Analyses of germination of seeds under artificial stress conditions are tools for a better understanding of the survival and adaptation capacity of species under natural stress conditions. Therefore, the aim of this study was to evaluate the effect of priming on seed germination, on breaking of dormancy, and on the length of Urochloa brizantha seedlings under water restriction and salt stress conditions. A completely randomized experimental design was used with four replications in a 3 × 6 factorial arrangement consisting of 3 germination conditions (water, water restriction with PEG, and salinity with NaCl) and 6 treatments [five priming solutions (distilled water, potassium nitrate, spermidine, gibberellin, and sodium nitroprusside) and a control (unprimed seeds)]. The following determinations were made: seed moisture content after priming (before drying) and after drying the seeds, germination test at seven and twenty-one days after sowing, germination speed index, viability by the tetrazolium test of the seeds remaining from the germination test, and seedling length. Priming is effective in minimizing the negative effects of water restriction and salinity. Use of sodium nitroprusside as a priming solution results in a lower percentage of dormant seeds and greater germination, vigor, and plant development.

In comparison to tomato plants without the dwarfism gene, dwarf tomato plants were shorter, had a smaller canopy diameter and remained upright during maturation, thereby reducing the fruit-soil contact, resulting in healthier fruits. This study evaluated tomato families of a BC 1 F 3 population carrying the dwarf gene for industrial yield. The 150 BC 1 F 3 families and the two parents (hybrid H-9889 and accession BGH-9889) as controls were assessed in an augmented block design with four replications. The data were subjected to variance analysis and the F test. A selection index, based on the sum of ranks of Mulamba and Mock (1978), was used for the selection of genotypes, considering the most relevant traits, i.e., canopy diameter, yield, lodging and fruit firmness. Thus, selection resulted in a yield gain of 8.04%.

Lettuce seeds usually show germination problems that can be related to dormancy and or thermoinhibition, as well as to the genotype constitution. The knowledge of the temperature at which the thermoinhibition process begins, as well as the influence of the age of the seed on its germination, is extremely important to establish more suitable parameters for the selection of higher genotypes in breeding programs. The objective of this work was to evaluate the seed germination of three lettuce cultivars according to the enviromental temperature and the age of the seeds. The cultivars Everglades (tolerant to thermoinhibition), Luisa (medium tolerant) and Verônica (sensitive) were used. Seeds of each cultivar were evaluated by the standard germination test, first count test, germination speed index and germination test of remaining seeds. The analyses were performed at four environmental temperatures and in seven storage periods after harvest. None of the cultivars showed primary dormancy. The tolerance to thermoinhibition showed by cultivars Everglades and Luisa and the sensitivity of cultivar Verônica were confirmed. The most suitable temperature for differentiating tolerant and sensitive thermoinhibition genotypes occurred from 30.5 ºC and 260 days after harvest.

Once “bode” pepper plants (Capsicum) have continuous development and fructification, it is not possible to determine a specific season for seed physiologic maturation and harvest. This research aimed to evaluate physiological quality of “bode” pepper (Capsicum chinense 'Adjuma’) during fruit development and enzymes expression on seed germination. Manually extracted seeds were submitted to physiological tests being evaluated germination at first count (FC), final (G), and germination speed index (GSI), additionally, enzymatic analyses were carried. The lowest values for the physiological tests were observed for initial development stages. The greatest for FC, G and IVG were observed for seeds from fruits 70 days after anthesis (DAA). Superoxide dismutase enzyme has the highest values on seeds harvested at 49 DAA while malate dehydrogenase has more expression at 70 DAA. Catalase, alcohol dehydrogenase, and esterase have the higher expression at 63 DAA. The maturation stage influences bode pepper seed physiological quality, being seeds harvested at 70 DAA those with the better results on the evaluated parameters, thus, considered physiologically mature and the indicated time for harvest.

The objective of this work was to assess the genetic control of tolerance to thermoinhibition in lettuce (Lactuca sativa) seeds. Seeds of the F1, F2, and F2:3 generations derived from the cross between cultivars Everglades (tolerant to thermoinhibition) and Verônica (sensitive to thermoinhibition) were used, besides seeds from the parents. Seed germination tests were conducted in a completely randomized design, with four replicates of each parent, eight of F1, and four of each of the 26 F2:3 progenies. The mean of the F2 population was considered as the mean of the sample of the 26 progenies. The genetic control of thermoinhibition tolerance in lettuce seeds is attributed to one or a few genes. The additive effects are more expressive than the nonadditive ones, and narrow-sense heritability is relatively high, allowing the prediction of success in selection.