Evaluation of Switchgrass Genotypes for Cold-Tolerant Seed Germination from Native Populations in the Northeast USA.

Mayton Mayton,Taylor Taylor,Amirkhani Amirkhani,Crawford Crawford,Hansen Hansen,Salon Salon,Loos Loos,Viands Viands

doi:10.3390/plants8100394

Abstract

The focus of this research was to evaluate genotypes for cold-tolerant germination from wild switchgrass (Panicum virgatum L.) populations collected in the Northeast USA. Switchgrass nurseries were established in 2008 and 2009 with seed collected from native stands of switchgrass in the Northeast USA between 1991 and 2008. Switchgrass seed harvested from individual genotypes was evaluated for cold-tolerant germination in a series of laboratory experiments. Germination assays of seed of 13 switchgrass genotypes harvested in the fall of 2016 are the primary focus of this reported research. The selected genotypes were evaluated for cold-tolerant seed germination in three experiments, during the spring of 2017, fall of 2017 and spring of 2018, (with and without stratification) using a 10/15 °C regime with a 12 h photoperiod. Germination tests showed that several genotypes had significantly higher percentage germination as well as faster germination rates expressed as T50 (number of days required to reach 50% maximum germination) when compared to Cave-in-Rock, a moderately sensitive cold-tolerant commercial cultivar established in the original switchgrass nursery as a control. A final germination test was conducted to compare seed from the original population (no selection cycle 0), with one of the top performing cold-tolerant germination genotypes, and a commercial cultivar, ‘Espresso’, developed for low seed dormancy and low temperature germination. In this test, the selected genotype had significantly higher percentage germination in the stratified treatment and was not significantly different than Espresso in the non-stratified test. These data indicate successful selection for cold-tolerant germination in switchgrass genotypes from native germplasm collected in the Northeast USA.

Highlights

Switchgrass (Panicum virgatum L.) is a C4 open-pollinated and genetically diverse warm season perennial grass that can be used for forage, to improve the soil structure and health of overused and marginal farmlands, and as a bioenergy crop [1,2,3,4]
The focus of this research was on evaluation and selection of genotypes with potential to germinate at low temperatures from native switchgrass germplasm collected in the Northeast USA
In the final experiment reported in this study, the cold-tolerant germination genotype NY13 performed as well as the switchgrass cultivar Espresso, which was selected for cold-tolerant germination and low dormancy from a breeding program in Mississippi, USA [11]

Summary

Introduction

Switchgrass (Panicum virgatum L.) is a C4 open-pollinated and genetically diverse warm season perennial grass that can be used for forage, to improve the soil structure and health of overused and marginal farmlands, and as a bioenergy crop [1,2,3,4]. It is a self-incompatible species with nine chromosomes and an array of ploidy levels, most genotypes are either tetraploid or octaploid [5,6]. In addition to adaptation response for vegetative and reproductive growth, studies on cardinal temperatures associated with seed germination showed significant differences within upland and lowland genotypes [11]

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Conclusion