Postharvest Quality of Cut Zinnia Flowers Cultivated Under Different Irrigation Levels and Growing Seasons

Abstract

The quality of floral stems depends on a set of pre-harvest factors which can influence their postharvest longevity. Although the identification of visual signs of senescence through scales is decisive in assessing the loss of floral quality in the postharvest period, this scale does not exist for zinnia flowers (Zinnia elegans Jacq.). Thus, the objectives of this study were to evaluate the effect of different irrigation levels and growing seasons on the postharvest longevity of zinnia floral stems; and to determine a senescence scale to assess their durability. Therefore, zinnia plants (cv. “Red California Giant”) were cultivated in pots inside a greenhouse in Seropédica (Rio de Janeiro, Brazil), with a randomized block design, under four irrigation levels (46%, 64%, 75% and 100% of the species’ water requirement) and two cycles (autumn-winter and winter-spring). At the end of each cycle, 48 stems from each treatment were harvested and placed in containers holding 300 mL of supply water. For all irrigation levels and crop cycles, there was an increase in the fresh stem weight on the first days after harvesting and the water absorption rate was higher on the first day of evaluation. The proposed senescence scale allowed us to evaluate the loss of floral quality in the postharvest period. The stems from both cycles had satisfactory results, mainly of commercial longevity and the score 5 on the scale, which represents 100% of the stems’ market value. The main postharvest results of the zinnia floral stems were not influenced by the irrigation levels.

Evaluation of some garden flowers as specialty cut flowers in Eskisehir province-Türkiye

“…However, the average stem length in July was 48.1 cm. The minimum acceptable stem length for post-harvest evaluation of Zinnia elegans plants is considered to be 30 cm ( Martins et al, 2021 ). In Tagates erecta , the minimum stem length (24.9 cm) was determined in October at the last harvest.…”

Production and quality of zinnia under different growing seasons and irrigation levels

“…The harvest moment was established when the flower petals were fully open, with the true central flowers beginning to open and when the stems were at least 30 cm long, defined in this study as the minimum marketable length. It is important to note that there are no official standards for the length of floral stems of cut zinnia, and the stem length proposed in this study was based on values commonly used for this species in previous studies (Carlson et al, 2015;Martins et al, 2021).…”

“…Zinnia holds a prestigious position in the flower cut industry for its versatility, numerous colors and low maintenance in the field (Iqbal et al, 2012). Besides that, the longevity of its flowers, which can reach 21 days, is an important characteristic for the cut flower market (Martins et al, 2021).…”