03938nab a2200313 i 4500003000900000005001700009008004100026040001800067072001400085072000800099100002800107100003300135100002400168100003200192100002300224100002400247245011600271500006600387520131700453520151301770650001103283650001203294650001903306650001603325650001603341650002803357773016203385856007703547BR-BrBNA20250917160002.0250917b2022    bl.qr|pooa||| 00| 0 eng |  aBR-BrBNAbeng  aF30b1660  aF03  aCatão, Hugo Cesar RM   aGomes, Luiz Antonio Augusto   aAzevedo, Alcinei M   aSiquieroli, Ana Carolina S   aMaciel, Gabriel M   aFreitas, Pamela GN   aEarly flowering, genetic dissimilarity and clustering of lettuce cultivars with thermoinhibition tolerant seeds  a
Publicação online; 31 ref.; 4 illus.; Summaries (En, Pt)  a


ABSTRACT:    High temperatures interfere with lettuce cropping. Thermoinhibition of seed germination and early flowering cause important losses for farmers. The objectives of this work were to evaluate the tolerance to early flowering, to verify the genetic dissimilarity and to select lettuce cultivars tolerant to seed thermoinhibition. 18 cultivars were evaluated. The number of days until the first anthesis was verified for early flowering. Regarding seed thermoinhibition, the first and final germination counting and germination speed index were evaluated, using temperatures of 20, 25, 30 and 35ºC. The analyses were performed immediately after harvest and after six months under storage. The genetic dissimilarity was obtained using the Tocher Graph optimization and hierarchical UPGMA methods. Regression models were adjusted, and curves’ clustering was performed by testing the identity of the models. Early flowering was observed in cultivars Floresta, Colorado, Grand Rapids, and Everglades. Cultivars showed genetic variability and are dissimilar regarding tolerance to thermoinhibition. By clustering the regression equations, it was possible to select thermoinhibition tolerant cultivars. 


Keywords:     Lactuca sativa, anthesis, genetic variability, multivariate statistics, temperature.  a


RESUMO:    As altas temperaturas interferem no cultivo da alface. A termoinibição da germinação das sementes e florecimento precoce causam perdas importantes para os produtores. Os objetivos deste trabalho foram avaliar a tolerância ao florescimento precoce, verificar a dissimilaridade genética e selecionar cultivares de alface tolerantes à termoinibição de sementes. Foram avaliadas 18 cultivares. Para florecimento precoce verificou-se o número de dias para a primeira antese. Em relação à termoinibição de sementes avaliou-se a primeira e última contagem de germinação e o índice de velocidade de germinação, utilizando-se as temperaturas de 20, 25, 30 e 35ºC. As análises foram realizadas imediatamente após a colheita e após seis meses de armazenamento. O estudo da dissimilaridade genética foi realizado por meio do método de otimização de Tocher Gráfico e hierárquico UPGMA. Os modelos de regressão foram ajustados e o agrupamento das curvas foi realizado testando a identidade dos modelos. Florescimento precoce foi observado nas cultivares Floresta, Colorado, Grand Rapids e Everglades. As cultivares apresentaram variabilidade genética e são diferentes quanto à tolerância à termoinibição. Ao agrupar as equações de regressão foi possível selecionar cultivares tolerantes à termoinibição.


Palavras-chave:     Lactuca sativa, antese, variabilidade genética, estatística multivariada, temperatura.  aALFACE  aSEMENTE  aGERMINAÇÃO  aTEMPERATURA  aSELEÇÃO  aVARIAÇÃO GENÉTICA0 01047dBrasília-DF Sociedade de Olericultura do Brasil 1983o2025-5879tHorticultura Brasileira (Brazil)x0102-0536gv. 40(1) p. 39-47; (2022)wBR2025001994  uhttps://www.scielo.br/j/hb/a/dnMKJsfrMKXkk8FxXX7SFxn/?format=pdf&lang=en