Mapping QTLs for spring green-up, plant vigor, and plant biomass in two lowland switchgrass populations

Abstract

Switchgrass ( Panicum virgatum L.) is an important perennial cellulosic bioenergy species. Identi cation of quantitative trait loci (QTL) controlling important developmental traits is valuable to understanding the genetic basis and breeding high-yielding cultivars. One F 1 hybrid population consisting of 176 individuals derived from NL94 ( ) × SL93 ( ), and one S 1 ( rst-generation selfed) population of 265 individuals from NL94, were used to study spring greenup, plant vigor and plant biomass in switchgrass. Both populations showed signi cant variations for genotype, and genotype by environment interactions for the three traits. Plant vigor had strong and positive correlations with plant biomass in both populations. Broad sense heritability estimates of plant vigor ranged from 0.46 to 0.74 and 0.45 to 0.74 in the hybrid and selfed population, respectively. Spring green-up had similar heritability estimates in these two populations (0.42-0.78 in hybrid population, 0.47-0.82 in selfed population). The heritability of plant biomass was above 0.5 (0.54-0.64 in hybrid population, 0.64-0.74 in selfed population). Fifteen and four QTLs were detected for spring green-up in the hybrid and selfed population, respectively. Six and four QTLs were detected for plant vigor in the hybrid and selfed population, respectively. Three QTLs in the hybrid population and one QTL in the selfed population were identi ed for plant biomass. This study provided new information in understanding the genetic control of biomass components and demonstrated substantial heterotic vigor that could be explored for breeding hybrid cultivars in switchgrass.