Identification of novel genotypes with enhanced nitrogen use efficiency (NUE) is a key challenge for a sustainable tomato production. In this respect, the performance of a panel of thirty tomato accessions were evaluated under high (HN; 5 mM N) and low (LN; 0.5 mM N) nitrogen irrigation solutions. For each treatment, when 50% of plants reached the first flower bud stage, plant growth and biomass traits, chlorophyll, flavonol and anthocyanin indexes, nitrogen balance index (NBI), C:N ratio in leaves, stems, and roots, and NUE were evaluated. Significant (p < 0.05) effects were observed for accession, N treatment, and their interaction across all the traits. Under LN, plants showed a delayed development (40 days for HN vs. 65 days for LN) and reduced growth and biomass. On average, LN condition led to 41.8% decrease in nitrogen uptake efficiency (NUpE) but also 189.0% increase in NUtE, resulting in 62.2% overall increase in NUE. A broad range of variation among accessions was observed under both HN and LN conditions. Under LN conditions, chlorophyll index and NBI decreased, while flavonol and anthocyanin indexes increased. Leaf C:N ratio was positively correlated with nitrogen utilisation efficiency (NUtE) in both N treatments. Multi-trait analyses identified top-performing accessions under each condition, allowing to identify one accession among top performers under both conditions. Correlation analysis revealed that high root biomass and leaf C:N ratio are useful markers for selecting high NUE accessions. These findings offer valuable insights for improving tomato NUE under varying nitrogen fertilization conditions and for breeding high-NUE cultivars.

Asteraceae is one of the families with a large number of ornamental plants. Climate change imposes the need to select species that are more tolerant to changing environmental conditions, especially drought. In this study, we compared the performance under water stress of six species belonging to different tribes of Asteraceae with different geographical origins. Young plants obtained after seed germination were subjected to intermediate water stress (irrigation with half the water amount used in control treatments) and severe water stress (no irrigation at all) for one month. Growth variables and biochemical stress markers were determined to assess the effects on the plants of the stress treatments. Multivariate analysis tools were used to rank species according to their tolerance. Three species were relatively more susceptible to water stress, Callistephus chinensis, Xerochrysum bracteatum, and Calendula officinalis, whereas Leucanthemum vulgare, Glebionis carinata, and Ageratum houstonianum were more tolerant. Our study indicated that the last two species, which are registered as invasive in some geographic areas, possess a larger phenotypic plasticity. Principal component analysis (PCA) combined with canonical variation analysis (CVA) proved optimal statistical methods for analysing species of diverse origins and belonging to different genera of a large family, such as the Asteraceae.

Background: The generation of new eggplant (Solanum melongena L.) cultivars with drought tolerance is a main challenge in the current context of climate change. In this study, the eight parents (seven of S. melongena and one of the wild relative S. incanum L.) of the first eggplant MAGIC (Multiparent Advanced Generation Intercrossing) population, together with four F₁ hybrids amongst them, five S5 MAGIC recombinant inbred lines selected for their genetic diversity, and one commercial hybrid were evaluated in young plant stage under water stress conditions (30% field capacity; FC) and control conditions (100% FC). After a 21-day treatment period, growth and biomass traits, photosynthetic pigments, oxidative stress markers, antioxidant compounds, and proline content were evaluated. Results: Significant effects (p < 0.05) were observed for genotype, water treatments and their interaction in most of the traits analyzed. The eight MAGIC population parental genotypes displayed a wide variation in their responses to water stress, with some of them exhibiting enhanced root development and reduced foliar biomass. The commercial hybrid had greater aerial growth compared to root growth. The four F₁ hybrids among MAGIC parents differed in their performance, with some having significant positive or negative heterosis in several traits. The subset of five MAGIC lines displayed a wide diversity in their response to water stress. Conclusion: The results show that a large diversity for tolerance to drought is available among the eggplant MAGIC materials, which can contribute to developing drought-tolerant eggplant cultivars.

As access to irrigation water becomes increasingly limited, introgression of relevant genomic regions from drought-tolerant wild genotypes is a promising breeding strategy for crop plants. In this study, nine eggplant ( Solanum melongena ) introgression lines (ILs) covering altogether 71.6% of the genome of the donor wild relative parent S. incanum were evaluated for drought tolerance under water stress conditions. Plants at the five true leaves stage were irrigated at either 100% (control) or 30% (water stress) field capacity for 14 days, and growth and biochemical traits were measured. Reduced irrigation resulted in decreased growth and increased levels of stress markers such as proline and malondialdehyde. Most ILs had lower growth and biomass production than the cultivated parent under both conditions. However, the wild alleles for two QTLs related to stem and root dry weight ( dwt8 and dwr6% ) conferred improved tolerance to water stress. In addition, several S. incanum alleles had a positive effect on important traits that may improve yield under drought conditions, such as leaf water content ( lwc12% ), water use efficiency ( wue1% ) and chlorophyll content ( chl2 and chl8% ). Fine-mapping of the QTLs for tolerance and reducing linkage drag with regions affecting growth will be crucial for significantly improving eggplant drought tolerance through introgression breeding.

Horticultural crops are increasingly affected by water stress due to climate change, making the development of stress-tolerant varieties essential. In this study, we evaluated 184 multi-parent advanced generation inter-cross (MAGIC) eggplant lines under water stress conditions, consisting of irrigation at 30% of field capacity. After 21 days of stress, we assessed growth-related traits, water content, plant pigments, and proline content. The MAGIC population showed high variability for water stress tolerance, with several transgressive lines surpassing parental values. Key traits related to water stress tolerance included increased root growth and higher levels of proline and flavonoids. Genome-wide association study (GWAS) analysis identified three genomic regions linked to total dry weight, water content, and flavonoid content—traits associated with performance under water stress. Additionally, a linear genomic selection index was constructed based on total dry weight, dry weight increase during the stress period, root dry weight, water content, and proline content. This index was used to predict stress tolerance in 141 unevaluated MAGIC lines, with prediction accuracies ranging from 0.11 to 0.53. This study highlights critical traits, genomic regions, and lines with potential for breeding, providing valuable information for future efforts to improve water stress tolerance in eggplant.

Horticultural crops are increasingly affected by water stress due to climate change, making the development of stress-tolerant varieties an urgent need. In this study, we evaluated a set of 184 Multi-parent Advanced Generation Inter-Cross (MAGIC) eggplant lines under water stress conditions, consisting of irrigation at 30% of field capacity. After 21 days of stress, we assessed traits related to growth, water content, plant pigments, and proline content. The MAGIC population displayed a high variability for water stress tolerance, as transgressive lines over parental values were found for most of the traits. Key traits associated with water stress tolerance were identified, including increased root growth and elevated proline, and flavonoid content. Genome-Wide Association Study (GWAS) analysis allowed identification of three genomic regions associated with total dry weight, water content and flavonoids, traits that contribute significantly to stress tolerance. Additionally, a linear genomic selection index was constructed based on total dry weight, dry weight increase during the stress period, root dry weight, water content, and proline content to identify water stress-tolerant and susceptible lines. The model’s predictive ability was calculated, and the value of the selection index was predicted for 141 unevaluated MAGIC lines, with prediction accuracy for the index traits ranging from 0.11 to 0.53. This study presents a comprehensive analysis, identifying critical traits, genomic regions and lines with genetic potential, providing valuable information for future breeding programmes to improve water stress tolerance in eggplant.