title: Ppd-1 is a key regulator of inflorescence architecture and paired spikelet development in wheat.
abstract: The domestication of cereal crops such as wheat, maize, rice and barley has included the modification of inflorescence architecture to improve grain yield and ease harvesting(1). Yield increases have often been achieved through modifying the number and arrangement of spikelets, which are specialized reproductive branches that form part of the inflorescence. Multiple genes that control spikelet development have been identified in maize, rice and barley(2-5). However, little is known about the genetic underpinnings of this process in wheat. Here, we describe a modified spikelet arrangement in wheat, termed paired spikelets. Combining comprehensive QTL and mutant analyses, we show that Photoperiod-1 (Ppd-1), a pseudo-response regulator gene that controls photoperiod-dependent floral induction, has a major inhibitory effect on paired spikelet formation by regulating the expression of FLOWERING LOCUS T (FT)(6,7). These findings show that modulated expression of the two important flowering genes, Ppd-1 and FT, can be used to form a wheat inflorescence with a more elaborate arrangement and increased number of grain producing spikelets.
authors.affiliation: CSIRO Agriculture Flagship, GPO Box 1600, Canberra, ACT 2601, Australia.
authors.forename: Scott A
authors.initials: SA
authors.lastname: Boden
authors.affiliation: CSIRO Agriculture Flagship, GPO Box 1600, Canberra, ACT 2601, Australia.
authors.forename: Colin
authors.initials: C
authors.lastname: Cavanagh
authors.affiliation: National Institute for Applied Statistics Research Australia (NIASRA), School of Mathematics &Applied Statistics, University of Wollongong, New South Wales, 2522, Australia.|CSIRO Digital Productivity Flagship, GPO Box 1600, Canberra, ACT 2601, Australia.
authors.forename: Brian R
authors.initials: BR
authors.lastname: Cullis
authors.affiliation: CSIRO Agriculture Flagship, GPO Box 1600, Canberra, ACT 2601, Australia.
authors.forename: Kerrie
authors.initials: K
authors.lastname: Ramm
authors.affiliation: CSIRO Agriculture Flagship, GPO Box 1600, Canberra, ACT 2601, Australia.|Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia.
authors.forename: Julian
authors.initials: J
authors.lastname: Greenwood
authors.affiliation: CSIRO Agriculture Flagship, GPO Box 1600, Canberra, ACT 2601, Australia.
authors.forename: E
authors.initials: E
authors.lastname: Jean Finnegan
authors.affiliation: CSIRO Agriculture Flagship, GPO Box 1600, Canberra, ACT 2601, Australia.
authors.forename: Ben
authors.initials: B
authors.lastname: Trevaskis
authors.affiliation: CSIRO Agriculture Flagship, GPO Box 1600, Canberra, ACT 2601, Australia.
authors.forename: Steve M
authors.initials: SM
authors.lastname: Swain