Plant growth regulators are chemical substances which govern all the factors of development and growth within plants. The application of plant growth regulators to crops modifies hormonal balance and growth leading to increased yield, enhanced crop tolerance against abiotic stress and improved physiological trait of crops. Paclobutrazol (PBZ) [(2RS, 3RS)-1-(4-chlorophenyl)- 4, 4-dimethyl-2-(1H-1, 2, 4-trizol-1-yl)-pentan-3-ol], is one of the members of triazole family having growth regulating property. The growth regulating properties of PBZ are mediated by changes in the levels of important plant hormones including the gibberellins (GAs), abscisic acid (ABA) and cytokinins (CK). PBZ affects the isoprenoid pathway, and alters the levels of plant hormones by inhibiting gibberellin synthesis and increasing cytokinins level and consequent reduction in stem elongation. When gibberellins synthesis is inhibited, more precursors in the terpenoid pathway accumulate and that resulted in the production of abscisic acid. PBZ is more effective when applied to the growing media and application on the growing medium would give longer absorption time and more absorption of active ingredient than foliar spray. The application of PBZ to crops is important in reducing plant height to prevent lodging and in increasing number and weight of fruits per tree, in improving the fruit quality in terms of increases in carbohydrates, TSS, TSS/TA and decreases acidity. It further reduces evapo-transpiration and decreases plant moisture stress by enhancing the relative water content of leaf area and develops resistance in the plants against biotic and abiotic stresses. In addition, it acts as highly active systemic fungicide and used against several economically important fungal diseases. In this review, the current knowledge and possible applications of PBZ, which can be used to improve the growth, yield and quality of crops, have been reviewed and discussed. The role of PBZ to mitigate the harmful effects of environmental stresses in crops is also examined. Moreover, various biochemical and physiological processes leading to improved crop production under the effect of PBZ are discoursed in detail.

Mulches are materials applied in a soil surface for different roles and purposes. Plastic mulches with different colour have been developed and utilized in different crop production systems. Using coloured plastic mulches is mainly focused in modifying the radiation budget and decreasing the soil water loss. Besides, it helps to regulate soil temperature, water use efficiency, plant growth, yield, quality and weed and insect infestation. In this review, the knowledge and possible application of coloured plastic mulches, which can improve the soil physical properties, growth, yield, and quality crops has been reviewed and discussed. The role of coloured plastic mulches to mitigate the harmful effect of environmental stress in crops is also examined. Various physicochemical processes leading to improved crop production under the effect of coloured plastic mulches are also discussed. The combined results indicated that, effect of coloured plastic mulches is highly significant on soil temperature, moisture and water holding capacity. While black and blue plastics increase soil temperature, clear and white decreases it. Higher number of fruits, number of roots, tubers and bulbs was recorded in use of coloured plastic mulches. Similarly, the TSS, Vitamin C and juice percentage of different plants also showed significant improvement. It is also reported that weed infestation and viral diseases is highly reduced. Coloured plastic mulches also have some negative impacts like, decrease growth and yield in some plants, increase pest infestation, microplastics contamination, soil puddling, soil structural loss and reduce activity of soil-microorganisms. Therefore, use of coloured plastic mulches require close inspection of interaction with factors like; cropping season, root zone temperature, crop type, insect pest infestation and water use efficiency factors.

Background: Farmers are forced to store garlic bulbs for a long period due to occasional excess production or to save bulb seeds for next season planting, but the bulbs often lose their viability and vigour due to sprouting ahead of planting time. Objective: The research was conducted to evaluate the effects of three harvest stages (60, 80, and 100% top fall), two curing levels (non-cured and cured bulbs), and three storage methods (floor, shelf, and net bag) on storability of garlic variety ‘Tseday’ at Haramaya University, and Tony farm (Dire Dawa) during 2014-15. Methods: The experiment was laid out in a Randomized Complete Block Design with three replications at both sites. Results: Significant variations in the storability of bulbs were evident due to harvest stages, curing, and storage methods. Harvesting of garlic bulbs at 100% top fall considerably increased bulb yield by about 16.74% and 8.75% compared to 60 and 80% top fall, respectively. Cured bulbs showed lower fresh bulb yield as compared to non-cured bulbs. Harvesting at 80% top fall, curing and storing bulbs on a shelf or in a net bag showed reduced weight and diameter loss of bulbs as compared to the other treatments. Bulbs harvested at 80% top fall and cured had significantly higher dry matter content than the rest. The highest sprouting percentage was recorded for 60% top fall harvested and non-cured bulbs, while the least was observed in 80% top fall harvested and cured bulbs. Conclusion: The result of this study has shown that harvesting at 80% top fall, curing, and storing bulbs on a shelf or in a net bag leads to a good yield and postharvest quality and effective storability of garlic bulbs under ambient storage conditions.

Ximenia americana is one of the most valuable wild edible plants in the world. In different countries, it is utilized as food, medicine, an essential oil source, and the industrial component to other products. In Ethiopia, it was one of the most known and very important plants for a long period of time. It was utilized as food, a medicinal plant, and animal feed. It was also one of the most economically important and culturally valuable plants. But nowadays, it is not adequately available in the country due to deforestation problem in the years. In addition, its economic importance, current status, and medicinal roles are not well documented and understood. As for research studies, it is concluded that unless a collective effort is taken, the existence of this plant is under severe threat and needs to have some measures. This review article is aimed at addressing the abovelined topics in detail and to pinpoint and explain the importance and status of Ximenia americana.

Garlic is an important cash crop in many regions of Ethiopia. However, the yield of the crop is constrained by several factors. Among these, inappropriate clove size is one of the major agronomic practices that can decrease the yield of the crop. Hence, a field experiment was conducted during the 2020/21 main cropping season at Debre Berhan University, College of Agriculture and Natural Resource Sciences, demonstration and research site to evaluate the effect of clove size on growth and bulb yield of garlic (Allium sativum L.). The treatments consisted of five clove sizes: 1–1.49 g, 1.5–1.99 g, 2–2.50 g, 2.51–2.99 g, and 3–3.5 g. An improved variety “Tseday” was used as a planting material. The experiment was laid out as a randomized complete block design in a factorial arrangement and replicated for three times. The results revealed that clove size significantly influenced all growth and yield parameters of garlic. Planting of 3–3.5 g cloves reduced days to emergence by 11 and 6.33 days and days to maturity by 28.33 and 18.00 days, respectively, as compared to planting of 1–1.49 g and 2–2.5 g cloves. This treatment also increased total bulb yield by 25.88% and 15.58%, respectively, as compared to planting of 1–1.49 g and 2–2.5 g cloves. In addition, this treatment significantly increased most of the growth and bulb yield components. Hence, it can be concluded that planting of 3–3.5 g cloves could be recommended to enhance early emergence, good vegetative growth, and total bulb yield of garlic.