2017 ASHS Annual Conference

This study was carried out to determine potential benefits of additional far-red or ultra-violet light spectrums in indoor production of edible pansy which was mainly growing under combined red and blue lighting. Viola Sorbet XP Purple (viola cornuta) was materialized in this study. The seeds were germinated and grown indoor condition of LED 180 μmol·m-2·s-1 PPFD with 18 daylength and 25℃ atmosphere temperature. After 60 seedling days, the plants were treated by different wavelength light spectrums: red-blue (RB, T1), RB with far-red (RBFR, T2), RB with ultra-violet (RBUV, T3), or white (W, T4) with the same light intensity as seedling stage. The treated plants were exposed daily to 11.7 mol·m-2·d-1 PPFD. As results, flower yield was highest in T2 (far-red added) in addition to shoot extension growth which was highest in T2 as well and lowest in T3 (UV-added). Flower quality was partly affected by light wavelength, and petal color or anthocyanin contents were typically affected by UV-band. However UV treatment was partly beneficial or detrimental to edible pansy production. The cause of beneficial effects of FR can be discussed in relation to light-dominant LDPs (Runckle et al., 2003; Randall and Lopez, 2013), related to phytochrome activity R+FR Emerson Effect (Emerson, 1957), shade stretch, or plant heating (no data). Also the positive effect of FR would be derived from high R : FR ratio (2.3) which was 1.1 in natural sun lighting system. Conclusively additional FR lighting can be applicable to increasing the petal yield of edible pansy indoor production.