Essential Oils as Biocontrol Agents of Early and Late Blight Diseases of Tomato under Greenhouse Conditions

Tomato production worldwide is usually restrained by various infections, among them mainly the late and early blight caused by Phytophthora infestans and Alternaria solani, respectively. Lately, there has been a growing concern over the use of synthetic fungicides on environmental and food safety, hence the need to explore other alternatives that are friendly to the user, the consumer, and the general environment. This research sought to test the potency of ginger, garlic, and Mexican marigold essential oils against the early and late blight diseases of tomato under greenhouse conditions. A synthetic fungicide (Ridomil Gold®) was used as a positive control while distilled water acted as a negative control. The extraction of essential oils was done by dry steam distillation and then mixed with tween twenty before being topped up with sterile distilled water. They were then used to spray tomato plants that had been inoculated with A. solani and P. infestans isolates under greenhouse conditions. The tomato plants were evaluated for growth, yield, and disease severity. The data obtained was subjected to ANOVA and separation of means was conducted using Student–Newman–Keul (SNK) test at 95% level of confidence. The three essential oils had a significant potency against the two diseases which is comparable to the synthetic fungicide. Marigold essential oil was also found to have a significant impact on the general growth of sprayed tomato plants. Essential oils of the three plants can be further explored as alternative products management of the two diseases.

Coheritability and Genetic Advances of Agromorphological and Oil Quality Traits in Groundnut (Arachis hypogaea L.) Genotypes from Ethiopia

Groundnut (Arachis hypogaea L.) is one of the most important oils, food, confectionery, and feed crops due to its high oil quality and richness in all classes of nutrients. Coheritability helps in determining the pattern of coinheritance of two or more traits. This study was aimed at determining the coheritability of oil and yield traits to provide means of conducting improvement of oil traits through breeding for yield traits. The coheritabilities of the traits were estimated by a pooled analysis of covariance (ANCOVA) for agromorphological and oil traits. The result indicated that all oil traits have shown medium to high coheritability with oil content, oil quality, and seed yield. The coheritability and genetic advance of the three agronomically important traits in oil crops including oil content, oleic to linoleic acid (O/L) ratio, and seed yield (SY) is greater than oil content, linoleic acid, and SY can be further evidence showing that both oil content and oil quality traits can be improved with seed yield, indicating that there is the possibility of making a selection for genotypes with high oil content, oil yield, and oil quality with high seed yield traits.

Cultivation of Pleurotus ostreatus on Agricultural Wastes and Their Combination

Background. Mushrooms are increasingly becoming an important component of diets worldwide, and it is of paramount importance to choose appropriate substrates to grow them. The objective of this study was to grow Pleurotus ostreatus mushroom using different agricultural substrates. Methods. Corncobs, finger millet straw, and bamboo waste were collected from different sites of the Awi Zone. The substrates were chopped into small pieces, and 500 g of their dry mass alone and their combination was measured, packed in a polythene bag, moistened, and pasteurized. The cooled substrates were inoculated with a spoon of P. ostreatus spawn brought from Debre Berhan University. The bags were placed in the growing room, and growth parameters were recorded continuously with environmental variables. The experimental setup was a complete randomized design, six treatments with three replicates. Results. The fastest spawn running phase of P. ostreatus was 28.71 ± 0.80 days, pinhead formation was 32.36 ± 0.26 days, and fruiting bodies’ formation was 5.19 ± 0.74 days after the pinhead was recorded on the corncob substrate. The highest fresh weight and biological efficiency with the significant statistical association were obtained from P. ostreatus grown on finger millet straw (253.07 ± 1.05 and 50.20 ± 0.47, respectively). The highest average number of pinheads and fruiting bodies (29.60 and 11.44, respectively) was recorded on finger millet straw. The lowest biological efficiency (20.80 ± 0.41), fresh weight (101.48 ± 0.91), number of pinheads (14.40), and number of fruiting bodies (4.25) were recorded from a mixture of corncob and bamboo waste (50% each) substrates. Conclusion. Finger millet straw is recommended as the best substrate for the cultivation of P. ostreatus. The mixed substrate of corncob and bamboo waste (1 : 1) for P. ostreatus cultivation is not encouraged due to poor growth performance.

The Residual Effect of Pre-Rice Green Manuring on a Succeeding Wheat Crop (Triticum aestivum L.) in the Rice-Wheat Cropping System in Banke, Nepal

Rice-wheat is the most widely used cropping pattern in Nepal. This cereal-based cropping system is highly nutrient exhaustive and unsustainable from a soil management perspective. They contribute neither nitrogen nor biomass to the soil. The net effect is the export of nutrients from the soil. The unused period between wheat harvest and rice transplanting is the summer fallow, and the incorporation of green manure during this short period increases the yield of both crops and improves the soils chemical properties. Altogether, there were 9 treatments and 3 replications with the randomized complete block design (RCBD). Dhaincha, sun hemp, black gram, cowpea, mung bean, and rice bean were used as pre-rice green manure. No chemical fertilizers were used for the green manure, and in wheat, 150 : 50 : 50 NPK kg/ha was applied. Goat manure was applied at the rate of 10 t/ha. The main objective of the study is to ascertain the residual effect of pre-rice green manuring on the chemical properties of the soil and the yield attributes of the succeeding wheat crops. The chemical properties of the soil were analyzed before and after the harvesting of wheat, and the yield attributes parameters were analyzed. The result showed that the green manure-treated plots gave a significantly higher yield as compared to solely chemical fertilizers-treated plots. The maximum grain yield was obtained from black gram (5.870 t/ha). There was a 39.76% increase in the grain yield in the black gram-incorporated plots as compared to the only-chemical fertilizers-treated plots. There was a highly (<0.001) significant difference in the soil organic matter of the green manure-treated plots and the only-chemical fertilizers-treated plots. The sun hemp-incorporated plot increased the soil organic matter by 71% when compared to the only-chemical fertilizers-treated plot. There was no significant residual effect of pre-rice green manuring on the soil pH in a one-cropping season. However, there was a significantly higher residual effect of the green manure on the soil’s total nitrogen content in all green manure-treated plots. It was found to be the highest (0.087%) in pre-rice dhaincha. The overall results indicate that the incorporation of pre-rice green manuring improved the soil’s chemical properties and increased the grain yield of the succeeding wheat crops in a rice-wheat cropping system.

Mutagenesis and Identification of Sugarcane Mutants Using Survival on Polyethylene Glycol and Leaf Damage under Managed Water Stress

Drought causes severe damage to sugarcane, reducing its product yield. Given Thailand’s weather conditions and topography, a breeding program to develop new sugarcane genotypes with a high tolerance for water stress is important to the sugarcane industry. This study created new water stress tolerant sugarcane genotypes using ethyl methanesulfonate (EMS) mutagenesis in the sugarcane cultivar Khon Kaen 3. Using 16 mM of EMS for 4 h induced callus mutagenesis (survival rate, 57.5%). The survival rates of calli treated with 10 mM of EMS for 2 and 4 h in selective media with 15% PEG were higher than that of non-EMS-treated calli. The selected calli survived and grew on selective media with 20% PEG, while non-EMS-treated calli did not grow. The mutant plantlets developed from EMS-treated calli on selective media with 20% PEG for 4 weeks had varying survival rates: 72.25% (10 mM of EMS for 2 h), 75.85% (10 mM of EMS for 4 h), and 60.61% (16 mM of EMS for 4 h). Both healthy mutant sugarcane plants (2,086) and non-mutant plants (234) were cultured on the media with 20% PEG for 16 weeks. Of these, 462 mutant sugarcane plantlets survived and developed on the media, but all the non-mutant sugarcane plantlets died during the selection process. Mutagenesis induced using treatment 4 produced the highest frequency of mutant sugarcane plantlets with water-stress tolerance (45.5%). In total, 136 selected mutant sugarcane plants were transplanted to a greenhouse for evaluation under managed water stress. Fourteen mutant sugarcane plants stayed green after the third cycle of water stress, but the KK3 sugarcane cultivar showed damage on 50% of the leaves. Thus, EMS mutagenesis and evaluation using in vitro and greenhouse methods were successful in developing new sugarcane clones with high water-stress tolerance, which is important for sugarcane breeding programs.

Grain Yield and Nitrogen Uptake of Maize (Zea mays L.) as Affected by Soil Management Practices and Their Interaction on Cambisols and Chernozem

Although numerous factors contribute to wide yield gaps, low external inputs, particularly N, and poor cropping practices such as soil tillage and monocropping are among the major factors affecting low maize production. In view of this, field experiments were implemented on two sites with Cambisols and Chernozem soil types in two consecutive years to evaluate the impacts of different soil management practices on the grain yield and quality, nitrogen uptake, and selected soil properties. A three-factor experiment was arranged as a split-split plot arrangement randomized complete block design with three replications. The minimum tillage (MT) and conventional tillage (CT) were used as the main plot, haricot bean-maize rotation and maize monocropping were used as the subplot, and four levels of nitrogen fertilization (control, 20 t ha-1 compost, 46 kg N ha−1 + 10 t ha−1 compost, and 92 kg N ha−1) were used as the sub-subplot. Analysis of variance showed that soil management practices were significantly affecting grain yield, N-uptake, and soil properties. In sites, the conventional tillage and rotation system increased the grain yield and N-uptake in contrast to the minimum tillage and monocropping, respectively. Similarly, nitrogen evidently affected the grain yield, N-uptake, and selected soil properties. However, tillage methods differed in their effects on soil chemical properties; soil organic carbon and total nitrogen concentrations were improved through MT compared to CT. Grain yield was significantly associated with NDVI, grain N-content, and N-uptake. Therefore, a CT plus haricot bean-maize rotation system with the addition of solely 92 kg N ha−1 and integrated 46 kg N ha−1 + 10 t compost ha−1 could be recommended for Hawassa Zuria (Cambisols) and Meskan (Chernozem) districts, respectively. However, in order to ensure sustainable maize production in the investigated areas, an integrated N treatment with MT and a rotation system may be recommended, which could improve soil properties.

Plantain-Tree Rubber Intercropping Systems Improved Productivity in the Tropical Humid Zone of Ghana, West Africa

A three-year field trial was conducted between 2014 and 2017 in the Ellembelle and Jomoro districts of the Western region of Ghana where rubber production is common to determine the optimum population density of plantain when grown in combination with immature rubber tree crops. The trials were arranged in a Randomized Complete Block Design with 3 replications. The treatments were sole rubber, sole plantain, and three intercrops of one row of plantain in between two rows of rubber, two rows of plantain in between two rows of rubber, and three rows of plantain in between two rows of rubber. The rubber clone used was GT1 while the variety of plantain used was false horn. The results showed that population density of plantain had significant effect on the growth of the associated rubber. Growing plantain at closer spacing of 1.5 m under the high-density plantain treatment significantly increased plantain yield compared to the other cropping systems. There was a significant positive relationship between population density of plantain and the rubber tree growth and development. The optimum population density of plantain when intercropped with rubber was 1,666/ha. The study showed intercropping was advantageous over sole cropping for both crops.

Impact of Organic Matter, Inorganic, and Biofertilizer Combination on Soybean Yield in Entisol Soil of Indonesia

The study aimed to investigate an effect of organic fertilizer applied to rice in the first planting season for unfertilized soybean as second crop followed by inorganic and biofertilizer applied in the third season on soybean growth and yield under the rice-soybean-soybean cropping pattern in 2016/2017. The main plot was organic: (1) without organic amendment, (2) 10 t·ha−1 of chicken manure, and (3) 10 t·ha−1 precomposted rice straw. The subplot was inorganic N and P fertilizers and commercial biofertilizer (consisting of Rhizobium, nitrogen-fixing bacteria, and P-solubilizing bacteria) applied at planting of soybeans in the second dry season: (1) control (no inorganic and biofertilizer), (2) 50 kg urea ha−1, (3) 100 kg SP36·ha−1, (4) 50 kg urea + 100 kg SP36 ha−1, (5) biofertilizer, (6) biofertilizer + 25 kg urea ha−1, (7) biofertilizer + 75 kg SP36 ha 1, and (8) biofertilizer + 25 kg urea + 75 kg SP36 ha−1. Soybean planted on the first dry season after rice harvested was not fertilized (untreated). The results showed that the chicken manure amendment increased grain yield of soybean in the second season, i.e., from 1.03 t·ha−1 (without organic amendment) to 1.27 t·ha−1, an increase of 23%. There was no effect of rice straw on soybean grain yield. In the third season, however, the residual effect of straw compost or chicken manure increased soybean grain yield by 8% and 20%, respectively. Both straw compost and chicken manure also showed a positive effect on the use of inorganic and biofertilizers in increasing soybean productivity.

Impact of Foliar Application of Zinc and Magnesium Aminochelate on Bean Physiology and Productivity in Ghana

Foliar application of fertilizers can guarantee nutrient availability to beans, leading to higher yield and seed quality. Different approaches including glycine have been used to improve mineral nutrient status of plants toward safer products and improved human health. However, limited research has been undertaken to understand the response of beans to amino Zn and Mg foliar fertilizer application in Ghana. This study was conducted to investigate the effect of zinc, magnesium, and combined zinc and magnesium foliar fertilizer application on two improved common bean (Phaseolus vulgaris L.) varieties locally referred to as Adoye and Nsroma in the forest (Fumesua) and forest-savannah transition (Akumadan) agro-ecological zones of Ghana during the 2018 and 2019 cropping seasons. The treatments were arranged in split-plot design with the two improved common bean varieties as the main plot, and foliar fertilizer options (zinc, 200 g/ha; magnesium, 224 g/ha; combined zinc and magnesium, 100 g/ha Zn and 112 g/ha Mg) and water spray (control) as the subplot treatments. The zinc and combined zinc and magnesium treatments had similar and significantly ( P ≤ 0.05 ) higher plant height of 37.1 cm and 38.7 cm compared to the control and magnesium treatments. The results also showed that chlorophyll content was approximately 15.6% higher in plants treated with zinc plus magnesium compared to the other treatments. Similarly, stomatal conductance was significantly ( P ≤ 0.05 ) increased by 35.6% with zinc plus magnesium treatment relative to the other treatments. The improved chlorophyll content and stomatal conductance in those treatments resulted in ∼55.3–80.6% increase in crop biomass and seed yield. Crop performance parameters such as plant height, canopy spread, and chlorophyll content were significantly higher ( P ≤ 0.05 ) at Akumadan, resulting in a greater seed yield of 1486.2 kg/ha compared to 1365.3 kg/ha at Fumesua. Combined application of zinc and magnesium appears to be a potential soil improvement strategy for common bean production in tropical soil environment of Ghana.

Growth and Yield of Different Varieties of True Shallot Seed on Highland in West Sumatra, Indonesia

Cultivation of true shallot seeds has the potential to be developed in Indonesia because apart from being able to reduce the cost of providing seeds, it also has higher productivity than shallot from tubers. This study aims to determine the appearance of true shallot seed varieties that have high yield potential in the highlands of West Sumatra. The study used a randomized complete block design (RCBD) with 4 treatments of true shallot seed varieties, namely, Trisula, Bima, Lokananta, and Sanren, with 6 replications. The results showed that except for the age of harvest and the number of tubers per hill, the treatment of various varieties of true shallot seeds showed a significant effect on all observed variables. Lokananta variety has better growth component, yield component, and yields compared to other varieties (Trisula, Bima, and Sanren). Cultivation of true shallot seeds in the highlands gives lower yields than in the adapted area (lowland), except for the Trisula variety. Lokananta variety is recommended for use in the highlands of West Sumatra.