NUMBER OF FERTILE FLORETS IN WHEAT: DIFFERENTIATION AND DEATH DYNAMICS AS AFFECTED BY ALLELIC COMPOSITION FOR PPD-1 GENES UNDER CONTRASTING PHOTOPERIODS

THOMAS PEREZ GIANMARCO; SLAFER GA; GONZÁLEZ FERNANDA G

Corrientes

Congreso; XXXI Reunión Argentina de Fisiología Vegetal; 2016

UNNE-CONICET-SAFV

As opposed to what happens tostructures generated during early development (leaves and spikelets), not allof the initiated floret primordia survive and fully develop to reach thefertile stage at anthesis. Evidence suggests intra-plant competition forassimilates during spike growth and floret development period (processes thattake place during late reproductive phase, LRP) determines floret abortion. Changesin the duration of LRP affect that competition and the rate at which floretsdevelop and die altering the number of fertile florets at anthesis (NFF) andhence yield potential. Photoperiod impact on these developmental processes hasbeen well studied, but little is known about the effect genes modulating plantresponse to daylength (Ppd-1) have. Nearisogenic lines (NILs) were grown under contrasting photoperiod (12 and 16 hoursof light). Each NIL carried different combinations of sensitive (Ppd-1b) and insensitive (Ppd-1a) alleles in each genome (A, B andD), provided by different donors, When lit for 12 hours, NILs differed for LRPduration, which affected spike dry weight at anthesis, and ultimately, NFF. Mostfertile plants did not only have more fertile spikelets, but also thesespikelets bore more fertile florets. Lower floret developmental rates wereassociated to higher floral scores achieved.