Prospects for Hybrid Breeding in Bioenergy Grasses

Abstract

Biofuels obtained from biomass have the potential to replace a substantial fraction of petroleum-based hydrocarbons that contribute to carbon emissions and are limited in supply. With the ultimate goal to maximize biomass yield for biofuel production, this review aims to evaluate prospects of different hybrid breeding schemes to optimally exploit heterosis for biomass yield in perennial ryegrass (Lolium perenne L.) and switchgrass (Panicum virgatum), two perennial model grass species for bioenergy production. Starting with a careful evaluation of current population and synthetic breeding methods, we address crucial topics to implement hybrid breeding, such as the availability and development of heterotic groups, as well as biological mechanisms for hybridization control such as self-incompatibility (SI) and male sterility (MS). Finally, we present potential hybrid breeding schemes based on SI and MS for the two bioenergy grass species, and discuss how molecular tools and synteny can be used to transfer relevant information for genes controlling these biological mechanisms across grass species.

Inheritance patterns of the response to in vitro doubled haploid induction in perennial ryegrass (Lolium perenne L.)

“…In practice, access to DH production and its associated benefits is therefore restricted to the few crops in which methods are sufficiently developed to allow routine application, such as barley, tobacco (Nicotiana tabacum L.) and rapeseed (Brassica napus L.) (Seguí-Simarro 2015). Despite the relatively advanced state of DH techniques in perennial ryegrass (Lolium perenne L.), the world's most economically valuable forage crop, they are not yet part of the standard repertoire of researchers and breeders (Arias Aguirre et al 2011;Pembleton et al 2015). A self-incompatibility system prevents efficient development of inbred lines in this species (Cornish et al 1979), so that DH induction through androgenesis may well be the most practical way to obtain homozygous germplasm and thus enable, for instance, hybrid seed production (Begheyn et al 2016a).…”

Development and Testing of Cool-Season Grass Species, Varieties and Hybrids for Biomass Feedstock Production in Western North America

“…Our study demonstrated useful methods of producing hybrid seed for allogamous plants on a field scale, which has been a considerable challenge in perennial grass breeding [15,26]. Our approach worked effectively for crosses of 4X CWR and 4X BWR, but it did not work in crosses of 4X CWR and 8X BWR.…”

“…This approach of half-sib hybrid seed production, using one clonally propagated seed parent, creates opportunity to select individual genets that have good combining ability and also provides a rapid way to introduce novel genes into hybrid populations. Although similar approaches of producing full-sib single-cross hybrids has been proposed by clonal propagation of two self-incompatible genets, the difficulty of clonal propagation limits the application of this approach in perennial ryegrass (Lolium perenne) or switchgrass [15].…”

“…The development and testing of intraspecific and interspecific hybrids has been a focal point of breeding and genetic research in bioenergy grasses [15], including switchgrass and miscanthus. One of the most productive forms of miscanthus (Miscanthus × giganteus) is a sterile hybrid between Miscanthus sacchriflorus and Miscanthus sinensis that is clonally propagated by rhizomes [1,[16][17][18][19].…”

Haploid and Doubled Haploid Techniques in Perennial Ryegrass (Lolium perenne L.) to Advance Research and Breeding

“…Strategies to accelerate perennial ryegrass breeding in order to increase yield gains have been, and are being, discussed [56,[79][80][81][82], but the role that DH techniques could play in this context has hardly ever been considered. DH techniques have the potential to help unlock and increase the genetic variation available for selection, as well, as facilitate the development of more rapid and efficient selection and breeding procedures [83].…”