Avaliação de cultivares de alface crespa produzidas em - Unesp

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Palavras-chave: ambientes, cultivares, cultivo sem solo, Lactuca sativa L.,
sistema hidropônico-NFT
EVALUATING CRISPY LETTUCE CULTIVARS PRODUCED UNDER THE NFT-
HYDROPONIC SYSTEM IN TWO TYPES OF ENVIRONMENTALS IN RIBEIRÃO
PRETO, STATE OF SÃO PAULO, BRAZIL
SUMMARY - Due to changes in feeding habits, lettuce consumption has
been increasing and must be supplied daily throughout the year. As a result, many
producers have adopted hydroponics’ cultivation. In spite of this, many cultivars are
not yet adapted to this technology. The objective of this study was to evaluate the
performance of five lettuce cultivars grown in two environmentals in NFT (“Nutrient
Film Technique”) hydroponic system in the period from Feb/06 to Apr/07 2006 in
Ribeirão Preto, state of São Paulo, Brazil. To accomplish this, cultivars Pira Roxa,
Pira Vermelha, Locarno, Crespona gigante, and Verônica were evaluated in
conventional and climatizated greenhouse in the NFT system. A randomized-block
experimental design was used, consisting of five cultivars in three blocks. Harvest
was performed 61 days after seeding. Evaluations were made for fresh and dry
mass of the aerial part, stem, and roots; number of leaves larger than 10 cm; and
total number of leaves. Cultivar Crespona gigante in fresh weight and dry matter of
the aerial part did not differ from cultivar Verônica, but it was superior to them
cultivars Pira Roxa, Pira Vermelha and Locarno.The cultivars Pira Roxa and Pira
Vermelha suggested a better adaptation, showing better resistance to bolting.
There was no significant effect of the cultivars × environments interaction,
demonstrating that the cultivars had similar behaviors in both environments. There
was a larger consumption of water by the lettuce plants under the conventional
greenhouse conditions in comparison to the acclimated one, probably due to their
higher temperatures and lower air relative humidities. The extraction of nutrients by
leaves lettuce plants (average five to cultivate) obeyed to the followed the
decreasing order: K>N>Ca>Mg>P>S>Fe>Mn>Zn>Cu.