The European Union is promoting regulatory changes to ban fungicides because of the impact their use has on the ecosystem and the adverse effects they can pose for humans. An ecofriendly alternative to these chemicals to fight against fungal species with low toxicity is essential oils and their compounds extracted from aromatic plants. The purpose of this study was to evaluate the in vitro antifungal capacity of the botanical compounds eugenol, carvacrol, thymol, and cinnamaldehyde, and the synergy or antagonism of their mixtures, against Botryotinia fuckeliana and Rhizoctonia solani. Different bioassays were performed at doses of 300, 200, 150, and 100 µg/mL using pure commercial compounds and their combination in potato dextrose agar culture medium. Growth rate and the mycelium growth inhibition parameters were calculated. Phenolic compounds and their combination inhibited the development of species at the different concentrations, with fungicidal or fungistatic activity shown under almost all the tested conditions. When comparing the growth rates of the species in the control plates and treatments, the statistical analysis showed that there were statistically significant differences. The mixture of compounds improved fungicidal activity against the studied species and at a lower concentration of monoterpenes.
Agriculture will face many challenges regarding food security and sustainability. Improving phosphorus use efficiency is of paramount importance to face the needs of a growing population while decreasing the toll on the environment. Pepper (Capsicum spp.) is widely cultivated around the world; hence, any breakthrough in this field would have a major impact in agricultural systems. Herein, the response to phosphorus low-input conditions is reported for 25 pepper accessions regarding phosphorus use efficiency, biomass and root traits. Results suggest a differential response from different plant organs to phosphorus starvation. Roots presented the lowest phosphorus levels, possibly due to mobilizations towards above-ground organs. Accessions showed a wide range of variability regarding efficiency parameters, offering the possibility of selecting materials for different inputs. Accessions bol_144 and fra_DLL showed an interesting phosphorus efficiency ratio under low-input conditions, whereas mex_scm and sp_piq showed high phosphorus uptake efficiency and mex_pas and sp_bola the highest values for phosphorus use efficiency. Phosphorus low-input conditions favored root instead of aerial growth, enabling increases of root total length, proportion of root length dedicated to fine roots and root specific length while decreasing roots’ average diameter. Positive correlation was found between fine roots and phosphorus efficiency parameters, reinforcing the importance of this adaptation to biomass yield under low-input conditions. This work provides relevant first insights into pepper’s response to phosphorus low-input conditions.
After harvesting rice paddy fields, rice straw is a significant problem due to uncontrolled CO2 emissions when the straw is burned. One solution to this problem is to use this rice by-product for mulching planting lines of fruit trees or vineyards with the purpose of controlling weeds and improving soil characteristics. A 3-year experiment was conducted at the Polytechnic University of Valencia (Spain) demonstration vineyard, where rice-straw mulch was installed at three rates in 2021, 24.0, 43.1, and 63.1 t ha−1, and in 2022, 25.0, 37.5, and 50.0 t ha−1. Weeds were mainly controlled with the highest treatment rate (50.0–63.1 t ha−1), as the time of the year for mulch installation is decisive for achieving different weed control rates. On average, mulch decreased soil bulk density (5.4%), and increased the soil organic carbon (24.3%) and water-soluble organic carbon (24.3%) compared to bare soil. Soil temperature changes were observed due to the mulch treatment, with soil temperature lower in bare soil than in mulched soil during the cold season, and higher during the warm season. This effect was highly dependent on the mulch application rate. Soil moisture content was also higher under the mulch treatment, showing a mulch-rate response during the four seasons of the year. The changes in the physical and biological soil properties induced a higher soil respiration rate when mulched soil was compared to bare soil. This study concludes that the use of rice straw as a mulch had positive effects on weed control and soil properties, although three factors concerning mulch management were paramount: rate, the timing of installation, and replacement rate.
19 June 2024 in Notulae Botanicae Horti Agrobotanici Cluj-Napoca
Fertilization is essential for maintaining production in agriculture. Yet, in too high quantity it causes high impact in environment and in farmers economy. This is especially true in the case of phosphorus (P) fertilization. Finding genotypes adapted to low P conditions may help to reduce the problem. P efficiency depends to some extend on the ability of the roots to acquire this mineral, therefore using efficient rootstocks would provide a higher acquisition of P, maintaining the good characteristics of the scion varieties. In this study, twenty diverse pepper accessions (Capsicum annuum L.) have been evaluated as possible rootstocks to increase P acquisition and yield in pepper under no P fertilization. Plant production, biomass, P content and physiological phosphorous use efficiency were evaluated for ‘Lobo’ variety grafted onto different rootstocks. In addition, root traits, measured manually (shovelomics) and semi-automatically (Winrhizo) were studied. The results showed a great diversity in the root traits for the studied accessions. These root traits changed significantly when the accessions act as rootstock, indicating great rootstock/scion interactions. In general, all the rootstocks adapted their root size and shape to that displayed by ‘Lobo’ root system. Some accessions seemed to have some incompatibility whereas some others enhanced the scion performance. It was possible to identify some genotypes suitable to act as rootstocks for pepper with good performance under low P conditions. Root length, root weight, branching, and root angle were identified as key root traits for plant growth and P acquisition under low P conditions.
Modern Solanum melongena varieties have been developed to improve the content of phenolics, sugars, and nutritionally relevant minerals in fruit. However, fruit composition might be altered due to abiotic stresses like salinity. Physiological and fruit quality traits were evaluated in four eggplant landraces under usual irrigation and moderately salty irrigation conditions (80 mM NaCl). Growing parameters measured included root length, leaf surface, and fresh weight, while fruit composition traits included sugars, phenolics, and mineral content determinations. Few differences were observed for agronomic traits, probably due to the mild tolerance of eggplant to salinity. Some varieties showed signs of salt tolerance like an increase in primary root length to overcome salt stress. Glucose was the metabolite more affected by the salt treatment in the fruit, while phenolic compounds and other metabolites studied were not altered. Significant differences were observed in the main minerals Na, K, Ca, P, and Mg, both between genotypes and treatments. Although salinity produced changes in some physiological and developmental traits, the composition of the fruit was not significantly modified for the accessions tested. Mineral, sugar, and phenolic contents were not particularly altered in unripe fruits, indicating tolerance of eggplant varieties to salinity in terms of fruit quality.