Page 152 - PC2019 Program & Proceedings

PLANT CANADA 2019

S89. Analyzing the effects of nitrogen fertilizer source on flower bud induction in day-neutral
strawberry
*
Paul, A. ; V. Gravel
McGill University

Day-neutral strawberry varieties have been developed apart from short-day and everbearing varieties to
produce fruit irrespective of photoperiod, allowing for an extended harvest season and higher yields. The
use of day-neutral strawberry in Canada, as an alternative to short-day, is a promising pursuit to increase
annual strawberry yields and address increasing strawberry demands. However, research on the optimal
environmental and fertilizer conditions of day-neutral strawberry is limited, particularly in the transplant
stage of cultivation. It is the purpose of this study to further the understanding of day-neutral production
in Quebec through observing different sources and concentrations of nitrogen and develop a treatment for
optimal flower bud induction in developing transplants. The study was performed for six-weeks and
considers nitrate, ammonium, and urea sources of nitrogen at 50g/L, 100g/L and 150g/L concentrations in
solution. All other essential nutrients were balanced to deliver optimal concentrations, avoiding the
combination of multiple nitrogen sources. During the six weeks, phenology data, rate of photosynthesis,
relative growth rate, and soil microbial activity were observed to determine the nitrogen treatment that
provides the most optimal results. Preliminary results have shown that the use of higher concentrations of
urea has resulted in the greatest production of flower buds each week. A relationship was also established
between the photosynthetic performance of plants and the source of nitrogen used.

Angela Paul (angela.paul@mail.mcgill.ca)

S90. Light quality and night interruption controls morphogenesis and flowering time in day neutral
strawberry
*
Sidhu, V. ; V. Gravel; S. Jabaji
McGill University

Light quality, referring to wavelength and photoperiod regulate strawberry flowering time, phenological
growth and consequently, fruit production. While the light quality and photoperiodic control of flowering
has been extensively studied in short day (SD) strawberry, little is known about day neutral (DN)
cultivars, despite their rising popularity. This study determines the effect of light quality and night
interruption (NI) on flower bud induction (FBI), morphogenesis and transcription of flowering gene,
FLOWERING LOCUS (FvFT1), in Fragaria vesca cv ‘Alexendria’. Seedlings were grown under far-red
(760nm) and blue (450nm) light emitting diodes (LEDs) at a ratio of 5:1 and 1:5, supplied with long-day
(LD) photoperiod (16h light/8h dark). LD photoperiod supplemented with higher blue light resulted in a
significant (p<0.05) increase in leaf growth and flower bud induction compared to far-red light during
transplant production. Additionally, it was observed that flowering time and expression of FvFT1 can be
stimulated by blue light quality. As a second step, seedlings were exposed to photoperiods of 10h (SD),
15h (LD), 10h (8h+2NI) and 15h (13h+2NI) using fluorescent lights in growth chambers under controlled
conditions (25/20°C and 70% RH). Plants treated with 13h+2NI significantly induced flower bud
differentiation compared to 8h+2NI. The study implies that flowering in DN strawberry can be
accelerated with increased ratio of blue to far-red light supplemented during night interruption.

Varinder Sidhu (Varinder.sidhu@mail.mcgill.ca)

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