International Journal of Agronomy

Onion is one of the major cash crops and helps improve the livelihoods of smallholder farmers. Although genetically and morphologically different, seedlings of all released onion varieties are transplanted at the ages ranging from 40 to 50 days, which contributes to the low level of productivity in Ethiopia. Therefore, a field experiment was conducted at the research site of Fogera National Research and Training Center during the 2019/20 irrigation season with the objective of identifying the optimum seedling age for improved onion productivity in Northwest Ethiopia. The treatments consisted of three varieties (Adama red, Bombay red, and Nasik red) and four seedling ages (30, 40, 50, and 60 days) of onion, which were laid down in 3 × 4 factorial arrangement using randomized complete block design with three replications. Growth and yield parameters of onion were collected based on the standard procedures and analyzed using SAS version 9.6. The results revealed that both variety and seedling age significantly () influenced plant height, leaf number, bulb diameter, fresh bulb weight, and marketable bulb yield, while their interaction effect did not influence these parameters. Days to maturity was significantly () affected by main as well as by the interaction effects of variety and seedling age. Younger seedling took longer time to mature, while older seedlings matured relatively early. The seedlings of Bombay red variety at 60 days age gave the earliest maturity days (105.33 days) compared to the other combinations. The highest plant height (50.18 cm), leaf number (12.00), bulb diameter (53.47 mm), bulb weight (84.39 g), and marketable bulb yield (29.97 t/ha) were recorded from Bombay red variety where the marketable yield recorded from Nasik red was statistically similar with that of Bombay red variety. Seedlings with 60 days old performed best in terms of all the tested growth and yield parameters including the highest marketability (32.03 t/ha). Accordingly, 60 days old seedlings and Bombay red and Nasik red varieties can be used to increase the productivity of onion in the study area and areas with similar agroecology.

Understanding the carbon dioxide emission rates under different agricultural practices is a critical step in determining the role of agriculture in greenhouse gas emissions. One of the challenges in advocating for an intercropping system as a sustainable practice in the face of climate change is the lack of information on how much CO₂ is emitted by the system. A factorial randomized complete block design study was set up at two distinct agroecological locations (Syferkuil and Ofcolaco) in the Limpopo Province of South Africa to investigate carbon dynamics in sorghum-cowpea intercropping and sole cropping system over two seasons. Intercropping system emitted less CO₂ compared to sole cropping system. In 2018/19 at Syferkuil and 2020/21 at Ofcolaco, intercropping systems emitted 11% and 19% less CO₂, respectively, than sole cropping systems. In both agroecological regions, low cowpea density consistently resulted in higher CO₂ emissions than high density. During the 2018/19 cropping season, sorghum emitted more CO₂ of 5.87 t·ha⁻¹ than cowpea with 5.14 t·ha⁻¹ in a sole cropping system at Syferkuil. Cowpea, on the other hand, emitted more CO₂ of 6.5 t·ha⁻¹ and 10.18 t·ha⁻¹ than sorghum during the 2020/21 cropping season at Syferkuil and Ofcolaco, respectively. Furthermore, intercropping improved the carbon emission efficiency (CEE) of the individual crops in the system. The treatments used in the intercropping and sole cropping systems had a significant impact on the strength of the relationship between carbon stocks and CEE. Our results revealed that sorghum-cowpea intercropping system at a relatively higher cowpea density in a no-till system reduces the amount of CO₂ lost to the atmosphere. The system can thus, be promoted as one of the sustainable farming practices to reduce emissions and improve carbon storage in the soil.

Chickpea is one of the new crops being grown in Zimbabwe for its plethora of benefits in crop production and human diet. However, like most grain legumes preliminary research has shown that chickpea seed has a problem of poor germination hindering the realization of the crops full potential yield. Seed priming has a potential to improve germination of chickpea. Therefore, a laboratory experiment was carried out to determine the effects of seed priming on seed germination. The experiment was laid out as a 4 × 5 factorial in completely randomised design (CRD) with 20 treatments replicated three times. The treatments investigated were five seed priming methods viz hydro-priming, halo-priming (KNO₃), prechill, preheat, and no priming (control); and four chickpea varieties that were ICCV00305, ICCV03404, ICCV97105, and ICCV92944. Hydro-priming involves soaking seed for 24 hours and leaving it to dry in the laboratory for 24 hours at room temperature before it is planted. Halo-priming was done by soaking the seed in a solution with 2.4 g of potassium nitrate and 1.2 ml of distilled water. Prechill treatment involves subjecting seed at a temperature of 10°C for 7 days before planted. Preheating was done by subjecting the seed in an oven at 35° C for 30 minutes. The parameters measured were germination percent, speed of germination, radicle and plumule length, and seedling vigor index. The results showed that preheating and halo-priming chickpea seed significantly improved germination percentage, increased radicle and plumule length, and seedling vigor index. Hyro-priming and no priming reduced germination percentage, decreased radicle and plumule length with poor seedling vigor. Results also indicated that variety ICCCV92318 recorded the highest germination percentage, radicle and plumule length, and seedling vigor index, while variety ICCV97114 recorded the least figures on all tested parameters of chickpea. It can be concluded that preheating seed and halo-priming seed improved germination and seedling vigor in chickpea.

Abiotic stress is a major bottleneck for crop productivity. To counter abiotic stresses, plants have developed several strategies, and the accumulation of polyamine (PA) serving as an osmolyte is one of them. The cellular pool of PAs is primarily regulated by polyamine oxidases (PAOs) either by terminal catabolism or by back conversion (BC) of polyamines. The role of PAO in abiotic stress tolerance has also been reported. Polyamine oxidases are primarily localized in the cytosol, cell wall, and apoplastic regions; however, lately, their peroxisomal localization has also been demonstrated. In this study, we reported the detection of polyamine oxidase isoform 3 from Oryza sativa (OsPAO3) in peroxisome as early as 12 h post-transformation under in vitro conditions using fluorescent microscopy. The gene was also found to be significantly upregulated by salinity, dehydration, cold, and heat stress. We have also demonstrated that the expression of OsPAO3 gene was mediated by a second messenger, calcium. The upregulation of OsPAO3 by salinity, dehydration, cold, and heat stresses suggests that it could be a suitable candidate for providing tolerance to plants against abiotic stress combination or stress matrix, which is a common feature in agricultural field conditions. Furthermore, the data provided here would be valuable in understanding the abiotic stress-mediated signal transduction network of PAOs.

Purple-fleshed sweet potato (PFSP) is a major staple food and feed material in tropical countries. The pandemic of COVID-19 that encouraged healthy lifestyles worldwide further increases the importance of PFSP. Despite its importance, the investment in research to improve PFSP in Indonesia was left behind. The objective of the research was to estimate the genetic variation and genetic distance of new PFSP genotypes prior to variety release. The research trials were arranged in a randomized block design, with nine new PFSP genotypes from polycrosses breeding as treatments and three check varieties in four growing environments in West Java, i.e., Cilembu, Jatinangor, Maja, and Karangpawitan during one season. Agronomic traits data were analyzed by the multivariate analysis. The principal component analysis (PCA) showed high genetic variation of PFSP in four environments. The eigenvalue ranges from 1.92 to 5.29 in Cilembu which contributed to 80.958% variability, 0.543–6.177 which contributed variability to 92.135% in Jatinangor, 0.824–5.695 in Karangpawitan which contributed to 92.117%, and 0.822–4.797 in Maja which contributed to 86.133%. Storage root length, storage root diameter, number of roots per plant, total root weight per plant, number of marketable/commercial roots, marketable/commercial root weight, number of roots per plot, and total storage root weight have a discriminant value of more than 0.7 in PC 1. Agglomerative hierarchical clustering (AHC) showed a wide distribution obtaining two clusters in Cilembu with euclidean distance 1.92–5.29, Jatinangor 1.72–6.09, Karangpawitan 1.28–6.38, and Maja 2.05–5.09. High genetic variation in the four environments greatly supports to the development of PFSP new varieties.

Maize production in Ghana is limited by several factors including inadequate use of improved varieties and poor soil fertility management. To contribute to addressing these challenges in maize production, two on-farm experiments were conducted each in the semi deciduous forest and coastal savannah agroecological zones (AEZs) of Ghana during the major and minor cropping seasons of 2017. The study adopted a 3 × 4 factorial arranged in an RCBD with four replications in the major season. The factors were three maize varieties (Omankwa, Obatanpa, and Ahomatea) and four soil amendments (goat manure at 5 t·ha⁻¹; inorganic fertilizer (N-P₂O₅-K₂O at 95-37.5–37.5 kg·ha⁻¹); 50% goat manure (2.5 t·ha⁻¹) + 50% inorganic fertilizer (N-P₂O₅-K₂O at 47.5–18.75–18.75 kg·ha⁻¹); and the control (no soil amendment)).To evaluate the residual implications of these soil amendments in the minor season, each plot used in the major season was further divided into two except for the control plot, resulting in a split plot design with factorial of 3 maize varieties × 7 soil amendments. The results revealed a significant interaction between maize variety and soil amendment in both seasons with the use of sole inorganic fertilizer resulting in significantly higher () grain yields for all varieties in both AEZs in the major cropping season. In the minor season, the combined treatment of 50% goat manure + 50% inorganic fertilizer resulted in higher grain yields for all the varieties in both AEZs with improved maize (Omankwa and Obatanpa) having significantly higher () grain yields (33–40%) than the landrace (Ahomatea). The significantly lower () performance of maize varieties on the residual plots in both AEZs suggests that there were minimal residual effects from the major season. Thus, in continuously cropped fields, the use of inorganic fertilizer + goat manure is required in addition to improved seeds for sustainable maize production.