Potential Effects of Awn Length Variation on Seed Yield and Components, Seed Dispersal and Germination Performance in Siberian Wildrye (Elymus sibiricus L.)

Abstract

Awns, needle-like structures formed on the distal of the lemmas in the florets, are of interest because of their essential roles in seed dispersal, germination and photosynthesis. Previous research has reported the potential benefits of awns in major cereal grasses, yet reports on the agronomic and economic implications of awn length variation in forage grasses remain scarce. This study investigated the variation of awn length among 20 Siberian wildrye populations and the effect of awn length on seed yield and yield components. This work then studied the impact of awn length on seed dispersal and germination. The analyses indicated a high level of awn length variation among populations. Awn length showed a significant influence on harvested seed yield per plant (p < 0.05) mostly driven by interactions between awn length and the majority of seed yield components. Principal component analysis clearly revealed that the final impact of awn length on seed yield depends on the balance of its positive and negative effects on traits determining seed yield. Furthermore, awn length tended to increase seed dispersal distance, although little diversity in the nature of this progression was observed in some populations. Awn length exhibited a significant relationship (p < 0.05) with germination percentage. It also tended to shorten germination duration, although this interaction was not statistically significant. Collectively, these results provide vital information for breeding and agronomic programs aiming to maintain yield in grasses. This is the first report to demonstrate in Siberian wildrye the agronomic impacts of awn length variation.

The role of wild rice (Oryza rufipogon) awns in seed dispersal

“…In wild rice, seed awning is dominantly controlled by wild functional alleles at several loci, and the plants with the drastic reduction of awn length are hardly produced (Luo et al, 2013;Hua et al, 2015;Bessho-Uehara et al, 2016;Ikemoto et al, 2017;Amarasinghe et al, 2020). In other wild grass species, long awns were also reported to assist seed dispersal and burial (Garnier and Dajoz, 2001;Li et al, 2015;Ntakirutimana et al, 2019). Since these seed movements are essential for the successful seed propagation, their awn lengths may be maintained under similar genetic controls in wild rice.…”

Connectivity assessment and prioritization of urban grasslands as a helpful tool for effective management of urban ecosystem services

“…Dispersal distance threshold. Estimating the dispersal ability of a plant species is difficult because dispersal traits such as pollen vector (wind, insect, self-pollination), reproduction (seed, vegetative growth, and mixed seed and vegetative), and dispersal mode (anemochory, barochory, endo-and/or epi-zoochory) may affect it [61,72,73]. Thomson [74] showed that the mean dispersal capacity of plant species was 203 ± 23 m based on biotic vectors, while it [66] and Wrocław Spatial Information System [69].…”

Unveiling the Actual Functions of Awns in Grasses: From Yield Potential to Quality Traits

“…For the most part, grain yield is decided by grain number and grain weight [ 31 ], with increased grain weight being linked with assimilate availability and distribution [ 32 , 33 ]. Studies investigating the phenotypic evolution of grasses suggest that awns significantly improve grain weight, given their contribution to assimilate production and partitioning [ 6 , 34 , 35 , 36 , 37 , 38 ]. This is particularly true for wheat [ 39 , 40 ] and barley [ 41 , 42 ], where removing the awns significantly reduced grain weight and grain yield.…”

“…It is worth noting that moisture may not always be the deciding factor, as the environments could also vary in temperature, radiation, and soil fertility [ 44 ]. Our study in Siberian wildrye ( Elymus sibiricus L.) demonstrated that the contribution of awns to grain yield and yield components, including grains per inflorescence, thousand-kernel weight, and grain size, varied across latitudes, longitudes, and altitudes [ 35 ]. This indicated not only a complex interaction between environment and awn features but also pointed to multi-lateral impacts of this interaction.…”