Weeds are one of the most damaging biotic stresses in crop production, and drought and salinity are considered the most serious abiotic stresses. These factors harmfully affect growth and development in several vegetable and field crops by causing harmful effects on physiological and biochemical characteristics such as water uptake, photosynthesis, relative water content, electrolyte leakage, and antioxidant compounds linked with oxidative stress and the accumulation of reactive oxygen species (ROS). These oxidative stress-related components affect most physiological and biochemical characteristics in plants under natural conditions and environmental stresses, especially weed infestation, salinity, and drought stress. ROS such as superoxide (O₂^•−), hydrogen peroxide (H₂O₂), peroxyl radical (ROO^•), and singlet oxygen (1O₂) are very important molecules produced naturally as by-products of metabolic processes in chloroplasts, mitochondria, peroxisomes, and the apoplast. Under stress conditions such as weed infestation, drought and salinity, the morphological and yield characteristics of stressed plants are negatively affected; however, superoxide (O₂^•−) and hydrogen peroxide (H₂O₂) are significantly increased. The negative impact of weeds can be mitigated with integrated controls which include herbicides, allelopathy, and crop rotation as well as the different methods for weed control. The defense system in various crops mainly depends on both enzymatic and nonenzymatic antioxidants. The enzymatic antioxidants include superoxide dismutase, glutathione reductase, and catalase; nonenzymatic antioxidants include ascorbic acid, carotenoids, α-Tocopherols, proline, glutathione, phenolics, and flavonoids. These antioxidant components can scavenge various ROS under several stresses, particularly weeds, drought and salinity. In this review, our objective is to shed light on integrated weeds management and plant tolerance to salinity and drought stresses associated with the ROS and the induction of antioxidant components to increase plant growth and yield in the vegetable and field crops.

The impact of proline, methionine, and melatonin on cauliflower plants under drought stress is still unclear in the available publications. So, this research aims to study these biochemical compounds’ effects on cauliflower plants grown under well-irrigated and drought-stressed conditions. The obtained results showed that under drought-stressed conditions, foliar application of proline, methionine, and melatonin significantly (p ≤ 0.05) enhanced leaf area, leaf chlorophyll content, leaf relative water content (RWC), vitamin C, proline, total soluble sugar, reducing sugar, and non-reducing sugar compared to the untreated plants. These treatments also significantly increased curd height, curd diameter, curd freshness, and dry matter compared to untreated plants. Conversely, the phenolic-related enzymes including polyphenol oxidase (PPO), peroxidase (POD), and phenylalanine ammonia-lyase (PAL) were significantly reduced compared to the untreated plants. A similar trend was observed in glucosinolates, abscisic acid (ABA), malondialdehyde (MDA), and total phenols. Eventually, it can be concluded that the foliar application of proline, methionine, and melatonin can be considered a proper strategy for enhancing the growth performance and productivity of cauliflower grown under drought-stressed conditions.

Table grape berries are classified as a perishable crop that deteriorates quickly after harvest. The application of melatonin after harvest was found to be effective for retarding senescence and slowing ripening. In the current study, we tested the influence of two melatonin concentrations (50 and 100 µmol) as a postharvest application on quality, bioactive compounds, and enzyme activities of grape berries cv “Crimson” stored at 0 ± 1 °C and 90% relative humidity (RH) for 35 days. Our results indicated that melatonin application extends the shelf-life of berries by reducing weight loss and maintaining total soluble solids (TSS), titratable acidity (TA), berry adherence strength, and firmness. Melatonin treatment also reduced pectin methyl esterase (PME) and polygalactouranase (PG) enzyme activities compared to the control. Moreover, O₂^•− and H₂O₂ rates in berries were reduced by high melatonin concentration. Moreover, peroxidase (POD) and catalase (CAT) enzyme activities were increased by melatonin application. Our findings suggested using melatonin postharvest to increase shelf life and maintain quality attributes during refrigerated storage, which could be advantageous on a large scale.

Exploration of and understanding diversity and variability in genotypes of germplasm determines the success of rice improvement programs. One of the most important determinants of the success of breeding programs is genetic diversity and inheritance of traits. Genetic variability analysis helps breeders to determine the appropriate selection method and standards to be used to improve the preferred trait. The aim of this study was to estimate genetic components, heritability and to obtain information about genetic diversity using cluster analysis and principal component analysis. Twenty rice genotypes with three replicates in a randomized complete block design were analyzed at the Experimental Farm at Sakha Agricultural Research Station, Sakha, Kafr El-Sheikh, Egypt, during the period from 2017 to 2020. The results of the analysis of variance showed that highly significant variations were recorded between the studied genotypes for all traits. The genotypic coefficient of variation (GCV%) and phenotypic (PCV%) coefficient of variation were moderate for plant height, panicles/plant, panicle weight, spikelets/panicle, filled grains/panicle, grain yield/plant and amylose content percentage for the first-year, second-year and combined data. This indicates the existence of beneficial genetic variability that can be exploited to improve these traits. The broad-sense estimates of heritability were high and recorded values higher than 60% for all the studied traits for the two-year and combined data, except for hulling percentage. This indicates that the selection of traits that have high heritability and are less affected by the environment leads to an acceleration of the improvement of these traits. The results from the cluster analysis and principal component analysis revealed a high level of genotypic variation among the studied genotypes and genetic diversity between them. One of the most important outcomes of this study is the successful utilization of genetic resources (germplasm) from ancient varieties and lines of rice in selecting and identifying 17 new restoration lines of rice, which have various improvement purposes in rice and hybrid rice breeding programs.

One filed experiment was carried out to study the effect of Arbuscular Mycorrhiza fungi and three preceding winter crops, i.e., Meskawy cultivar of Egyptian clover berseem (Trifolium alexandrinum L.), Careem cultivar of sugar beet (Beta vulgaris) and Sakha 94 cultivar of wheat (Triticum aestivum) and five fertilizer combinations as treatments of NPK mineral and bio fertilizer which included 100% NPK (T1), 75% NPK + arbuscular mycorrhiza fungi (AMFs) (T2), 50% NPK + arbuscular mycorrhiza fungi (AMFs) (T3), 75% NPK + mycrobein (T4) and 50% NPK + mycrobein (T5) on maize intercropping with cowpea. The results showed that berseem was the best as a preceding crop and gave the highest values of maize and cowpea, followed by sugar beet as a preceding crop. While wheat recorded the lowest values. Fertilizer treatments had significant effect on all maize and cowpea traits. The treatment 75% NPK + arbuscular mycorrhiza fungi (AMFs) (T2) gave the highest values. Meanwhile, no significant differences were found between fertilizer treatments T1 (100% NPK mineral) and T2 (75% NPK + arbuscular mycorrhiza fungi (AMFs)) combination on all studied characters of maize. The interaction had a significant effect on most studied characters of maize and cowpea in the two growing seasons. The cultivation of the two components of intercropping after berseem with T2 fertilizer recorded the highest values. Mixing the third cut of cowpea with maize straw increased significantly the quality and digestibility of forge in both seasons. Planting after berseem and T2 fertilizer gave the highest values as yield advantageous for land equivalent ratio (LER) and relative crowding coefficient (K) which recorded 1.51 and 1.6 and 9.45 and 15.35 in the first and second seasons, respectively. The increases in net return were 3955.67 and 5062.50 L.E., which equates to a percentage of 34.25 and 44.71%, by cultivation intercropping component after berseem and T2 fertilizer treatment (75% NPK + arbuscular mycorrhiza fungi (AMFs)) compared with maize pure stand in first and second seasons, respectively.