Thermo-photoperiodic responses in buckwheat (Fagopyrum esculentum Moench) cultivar Mancan for modelling crop phenology

GUGLIELMINI AC; ALVAREZ PRADO S; ABELEDO LG; ROCCA CM; MIRALLES DJ

Santa Fe

Congreso; XXXIII Argentinian Meeting of Plant Physiology; 2021

Sociedad Argentina de Fisiología Vegetal

Interest in buckwheat is increasing due to the hight quality protein content and the absence of gluten in its grains (achenes), both attributes being more valued in a food for human consumption. To expand de agricultural frontier of buckwheat it is necessary to know the thermo-photoperiod response. Although it is considered a quantitative short-day plant, there is not a clear characterization of this response throughout all phenological phases of crop cycle. Five field experiments were carried out between 2005-2019 growing seasons. Treatments consisted of a combination of different sowing dates of cultivar Mancan in two locations (CABA and Chacabuco, Buenos Aires) in a randomized complete 3 block design. The photoperiod explored throughout sites and sowing dates ranged from 11.2 to 15.4 hours. Main phenological events: emergence (Em), first flowers open (FFlO), first brown fruits (FBrF) and end of fruit ripening (EFrR) were determined and the duration of phases measured in thermal time units (°Cd, base temperature 5 °C). Crop cycle increased with increases in mean photoperiod explored during Em¬EFrR phase (271.0 ± 30.7 °Cd/hour; r2= 0.70) and should be mainly ascribed to variations in FFlO?FBrF phase (183.3 ± 27.7 °Cd/hour; r2= 0.56). While Em?FFlO and FBrF?EFrR phases showed much lower photoperiod sensitivity responses (72.6 ± 12,2 °Cd/hour; r2= 0.51 and 82.4 ± 15.2 °Cd/hour; r2= 0.45, respectively. The linear relationships found in all cases suggest that optimum photoperiod is shorter than 11.2 hours for this species. Awareness of the photoperiodic sensitivity response of each ontogenic stage will allow calibration to construct simple phenological model.