Genetic diversity and selection in tomato genotypes under water stress induced by mannitol

Abstract

ABSTRACT:The tomato crop adapts to different climatic conditions. However, the water stress, which is a relevant factor in the tomato cropping, can affect the productivity. This experiment aimed to estimate the genetic variability, after two backcrosses, and select tomato genotypes that are tolerant to water stress induced by mannitol. The advance of the generations was done on the field and the water stress test was done in laboratory atmosphere, in a completely randomized design with four replications. 17 genotypes, in the generation F 2 BC 2 , which were obtained from an interespecific cross between Solanum pennellii and Solanum lycopersicum L. and three check treatments, one resistant [wild access LA-716 (Solanum pennellii)] and two susceptible (cv. Santa Clara and UFU-650), were evaluated. After subjected to the osmotic potential of -0.3 Mpa, the seeds were evaluated for: germination percentage, standard germination percentage, first counting percentage, germination velocity index, average time of germination and initial and final length of radicle. As expected, the wild access, S. pennellii, was better than the susceptible check treatments. The genotype UFU102/F 2 BC 2 #71115 highlighted, compared to the others F 2 BC 2 genotypes and in relation to the three check treatments, susceptible (cv. Santa Clara and UFU-650) and resistant (S. pennellii). Analyzing the genetic diversity, 8 different groups were obtained, being an indicative of genetic variability between the evaluated genotypes. The variable %G contributed with 33.9% in the diversification of the genotypes, presenting as the most important criterion, to be evaluated in genetic diversity studies, in the tomato crop under water stress, induced by mannitol.

Determination of Resistance Levels to Clavibacter michiganensis subsp. michiganensis in Some Solanum Species

“…pennellii LA716 is another valuable genetic source conferring tolerance to various biotic and abiotic stresses. For example, it is tolerant to abiotic stresses such as salt (Frary et al, 2010;Li et al, 2010) and drought (Borba et al, 2017), Moreover, LA716 showed high resistance to the obligate parasitic plants (Orobanche aegyptiaca) (El-Halmouch et al, 2006) and Phelipanche aegyptiaca (Bai et al, 2020). While previous work indicated that LA716 has resistance to different biotic stresses such as whitefly (Bemisia tabaci) (Baldin et al, 2005;Oriani and Vendramim, 2010); tomato miner, Tuta absoluta (Bitew, 2018); a bacterial spot disease caused by Xanthomonas campestris pv.…”

Research Report Genetic gain according to different selection criteria for agronomic characters in advanced tomato lines

“…Overall, performance per se is one of the main standards applied in the selection of superior tomato genotypes. For that matter, the univariate analysis using the Scott-Knott test of means (Scott and Knott, 1974) has been widely used by several authors (Araújo et al, 2016;Borba et al, 2017;Finzi et al, 2017;Maciel et al, 2018;Peixoto et al, 2018). Nevertheless, it is known that this type of selection can be inefficient, because it leads to a superior genotype in no more than one characteristic.…”