Desempenho produtivo e qualitativo de cultivares de alface em diferentes épocas de plantio em Mossoró-RN

Abstract

In Rio Grande do Norte to lettuce production is low compared with other regions of the country. Among the factors that are associated with low yields of lettuce produced, we highlight the lack of cultivars adapted to high temperatures and elevated luminosities of the Region. Thus the objective of this research was to evaluate the quality and yield performance of cultivars of lettuce at different planting times on the conditions of Mossoró, RN. Four experiments installed in the field in 21/12/2012, 21/03/2013, 21/06/2013 and 09/23/2013 were developed. Cultivars of the American groups (Angelina, Amelia, Taina), Crespa (Scarlet, Vera, Isabella, Vanda), Mimosa (Mila, Mimosa, Lavinia), and Lisa (Elisa, Regiane) were evaluated in randomized complete blocks with four repetitions. One micrometeorological tower was installed in the experimental area to collect temperature data (° C), relative humidity (%), precipitation (mm) and global solar radiation (Wm-2). In each experiment, production characteristics and quality were assessed: number of leaves, average fresh mass (g) and dry (g) of plants, yield (t ha-1), soluble solids (%), titratable acidity (%) , pH and total soluble sugars (%).Vanda cultivars and Isabela (Crespa) were the ones that better adapted, when grown in winter. In spring, Isabela and Scarlet showed the best results. The ultivar Mila (Mimosa), was who excelled for cultivation in autumn. In winter cultivars indicated for cultivation were: Mimosa and Lavinia who presented the highest yield, and Lavinia is also seconded in the spring. The Regiane (Lisa) stood out in the winter. The American lettuce showed adapted to cultivation in the four epochs evaluated. The Vera, Vanda, Taina, and Elisa, cultivars showed higher pH in the summer and Mila in the spring. The Crespa and Lisa cultivars registered lower titratable acidity in the summer and the Americanas in autumn. The highest levels of SS were obtained in autumn for Vera, Vanda, Isabela, Elisa and Regiane cultivars, in summer and autumn Lavinia, Angelina, Amelia and Taina have excelled from the others times cultivation for this trait. The Scarlet, Angelina and Amelia cultivars showed higher total soluble sugars in the summer, Mila and Lavinia in the spring, Elisa and Regiane in winter, in the spring Taina