RESUMOO experimento foi conduzido com o objetivo avaliar as características morfofisiológicas do tomateiro quando submetido a diferentes níveis de déficit hídrico e, com base nesses resultados, indicar os melhores caracteres para seleção de plantas com maior resistência ao déficit hídrico. O delineamento experimental foi em blocos casualizados, com quatro repetições, no esquema de parcelas subdivididas, em que os tratamentos principais (parcelas) foram constituídos por duas linhagens (TOM-684 e M-82) e as subparcelas por quatro níveis de umidade do solo (100 %, 75 %, 50 % e 25 % da capacidade de campo). Foram avaliados os seguintes caracteres: produção de frutos, massa fresca e seca das folhas, caule e sistema radicular, diâmetro do caule, altura das plantas, número de folhas, fotossíntese, transpiração, temperatura foliar, umidade intercelular, dióxido de carbono intercelular, condutância estomática, condutância de CO 2 intercelular e condutância total. Com a redução da umidade do solo houve redução do número de folhas, altura das plantas, massa fresca e seca das folhas, caule e sistema radicular, transpiração, taxa fotossintética, produção de frutos e aumento da temperatura foliar. A condutância estomática diferiu entre as duas linhagens, com maiores valores para a cultivar TOM-684, que reduziu a condutância estomática de 0,70 para 0,25 mol m -2 s -1 entre os níveis de 100 e 25 % da capacidade de campo. A altura das plantas e o número de folhas podem ser utilizadas em programas de melhoramento como ferramenta para seleção de plantas com maior resistência ao déficit hídrico.Palavras-chave: Solanum lycopersicum; Tolerância a seca; Déficit hídrico; Eficiência do uso da água. ABSTRACTThe experiment was conducted to evaluate the morphological/physiological characteristics of tomato plants when submitted to different levels of water deficit and, based on these results, indicate the best characters for the selection of plants with more tolerance to water deficit. The experimental delineation was in randomized complete block design, with four replications, arranged in splitplot, in which the main treatments (plots) were composed by two strains (TOM-684 and M-82) and the subplots, by four levels of soil moisture (100 %, 75 %, 50 % and 25 % of the field capacity). The following parameters were evaluated: fruit production, leaf, stem and root system fresh and dry mass, , stem diameter, plant height, number of leaves, photosynthesis, transpiration, foliar temperature, intracellular moisture, intracellular carbon dioxide, stomatal conductance, conductance of intracellular CO 2 and total conductance. With the reduction of soil moisture occurred reduction in the number of leaves, plant height and leaf, stem and root system fresh and dry mass, transpiration, photosynthetic rate, fruit production and increase of foliar temperature The stomatal conductance differed between both strains, with higher values for the TOM-684 strain, which reduced stomatal conductance from 0,70 to 0,25 mol m -2 s -1 between levels of 100 and 25 % of...

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Environmental stress, such as drought stress, constantly cause production loss. Breeding programs search for genotypes which may overcome climate adversities, producing in ideal as well as in stressful environments. The present work aimed at to evaluate parameters related to water deficit in 20 F 3 RC 1 families of tomato plants derived from the crossing with a (WELL) genotype, originated from a drought resistant species, as well as select plants using characters related to water deficit resistance. The delineation was in randomized blocks design with three replications. Two experiments were carried out, the first in Lavras, Minas Gerais state, Brazil, that consisted in evaluating nine F 3 RC 1 families derived from two self-fertilizations of the following crosses: {TOM-684 x (WELL x M-82)}. The second experiment was carried out in Ijaci, in the same state, and evaluated the same nine families from the previous experiment and another eleven families obtained from the same crossing. The plants were submitted to water deficit by means of the suspension of irrigation at 35 days after transplanting the seedlings to the field. The families T4, T5, T6, T15, T17 were highlighted regarding fruit production and, among the nine families evaluated in both cultivation environments, the T6 was the most productive, indicating good productive stability. Families T5 and T9 were highlighted for presenting low incidence of blossom-end rot and higher relative water content in leaves. The blossom-end rot incidence and relative water content are good parameter to be indirect selection of plants more resistant to drought.