennial wheat’s 4-year life cycle observed in southern Australia.

Abstract

Perennial wheats produced grain for up to 4 years in southern Australia, but quantitative data are lacking on dry matter (DM) allocation above- and below-ground over regrowth cycles. This paper examines performance of 4 perennial wheats (147235a [235a], 147280b [280b], OK7211542 [OK72] and 11,955), a perennial grass (148055 [055]), and a replanted-annual bread wheat (Wedgetail) over 3 years in large soil columns. By year 3, total DM increased to 137 g pl⁻¹ in perennial wheat and 194 g pl⁻¹ in perennial grass, but remained at 55 g pl⁻¹ in annual wheat. In the annual wheat, a higher proportion of its root DM was in the 30–60 cm layer with none below 120 cm, while perennial wheats increased their root DM below 60 cm each year, and perennial grass had the most below 120 cm. By the third year, spike DM was 11, 39, 25, 20, 11 and 5 g pl⁻¹ for Wedgetail, perennial wheats 11,955, OK72, 235a, 280b, and perennial grass, though Wedgetail was bird damaged. The results demonstrated that perennial wheats could exceed annual wheat in total and especially deep root DM, and with spike DM equalling or exceeding the annual wheat by the third year. Contrary to previous reports, any reduction in performance in later cycles was associated with lower spike DM pl⁻¹, rather than reduced plant stand, following exposure to moderate water deficit in the previous dry season. Annuals and perennials differed in DM allocation; perennial wheat prioritised roots over shoots, until a suitable foundation was established.