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We evaluated the role of gene flow and wild-crop introgression on the structure and genetic diversity of Lima bean ( Phaseolus lunatus ) in the Yucatan Peninsula, an important Mesoamerican diversity area for this crop, using a genotyping-by-sequencing approach (15,168 SNP markers) and two scales. At the local scale, STRUCTURE and NGSEP analyses showed predominantly crop-to-wild introgression, but also evidence of a bidirectional gene flow in the two wild-weedy-crop complexes studied (Itzinté and Dzitnup). The ABBA-BABA tests showed a higher introgression in Itzinté (the older complex) than in Dzitnup (the younger one); at the allelic level, the wild-crop introgression in Itzinté was similar in both directions, in Dzitnup it was higher from crop-to-wild; and at the chromosomal level, introgression in Itzinté was from wild-to-crop, whereas in Dzitnup it occured in the opposite direction. Also, we found H E values slightly higher in the domesticated accessions than in the wild ones, in both complexes (Itzinté: wild = 0.31, domesticated = 0.34; Dzinup: wild = 0.27, domesticated = 0.36), but % P and π estimators were higher in the wild accessions than in the domesticated ones. At a regional scale, STRUCTURE and MIGRATE showed a low gene flow, predominantly from crop-to-wild; and STRUCTURE, Neighbor-Joining and PCoA analyses indicated the existence of two wild groups and one domesticated group, with a marked genetic structure based in the existence of domesticated MI and wild MII gene pools. Also, at the regional scale, we found a higher genetic diversity in the wild accessions than in the domesticated ones, in all estimators used ( e.g. , H E = 0.27 and H E = 0.17, respectively). Our results indicate that gene flow and introgression are playing an important role at the local scale, but its consequences on the structure and genetic diversity of the Lima bean are not clearly reflected at the regional scale, where diversity patterns between wild and domesticated populations could be reflecting historical events.

Plant-insect interactions are a determining factor for sustainable crop production. Although plants can resist or tolerate herbivorous insects to varying degrees, even with the use of pesticides, insects can reduce plant net productivity by as much as 20%, so sustainable strategies for pest control with less dependence on chemicals are needed. Selecting plants with optimal resistance and photosynthetic traits can help minimize damage and maintain productivity. Here, 27 landrace accessions of lima beans, Phaseolus lunatus L., from the Yucatan Peninsula were evaluated in the field for morphological resistance traits, photosynthetic characteristics, insect damage and seed yield. Variation was found in physical leaf traits (number, area, and dry mass of leaves; trichome density, specific leaf thickness and hardness) and in physiological traits (photosynthetic rate, stomatal conductance, intercellular carbon, water-use efficiency, and transpiration). Five accessions (JMC1325, JMC1288, JMC1339, JMC1208 and JMC1264) had the lowest index for cumulative damage with the highest seed yield, although RDA analysis uncovered two accessions (JMC1339, JMC1288) with strong positive association of seed yield and the cumulative damage index with leaf production, specific leaf area (SLA) and total leaf area. Leaf traits, including SLA and total leaf area are important drivers for optimizing seed yield. This study identified 12 important morphological and physiological leaf traits for selecting landrace accessions of P. lunatus for high yields (regardless of damage level) to achieve sustainable, environmentally safe crop production.

Capsicum annuum L. var. glabriusculum is a semi-domesticated species of economic importance; however, its establishment in commercial plantations has been hampered by the low germination and emergence rates of its seeds. The aim of this study was to evaluate the effect of the fruit ripening stage on seed germination and seedling emergence in C. annuum var. glabriusculum. Seeds were extracted from fruits with six different ripening stages. The evaluated traits were the germination and emergence percentages, germination and emergence rates, and 17 physical traits of the seeds. According to the results, seeds extracted from red, orange, and pinto fruits presented better germination and seedling emergence percentages (85, 86, and 82% and 95, 93, and 94%, respectively). A principal component analysis showed that some differences in the physical traits of the seed were associated with the fruit ripening stages and seed development. A canonical discriminant analysis showed a high correlation between the fruit ripening stages and the physical and physiological characteristics of the seed, allowing the formation of four groups. The fruit ripening stages (pinto, orange, and red) influence the germination of the seeds and the emergence of the seedlings of C. annuum L. var. glabriusculum, so obtaining seeds from physiologically ripe fruits allows for obtaining seeds of better quality.

Molecular variability of vanilla (Vanilla planifolia) and three wild species was assessed to explore the possible sources of variation that can be used for crop improvement. A total of 154 ISSR loci were analysed by the UPGMA, assignment tests of individuals (STRUCTURE) and indices of genetic diversity. The assignment tests were done at two levels: first considering the four species and then only the accessions of V. planifolia. The molecular analysis indicated 99.3% polymorphism among all species and 70.45% within V. planifolia. The UPGMA showed the separation of these four species into three groups and grouped V. planifolia accessions into three subgroups. The more genetically differentiated accessions were of the Rayada morphotype and a wild accession was from Oaxaca, followed by a wild accession from Quintana Roo; all the commercial accessions of V. planifolia (Mansa morphotype) were grouped together. The STRUCTURE analysis differentiated between V. planifolia and the three wild species, and among the accessions of the Mansa and Rayada morphotypes and the wild accessions. The STRUCTURE analysis also indicated the presence of mixed individuals. These results are of great importance since the accessions of V. planifolia that are genetically more differentiated are the most threatened due to the scarcity of these individuals, the destruction of habitat and replacement by the commercial morphotype. These individuals should be salvaged and used to expand the genetic background of vanilla.

Lima bean ( Phaseolus lunatus L.) is composed of two major gene pools. The Andean gene pool gave rise to the Gran Lima cultigroup, and the Mesoamerican gene pool gave rise to the Papa and Sieva cultigroups. In the Yucatan Peninsula, Lima bean presents a great diversity of landraces that belong to the Mesoamerican gene pool. However, studies so far have not been able to determine whether the Papa and Sieva cultigroup germplasm resources managed by Maya farmers can be morphologically or genetically differentiated. In addition, the physiological seed quality traits of P. lunatus are still unknown. Therefore, the objectives of the study were: (1) To evaluate morphological differentiation of the Papa and Sieva cultigroups of Lima bean and (2) To evaluate the physiological seed quality based on standard germination and emergence of seedlings tests. Results showed two well-defined groups. Group A comprised landraces JMC1288, JMC1336, JMC1364 and JMC1271 belonging to the Sieva cultigroup; group B included landraces JMC1208, JMC1264, JMC1313 and JMC1337 belonging to the Papa cultigroup. The germination percentage was 84%, and rate was 15 seeds germinated d −1 . The percentage of seedling emergence was 86%, and seedling emergence rate was 14 emerged seedlings d −1 . Results confirmed the presence of the Papa and Sieva cultigroups in the Yucatan Peninsula. The landraces of Papa cultigroup produced seeds with the best physiological quality for use in breeding and conservation programmes.

In the search for environmentally friendly options to manage plant pests and enhance productivity with fewer external inputs in agriculture, the screening of landraces has gained importance. The aims of this study were to characterize functional leaf traits in maize landraces, including morphological traits such as leaf toughness, thickness, specific leaf area (SLA), and number of trichomes, as well as physiological leaf traits such as photosynthesis, transpiration rate, and stomatal conductance. We aimed to determine the association of these traits with leaf damage caused by Spodoptera frugiperda across 24 maize landraces. Relationships of dependence among leaf traits and leaf damage were determined using principal component analysis, multiple regression analysis and sequential path analyses. All morphological leaf traits showed differences among maize landraces mainly at 20 and 30 days after emerge (DAE) whereas at 40 DAE the differences decreased. By the contrast, physiological leaf traits had high variation at 40 DAE among maize landraces. We found a negative dependency of principal component conformed by photosynthesis, transpiration rate, and stomatal conductance over leaf damage. Based on the level of leaf damage, we categorized maize landraces into two groups with low and high susceptibility. Surprisingly, we observed that in the former group, physiological leaf traits affected the number of trichomes, whereas in the latter group, they influenced leaf thickness. This finding highlights the necessity of detailed assessments of foliage properties to understand the impact of S. frugiperda infestations. Such an analytical approach is crucial in scientific research, providing deeper insights into the underlying mechanisms of interaction between the pest and its host plants.