Drought compromises edible vegetable production worldwide, including common bean (Phaseolus vulgaris L.) an economically important crop that is highly dependent on optimum rainfall or abundant irrigation. In the present study, phenotypic data of 26 Bulgarian common bean mutant lines and cultivars subjected to drought stress has been summarized, and drought stress reaction was evaluated by chlorophyll fluorescence and proteomics approaches. Several basic photosynthetic parameters were examined during treatment to evaluate the drought stress response, and the mutant lines showed different responses. Subsequently, a relationship was found between productivity and photosynthetic performance with the expression of ribulose-1,5-bisphosphate carboxylase through comparative 2D-gel based electrophoresis; accumulation of the well-known stress-related proteins markers dehydrins and small heat shock proteins was established as well. These findings support the further selection of drought tolerant common bean lines for a sustainable agriculture.

Drought is among the stress factors that, on a global scale, have direct negative effects on plant growth, yield, and quality. Great efforts are directed towards water shortage adaptation. Exploring the genetic diversity of landraces often tolerant to locally occurring stress can represent a valuable source for the development of cultivars with yield stability and improved quality under stress conditions. This study aimed to identify drought-tolerant tomato landraces based on an integrated approach involving morphological traits and physiological parameters. To investigate the effects of water deficit, five landraces and two controls were tested under optimum and 50% reduced irrigation. Yield and yield-related traits, color, firmness, and chlorophyll fluorescence measurements were evaluated. The summarized results indicated that the tomato landraces differed in their responses to water deficit. Water deficit decreased the yield by 44% and the average fruit weight by 29%. Physiological parameters were also significantly affected by water scarcity, with a decrease in the ratios Fv/Fm (the maximum quantum yield of PSII) and Fv/Fo (the maximum primary yield of photochemistry) of 8.2% and 35.5%, respectively, at 14 days’ exposure to stress. Landrace 1352, characterized by indeterminate growth habit and large, rounded, and red-colored fruits, showed a significantly lower reduction in yield and physiological parameters under reduced irrigation and could be used in breeding programs to develop new tomato lines combining resistance with quality.

A comparative assessment of various species of the Cucurbitaceae family for water deficit was carried out at the “Maritsa” Vegetable Crops Research Institute – Plovdiv during the period 2022-2023. The aim of our study was to characterize different species of Cucurbitaceae family and evaluate them for drought tolerance at the seedling stage. In order to analyze the physiological response of cucurbit crops to drought, a vegetation experiment was carried out with the following genotypes from the Cucurbitaceae family: Lagenaria siceraria (Molina) Standl. (Long gourd): Lagenaria siceraria (Molina) Standl. (Local population) (Common gourd) Cucurbita maxima Duch. ("Plovdivska 48/4") (White pumpkin); Cucurbita moschata Duch. (Muskatna 51-17); and Luffa cylindrica Roem. (Local population). The experiment was conducted under controlled conditions in a greenhouse. Plant genotypes were grown under three contrasting levels of irrigation: optimal irrigation rate of 100% (Control); reduced irrigation rate of 50% and no irrigation for 14 days. Various screening approaches were applied, including plant growth parameters (biomass, plant height, root length, fresh weight, dry weight of plants, and leaf number; and physiological responses (chlorophyll fluorescence induction parameters and chlorophyll content index). Based on the studied biometric parameters and the analysis of chlorophyll fluorescence as well as the content of total chlorophyll in drought plants in the seedling phase, the local population of long gourd (L. siceraria) is characterized as more tolerant followed by the common gourd. Susceptibility is shown by Cucurbita moschata variety "Muskatna 51-17", followed by Cucurbita maxima "Plovdivska 48/4".