Linkage mapping evidence for a syntenic QTL associated with flowering time in perennial C4 rhizomatous grasses Miscanthus and switchgrass.

Elaine Jensen,Kerrie Farrar,Timothy Swaller,Gancho T Slavov,Paul Robson,Desalegn D Serba,Sian Thomas Jones,Iain Donnison,Daniel P Smith,Richard Flavell,Malay C Saha,Xue‐Feng Ma,Reza Shafiei,John Clifton‐Brown

doi:10.1111/gcbb.12755

Abstract

Flowering in perennial species is directed via complex signalling pathways that adjust to developmental regulations and environmental cues. Synchronized flowering in certain environments is a prerequisite to commercial seed production, and so the elucidation of the genetic architecture of flowering time in Miscanthus and switchgrass could aid breeding in these underdeveloped species. In this context, we assessed a mapping population in Miscanthus and two ecologically diverse switchgrass mapping populations over 3 years from planting. Multiple flowering time quantitative trait loci (QTL) were identified in both species. Remarkably, the most significant Miscanthus and switchgrass QTL proved to be syntenic, located on linkage groups 4 and 2, with logarithm of odds scores of 17.05 and 21.8 respectively. These QTL regions contained three flowering time transcription factors: Squamosa Promoter‐binding protein‐Like, MADS‐box SEPELLATA2 and gibberellin‐responsive bHLH137. The former is emerging as a key component of the age‐related flowering time pathway.

Highlights

C4 biomass grasses such as sugarcane (Saccharum officinarum), sorghum (Sorghum bicolor), Miscanthus (Miscanthus spp.) and switchgrass (Panicum virgatum) are some of the most photosynthetically efficient species in the plant kingdom
FS1 was the day of year (DOY) when the first flag leaves emerged; FS2 was the DOY when 1 cm or more of the panicle was showing on at least one stem; FS3 was the DOY when approximately 50% of stems contributing to canopy height had exerted more than 1 cm of panicle; and FS4 was the DOY when more than 80% of the stems contributing to canopy height had exerted greater than 1 cm of the panicle
Mapping populations generated from the perennial grasses M. sinensis and switchgrass exhibited a wide variation in flowering time

Summary

Funding information

Biotechnology and Biological Sciences Research Council, Grant/Award Number: BB/CSP1730/1, BB/E014933/1, BB/ G016216/1, BBS/E/W/10963A01A and BB/K01711X/1; Department of Energy, Bioenergy Research Center, Grant/ Award Number: DE-AC02-05CH11231; Department for Environment, Food and Rural Affairs, Grant/Award Number: NF0426; CERES, Grant/Award Number: LK0863

| INTRODUCTION

| MATERIALS AND METHODS

| RESULTS

Findings

| DISCUSSION