Polymer coating of zucchini seeds is a method to enhance seed performance during germination and emergence in the field and protect the seed from infection with diseases and insects. Experiments were conducted to identify the best method for polymer coating squash seed to improve seed germination and performance. In the first experiment, seeds were subjected to concentrations and durations of coating polymer (Discoshine Veg Red L-524 polymer) in combination with Gaucho® insecticide (Imidacloprid): 50% polymer for 40 s; 25% polymer for 40 s; 12.5% polymer for 40 s; 6.2% polymer for 40 s; 25% polymer for 40 s+10% Gaucho® insecticide, untreated seed as control. In the second experiment, seeds were exposed to different concentrations and durations. A standard germination test was run in the laboratory and seedling emergence percent and speed of emergence in a nursery. The results indicated that the best treatment was coating the seeds with 20-25% polymer for 40 s in combination with 4% Gaucho® insecticide, which had germination and seedling emergence above 90% and did not differ significantly from the control. In conclusion, thin-film coating treatments effectively delivered the insecticide safely without hurting seed germination and seedling emergence at the nursery.

Activation of γ-aminobutyric acid (GABA) shunt pathway and upregulation of dehydrins are involved in metabolic homeostasis and protective mechanisms against drought stress. Seed germination percentage, seedling growth, levels of GABA, alanine, glutamate, malondialdehyde (MDA), and the expression of glutamate decarboxylase (GAD) and dehydrin (dhn and wcor) genes were examined in post-germination and seedlings of four durum wheat (Triticum durum L.) cultivars in response to water holding capacity levels (80%, 50%, and 20%). Data showed a significant decrease in seed germination percentage, seedling length, fresh and dry weight, and water content as water holding capacity level was decreased. Levels of GABA, alanine, glutamate, and MDA were significantly increased with a negative correlation in post-germination and seedling stages as water holding capacity level was decreased. Prolonged exposure to drought stress increased the GAD expression that activated GABA shunt pathway especially at seedlings growth stage to maintain carbon/nitrogen balance, amino acids and carbohydrates metabolism, and plant growth regulation under drought stress. The mRNA transcripts of dhn and wcor significantly increased as water availability decreased in all wheat cultivars during the post-germination stage presumably to enhance plant tolerance to drought stress by cell membrane protection, cryoprotection of enzymes, and prevention of reactive oxygen species (ROS) accumulation. This study showed that the four durum wheat cultivars responded differently to drought stress especially during the seedling growth stage which might be connected with ROS scavenging systems and the activation of antioxidant enzymes that were associated with activation of GABA shunt pathway and the production of GABA in durum seedlings.

Salinity is one of the main factors in reducing crop output due to poor plant growth. According to scientists, salinity affect the growth of crops in two ways: through the osmotic effect, which reduces the plants’ ability to absorb water and retard growth; and through ionic toxicity, which means that salts can enter the perspiration system and damage the leaf cells, resulting in a diminution in cell division and cell expansion. In cultivated areas, saline soils are universal in many parts of the world, particularly in West and Central Asia and Australia. In this chapter, we will address the following points: (i) the origins of soil salinity; (ii) the effects of salinity and sodicity on soil properties [soil chemical properties and physical and hydraulic properties]; and (iii) tolerance to saline stress by the growth of plants favoring rhizobacteria (PGPR) (IV) salinity management practices.