Review: evolutionary drivers of agricultural adaptation in Lolium spp.

Abstract

The genus Lolium comprises many species, of which L. perenne ssp. multiflorum, L. perenne ssp. perenne, and L. rigidum are of worldwide agricultural importance as both pasture crops and as weeds. These three species are inter‐fertile, obligate out‐crossers with a self‐incompatible reproduction system. This combination contributes to high genetic diversity that supplies new variants during expansion to new natural areas and agricultural environments. Human dispersal, de‐domestication and crop‐weed hybridization events between Lolium spp., or with others such as Festuca spp., are likely associated with their distinct weediness abilities. Furthermore, new introductions followed by introgression may hasten adaptation to new environments. Most Lolium‐related weed science studies have focused on adaptation leading to herbicide resistance, but other forms of adaptation may also occur. In this review, we explore how the wide genetic variation among Lolium species and hybridization with other species may contribute to range expansion, and adaptation to both new agricultural practices and future predicted climate change scenarios. © 2020 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

The Remarkable Journey of a Weed: Biology and Management of Annual Ryegrass (Lolium rigidum) in Conservation Cropping Systems of Australia

“…The research comparing the influence of the differing levels of soil disturbance and residue levels in minimum, no- and/or zero tillage systems on seedbank distribution and persistence is limited and inconclusive. Continuous cropping systems have been selected for higher dormancy in annual ryegrass populations compared to more disruptive systems with a pasture phase or break crops [ 28 ].…”

Enhanced production of water‐soluble cinmethylin metabolites by Lolium rigidum populations with reduced cinmethylin sensitivity

“…is the most economically damaging weed of southern Australian cropping systems and is also a major problem in parts of Africa, Europe and the Middle East. 1,2 In response to repeated and intensive use of selective post-emergence herbicides inhibiting acetyl-CoA carboxylase and acetolactate synthase, annual ryegrass populations have developed widespread resistance to these modes of action, and growers are returning to soil-applied pre-emergence herbicides to maintain adequate levels of weed control. 3 Inevitably, this has led to an increasing frequency of resistance to pre-emergence herbicides such as trifluralin (an inhibitor of microtubule assembly, mode of action group 3), and prosulfocarb, triallate and pyroxasulfone (inhibitors of very-long-chain fatty acid biosynthesis, group 15), [4][5][6] with most resistant populations exhibiting resistance to two or more of these herbicides.…”

Population genomics of Digitaria insularis from soybean areas in Brazil

“…This may also enable populations to adapt more rapidly to the management practices other crop production systems. 23 Our H E results indicate that the magnitude of D. insularis dispersion is greater than observed in the outcrossing weed species Alopecurus myosuroides , where it was found that H E varied from 0.09 to 0.14, approximately, in populations exhibiting different patterns of herbicide resistance. 24 Similarly, the H E value of D. insularis is larger than that of the predominantly self‐pollinated weed species Bromus tectorum which exhibited a mean H E of 0.2.…”