Photoperiod-sensitivity genes (Ppd-1) shape floret development in wheat.

THOMAS PEREZ GIANMARCO; SLAFER GA; GONZALEZ FERNANDA G

JOURNAL OF EXPERIMENTAL BOTANY

OXFORD UNIV PRESS

Lugar: Oxford; Año: 2019

0022-0957

Lengthening pre-anthesis period of stem elongation (or late reproductive phase, LRP) through altering photoperiod sensitivity has been suggested as an avenue to increase number of fertile florets at anthesis (NFF) in wheat. But little is known about the effects that genes modulating plant response to photoperiod (Ppd-1) may have on reproductive development. Five near isogenic lines for Ppd-D1, Ppd-B1 and Ppd-A1 were grown in growth chambers under contrasting photoperiod (12 and 16 h) to assess the effect of these genes. Under 12 h the NFF followed the order Paragon (three Ppd-1b) > Ppd-B1a (Chinese Spring) > Ppd-A1a (GS100-2A) > Ppd-D1a (Sonora 64-2D) > triple insensitive (three Ppd-1a); (b: sensitive, a: insensitive). Under 16 h differences were milder, but Paragon bore more NFF than the rest. As Ppd-1b alleles lengthened the LRP, spikes were heavier and the NFF increased. For the first time, it was shown that Ppd-1b increased the maximum number of florets initiated through lengthening the floret initiation phase, which partially explained variations in NFF. Nevertheless, the most important impact of Ppd-1b alleles for breeding purposes relay on the increment of floret primordia survival, which determined higher NFF. These findings reinforce the idea that an increased duration of the LRP, achieved through photoperiod sensitivity, would be useful for increasing wheat yield potential.