Phenological characterization of near-isogenic sunflower families bearing two QTLs for photoperiodic response

FONTS, C.; ANDRADE, F.H.; GRONDONA, M.; HALL, A.J.; LEÓN, A.

CROP SCIENCE

Crop Science Society of America

Lugar: Madsion, WI, EE.UU.de N.A.; Año: 2008 vol. 48 p. 1579 - 1585

0011-183X

Understanding the effects of environmentand genotype on crop phenology is critical toachieving appropriate adaptation of cultivarsto targeted production areas. The main objectiveof this work is to examine the phenology ofnear-isogenic sunfl ower (Helianthus annuus L.)families bearing all combinations of alleles forquantitative trait loci (QTLs) A and B associatedwith photoperiodic response growing in controlledenvironment chambers under short andextended photoperiods. Plants were harvestedat intervals, the apices dissected out, and apexdevelopment from the start (apex transformation)to the end of fl oral differentiation scoredusing a 10-point scale of fl oral stages. Parentallines showed signifi cant (p < 0.05) contrastingresponses to photoperiod. The genotypesexhibited signifi cant (p < 0.0001) effects of photoperiod,QTL, QTL × photoperiod, and QTL ×QTL interactions for the timing of apex transformation(B0) and for the inverse of rate of developmentduring fl oral differentiation (B1). Thestrong QTL A × QTL B interaction for both B0and B1 refl ects the much greater delay in developmentunder both photoperiods when QTL Awas derived from HA89 and QTL B from ZenB8.This effect on B1, but not on B0, increasedunder extended photoperiod in the same family,refl ecting a three-factor (QTL A × QTL B ×photoperiod) interaction acting on rate of developmentduring the fl oral differentiation process.Given the weight of direct and interaction contributionsassociated with the two QTLs to thenonerror variability of both B0 and B1 acrossgenotypes and photoperiods, we conclude bothQTLs are important effectors in the photoperiodiccontrol of fl owering in sunfl ower.