Abstract: At higher temperatures, lettuce seeds may not germinate, resulting in problems for crop establishment in the field and production. This study aimed to evaluate the maternal effect for thermotolerance on lettuce seeds and find enzymatic markers. We used the thermoinhibition tolerant cultivar ‘Everglades’, the sensitive ‘Verônica’, their reciprocal hybrids, F1 and F2 generation. Seeds were submitted to germination and enzymatic tests (catalase, superoxide dismutase, ascorbate peroxidase, and endo- β-mannanase). Germination (first and final counting) and speed index were compared through Tukey’s test. ‘Everglades’ and its reciprocal hybrids, have not been influenced by temperature regarding germination compared to the other treatments. Also, the maternal effect was observed for the F1 generation. Higher temperatures interfere with the activity of all enzymes evaluated, consequently in the physiological parameters. However, superoxide dismutase and endo- β-mannanase have shown direct and more expressive correlation with changes on the physiological parameters compared to the other enzymes. Thus, it is possible to conclude that those enzymes can be used as markers for thermotolerant genotype selection.

Resumo: Sob altas temperaturas, sementes de alface não germinam, resultando em problemas para o estabelecimento da cultura em condição de campo. Esse trabalho analisou a possibilidade de presença de efeito maternal na termotolerância em sementes de alface e buscou marcadores enzimáticos para tal. Usaram-se as cultivares Everglades (tolerante) e ‘Verônica’ (sensível), bem como seus híbridos recíprocos e a geração F2. As sementes foram analisadas quanto à germinação, bem como atividade enzimática (catalase, superóxido dismutase, ascorbato peroxidase e endo-β-mananase). O percentual de germinação; (primeira contagem e final), bem como a velocidade (IVG) foram analisados por meio de ANOVA e teste de Tukey. A cultivar Everglades e seus híbridos recíprocos não foram influenciados pela germinação em alta temperatura quando comparados com os outros tratamentos. Além disso, o efeito maternal foi observado na geração F1. Altas temperaturas interferem na atividade de todas as enzimas analisadas nesta pesquisa, consequentemente também nos parâmetros fisiológicos. Contudo, a superóxido dismutase e a endo-β-mananase tiveram suas variações altamente correlacionadas com as mudanças nos parâmetros fisiológicos. O presente trabalho evidenciou o efeito materno para a termotolerância em sementes de alface, bem como o uso da superóxido dismutase e endo-β-mananase como marcadores enzimáticos para tal característica.

Abstract The objective of this work was to select sweet potato (Ipomoea batatas) genotypes with leaves with potential to be used for human consumption. Twenty-six experimental genotypes and four commercial cultivars were tested in a randomized complete block design with three replicates and ten plants per plot. The trial was carried out in the municipality of Lavras, in the state of Minas Gerais, Brazil. Leaf shape and lobe, aerial-part yield, edible-leaf yield, edible-leaf percentage, edible-leaf dry mass, and latex production, as well as leaf total chlorophyll, pH, soluble solids contents, titratable acidity, total phenolic compounds, and anthocyanin contents, were evaluated. Roots were characterized as to their pulp and peel colors. Fifteen genotypes presented the highest aerial-part (29.6 to 51.8 Mg ha-1) and edible leaf (7.8 to 12.7 Mg ha-1) yields. In the biochemical analysis, high contents of chlorophyll, total phenolics, and anthocyanins were observed. In addition, pH, soluble solids, and leaf titratable acidity did not differ significantly among the evaluated genotypes. Leaves of ten genotypes are recommended for human consumption.

Resumo O objetivo deste trabalho foi selecionar genótipos de batata-doce (Ipomoea batatas) com folhas com potencial para serem usadas para consumo humano. Vinte e seis genótipos experimentais e quatro cultivares comerciais foram testados em delineamento de blocos ao acaso, com três repetições e dez plantas por parcela. O ensaio foi realizado no município de Lavras, no estado de Minas Gerais, Brasil. Foram avaliados formato e lóbulo da folha, produção da parte aérea, produção de folhas comestíveis, percentagem de folha comestível, massa seca de folha comestível e produção de látex, bem como clorofila total, pH, conteúdo de sólidos solúveis, acidez titulável, compostos fenólicos totais e teor de antocianinas das folhas. As raízes foram caracterizadas quanto às cores da sua polpa e casca. Quinze genótipos apresentaram as maiores produtividades de parte aérea (29,6 a 51,8 Mg ha-1) e de folhas comestíveis (7,8 a 12,7 Mg ha-1). Nas análises bioquímicas, foram observados altos teores de clorofila, compostos fenólicos totais e antocianinas. Além disso, pH, sólidos solúveis e acidez titulável foliar não diferiram significativamente entre os genótipos avaliados. As folhas de dez genótipos são recomendadas para alimentação humana.

ABSTRACT The growing consumer demand for sweet potato roots results in the need for genotypes with higher yields and better root quality. Thus, the objective of this study was to agronomically evaluate sweet potato genotypes via mixed models to select superior genotypes for human consumption and predict their selection gains. The study had a partially balanced triple lattice design with three replicates. As treatments, 92 sweet potato genotypes from the Universidade Federal de Lavras germplasm bank selected in the first selection cycle were evaluated along with eight controls, namely, Brazlândia Roxa, Princesa, Uruguaiana, BRS Amélia, Beauregard, UFVJM-57, UFVJM-58, and UFVJM-61. The treatments were ranked by the mixed linear model via restricted maximum likelihood (REML) and best linear unbiased prediction (BLUP). We highlighted the 15 best genotypes for each agronomic trait, then identified the best ones overall considering all quantitative and qualitative traits. High heritability was found for the trait commercial root yield (56.31%). For all traits, there were selection gains relative to the population mean. The use of mixed models was efficient for the selection of superior sweet potato genotypes. The genotypes 2018-19-464, 2018-72-1409, 2018-72-1428, 2018-19-443, 2018-36-807, 2018-72-1418, 2018-19-455, 2018-72-1376, 2018-54-1137, 2018-54-1114, 2018-65-1249, and 2018-28-556 have good traits related to commercial root yield and root quality and may be recommended for human consumption.