Agronomic potential of biofortified crisphead lettuce (Lactuca sativa) and its reaction to Root-knot nematodes

Abstract

Lettuce is the most-consumed leafy vegetable in Brazil due to its ease of preparation, nutritional quality, and affordability. Despite these benefits, there are few cultivars of crisphead lettuce (Lactuca sativa) that possess agronomic potential, high carotenoid content and resistance to nematodes. Therefore, we evaluated the agronomic potential of crisphead lettuce genotypes that are resistant to the root-knot nematode. The experiment was conducted at the Vegetable Experiment Station of the Federal University of Uberlandia (UFU), Monte Carmelo Campus. The trial was set up in a randomized block design with 49 treatments (43 genotypes obtained from crosses between Uberlandia 10000 and Belissima and six commercial cultivars) and three replications. After preparing the beds and before transplanting the seedlings, 11 simple samples were taken from each of the three experimental blocks to confirm the presence of nematodes within the experimental area. The following variables were determined 48 days after transplanting: chlorophyll content, leaf temperature, plant diameter, number of leaves per plant, fresh mass and incidence of root gall. The data were submitted to analysis of variance (ANOVA) and an F-test and the means were compared by the Scott-Knott test. Genetic diversity was represented by a dendrogram that was obtained using the hierarchical method of UPGMA and the optimization method of Tocher. We found genetic divergence and agronomic potential among the evaluated genotypes. Specifically, 199#1#1-E, 199#2#1-E, 199#2#2-E, 199#3#1-E, 199#6#1-E and 75#2#2-E presented good agronomic potential, were rich in carotenoids and showed resistance to the root-knot nematode.

Comparison between non-parametric indexes in the selection of biofortified curly lettuce

“…Few researches have been conducted into the biofortified lettuce (Cassetari et al, 2015;Jacinto et al, 2019;Silveira et al, 2019;Sousa et al, 2019). One of the main obstacles is to feasibly get an individual with both good agronomic traits and high level of carotenoids (Maciel et al, 2019a).…”

Genetic dissimilarity between biofortified lettuce genotypes for leaf carotenoid levels

“…Table 4). This disagreement between multivariate methods was also observed by authors who worked with the same species (Sousa et al, 2019;Jacinto et al, 2019). (Bertan et al, 2006;Araujo et al, 2016).…”

“…This demonstrates the great importance of the evaluation of the SPAD index, in the field, for future improvement programs of biofortified lettuces. Corroborating this fact, Sousa et al (2019) and Maciel et al (2019b), found values of 24.84% and 60.31%, respectively, for the same index, being the largest relative contribution among the characteristics evaluated.…”

“…Regarding the stem diameter, the genotype UFU210#1 was statistically superior to the five commercial cultivars evaluated, with an average diameter of 33.30 mm (Table 3). In a study by Sousa et al (2019) (Ekinci et al, 2012;Sublet et al, 2018).…”

“…Comunicata Scientiae, v.11: e3348, 2020 Sousa et al (2020) Genetic dissimilarity between biofortified... (Gomes et al, 2000(Gomes et al, , 2002 261.34%; 261.34%; 249.96% more total chlorophyll than the cultivar Uberlândia 10,000, a cultivar considered rich in beta-carotene (Sousa et al, 2007) (Table 3). Sousa et al (2020) Genetic dissimilarity between biofortified... Continue... Sousa et al (2020) Genetic dissimilarity between biofortified... Sousa et al (2019) (Klooster et al, 2012). In addition, the chlorophyll content is highly related to the concentration of carotenoids in lettuce, suggesting that the SPAD index can be used as an indirect indicator of the content of these pigments in these plants (Cassetari et al, 2015).…”