Germinação e desenvolvimento de plântulas de girassol ornamental em substratos

Abstract

The ornamental sunflower is a growing crop in recent years due to its rapid return on investment and expressive representation in the flower market, and research on the ideal substrate for seedling production is essential to maximize information for the crop. Thus, the objective was to evaluate the germination and development of ornamental sunflower seedlings in different substrates compositions. The experiment was installed in a greenhouse, where they were put to germinate, seeds of sunflower type “Vincent’s Choice” in poliestileno trays on substrates with or without addition Slow Release Fertilizer (SRF) at the dose 2 g L-1. The experimental design was completely randomized with 4 treatments [T1- Charcoal + pine bark + peat + expanded vermiculite (1:1:1:1), T2- Coconut fiber + carbonized rice hull + peat + expanded vermiculite (1:1:1:1), T3- Charcoal + pine bark + peat + expanded vermiculite (1:1:1:1) + SRF, T4- Coconut fiber + Carbonized rice hull + peat + expanded vermiculite (1:1:1:1) + SRF] with 8 replicates of 8 seeds, totaling 64 seeds per substrate. It was evaluated: the percentage, index and average germination time, chlorophyll content, length, fresh and dry mass of shoot and root. It was observed that there was no difference in the percentage of germination, but T2 and T4 promoted emergency in the lowest mean time (3.19 and 3.46 days, respectively) with a higher rate of velocity (2.43 and 2.25 respectively), still, T4 presented increments with more than 50% of fresh and dry mass. Thus, it is concluded that the T4 substrate is recommended for germination and development of ornamental sunflower type “Vicent’s Choice”.