Agronomic and morphological characterization of Medicago intertexta L. for sustainable forage production in Mediterranean environments

Decision letter: Data-driven, participatory characterization of farmer varieties discloses teff breeding potential under current and future climates

The spatial distribution of maize plants influences the number of kernels set per plant by modifying the radiation environment during the critical period for kernel number determination. A two-year field experiment was conducted in Sardinia to explore whether, in a Mediterranean environment, a reduction in row distance can have a positive effect on grain yield of full-season maize hybrids and, if it does, whether this effect is also affected by plant density. Treatments were a factorial combination of three plant densities (6, 8 and 10 plants/m2) and two row spacings (35 and 70 cm). Grain yield and grain number benefited from a reduction in row distance from the canonical 70 cm to 35 cm irrespective of plant density and yield level (14.7 t/ha on average in 2021, 9.9 t/ha in 2022 vs 13.7 and 8.8 t/ha with canonical row distance). Row distance did not affect either the coefficient of extinction of radiation or the intercepted photosynthetically active radiation (PAR) during the critical period for grain number determination. The higher grain number per unit area at the smaller row distance translated into a greater grain yield, which cannot solely be attributed to radiation interception and plant growth rate during the period of kernel number determination. Halving the common row distance is a valuable management option for full-season hybrids grown in Mediterranean environments without nitrogen and water limitations as it seems capable of increasing grain yield via an increase in kernel number per unit area, regardless of plant density and yield level.

LAI and biomass of kenaf as affected by sowing time and plant density: A simple model simulates the time course in a Mediterranean environment

The number of cotton plants grown per unit of ground area has gained attention due to the high prices of inputs and lower production. Cotton yield per unit of area in Henan province has been stagnant in the last few years. The objectives of this study were to investigate cotton growth, yield, boll spatial distribution and biomass accumulation using different plant densities at cultivation and to find out the optimal plant density. A 2-year field experiment was conducted in a randomized complete block design under six plant densities (D1, 15,000; D2, 33,000; D3, 51,000; D4, 69,000; D5, 87,000 and D6, 105,000 ha−1). Cotton grown at lower plant density produced taller plants and high number of leaves per plant while greater number of branches, fruiting nodes and high number of bolls per unit of ground area were produced under high plant density. Boll retention rate decreased as plant population increased and at nodes 1–8 the rate decreased slowly and then increased dramatically. The highest seed cotton yield (4546 kg ha−1) and lint yield (1682 kg ha−1) was produced by D5. The seed cotton and lint yield produced by D5 were 51–55%, 40–37%, 22–26%, 11–15%, 12–15%, 28–30%, 21–24%, 15–20%, 7–13% and 13–17% higher than D1, D2, D3, D4 and D6 during both years of experimentation, respectively. The increase in seed yield was due to higher biomass accumulation in reproductive organs under D5 plant density. The highest average (110.4 VA kg ha−1 d−1) and maximum (126 VM kg ha−1 d−1) rate of reproductive organs biomass was also accumulated by D5 as compared to other plant densities. The results suggest that D5 is the optimal plant density for high reproductive biomass accumulation and high yield for the area of Henan province.

Aim. To investigate the physiological and agrobiological responses of grapevines on different systems of training systems in row plantations depending on the planting density and the possibility of adjusting plants for non-irri- gated crop cultivation under cold semiarid climate. Methods. The field two-way experiment of 2 × 4 was applied to study the effect of two planting density variants (3 × 1.5 m; 3 × 1 m) and four vine training systems (when the horizontal cordon is located at the height of 0.4 m, 0.8 m, 1.2 m, 1.6 m) on the parameters of the leaf area, leaf index, water loss through transpiration, activity of the photosynthetic apparatus of leaves and the yield of Zahrei wine grape cultivar (Vitis vinifera L.). The experiment data were processed using the analysis of variance. Results. The increase in the density of vine row plantations per area units from 3 × 1.5 m to 3 × 1 m enlarges the total leaf area, the exposed leaf area, water loss through transpiration, and yield weight, but these indices decrease in the evaluations per plant. The responses of grapevine to the training systems are similar and independent from the ex- perimental variants of planting density. At the height of the cordon of 0.4 and 0.8 m, the vertical shoot positioning enhances the potential of the photosynthetic capacity of the plantations, but this potential is realized only during the years with lower water deficit for plants. Free-growing shootings on the cordons, located at the height of 1.2 m, form the canopy architecture with relatively low water loss through transpiration which has a positive effect on the activity of the photosynthetic apparatus and yield, especially in dry years. The downward shoot positioning on the cordons of 1.6 m decreases the leaf area of the vines and creates the canopy architecture with increased transpiration which enhances the effect of the water deficit and has a negative effect on the productivity of plants. Conclusions. The agronomic methods of planting and training systems for grapevines ensure the management of the character of spatial shoot location, the formation of certain canopy architecture, and setting the parameters of the leaf area; their optimization mitigates the negative effect of water deficit and provides for adapting the plants for non-irrigated crops under semiarid climate. The positive effect of compacting plantations on crop yield was determined without irrigation in semiarid environments. The variant of planting density of 3 × 1 m decreases the yield on the vines on average by 12.1–31.0 %, as compared to the variant of 3 × 1.5 m. Yet, more dense plantations are remarkable for their yield, which is 18.5–61.3 % higher depending on the training system for vines. Under dry conditions, the most efficient system is the training system with the formation of the horizontal cordon at the height of 1.2 m and free-growing shoots. The system optimizes the leaf area density, and forms the canopy architecture with rather low water loss through transpiration which has a positive effect on the activity of the photosynthetic apparatus of leaves during droughts. Under free growth, the yield of the plantations increases by 4.3–12.3 % on average as compared to the vertical shoot positioning and by 21.3 % – under their downward positioning.

Corn (Zea mays L.) is one of the highest yield crops. Brought in Romania about 300 years ago, our country comes up to the largest corn-growing states with 2.3-2.5 million hectares/year, in EU being recognized as the largest maize grower. The biological material used by Romanian farmers has different origin, thus its agronomic performance is often reduced due to the application of improper management measures. Corn grain yield has significantly increased in the hybrid era and the increase in the number of plants per unit area is suggested as one of the main contributors to yield improvement. In modern maize hybrids, field yield increases with plant density until a maximum population is reached, according to the growing environment and after this maximum, field yield declines. Plant density in farmer’s field is considered a very important stress factor, since competition between different plant species or between different maize hybrids is very strong and reaction of the genotype to this competition can influence yield potential. Four commercial hybrids were studied at four different sowing densities. Greatest grain yields were recorded at the highest sowing densities. Three of the studied hybrids reach the highest yield at the 90,000 pl ha-1 and one at 80,000 pl density. Ear weight is directly affected by the plant density for all the studied hybrids, causing a decrease of this character with the progressive increase of plant density, reaching values between 148.17 g on the first hybrid at 90,000 plants ha-1 and 213.16 on fourth hybrid at 60,000 plants density. Ear length touched values between 15.08 cm at the fourth hybrid by 90,000 plants ha-1 to 19.27 cm for third hybrid at 60,000 plants ha-1. As a main yield component, weight of grains per ear is also influenced by increasing of plant density. The lowest grains yield / maize ear was on Hybrid 1 at 90,000 pl ha-1 (129.26 g) and the biggest value was recorded on Hybrid 4 at 60,000 plants density (197.30 g). The values of yield efficiency (~ 90%) suggest the superior genetic value of the studied maize hybrids even in increasing plant competition conditions.

How do sowing time and plant density affect the pigments safflomins and carthamin in florets of safflower?

IntroductionSafflower (Carthamus tinctorius L.) is a multipurpose plant that has recently attracted renewed interest as a natural source of antioxidant compounds and pigments from its petals, which can be used as alternatives to replace industrial compounds.MethodsIn a split-plot experimental design, the effects of three winter sowings (December, January, and February) and two plant densities (D1, 25 plants m−2; and D2, 50 plants m−2) on petal production and composition in nutrients and antioxidants, including colorants, were examined in safflower (cv. Catima) in a semi-arid Mediterranean environment. Petals were harvested twice: at the flowering of the main shoots (early harvest) and 1 week later, and at the flowering of the lateral shoots (late harvest).ResultsPetal production was reduced as sowing was shifted from December to February. The increase in plant density did not affect petals produced per plant but resulted in greater production per unit area. With sowing in January, crude protein was the highest (up to 17.2%), and oil content was the lowest (down to 3.72%). Total phenols significantly decreased (−6%) with the shift of sowing from December to February. Overall, they were accumulated to a greater extent at lower plant density (D1). Carthamidin (yellow pigment) was higher at the first harvest (up to 8.39%) and decreased thereafter, as carthamin (red pigment) was synthesized. Both pigments tended to decrease with the shift of sowing time and were lower in D1.DiscussionThe nutritional value was positively associated with the nutraceutical value. Greater contents in phenols, flavonoids, and carthamidin, with minor changes in the proximate composition of petals, can be achieved with sowings in late fall–early winter. Harvest at late flowering (~90% flowers open on lateral shoots) resulted in greater yields and carthamin content but lower petal quality, suggesting that the choice of the harvest time of petals strictly depends on the specific trait desired.

Lentil (Lens culinaris Medik.) is widely known among grain legumes for its high nutritional quality, playing an important role in enhancing Mediterranean farming systems as a sustainable crop. Field experiments comparing 121 lentil accessions (microsperma and macrosperma types from different countries) were conducted in a semi-arid environment of south Italy over two growing seasons (2016/2017 and 2017/2018). Their agronomic performance was determined, focusing on phenological, morphological, productive, and qualitative variability. Changes in rainfall and temperatures affected the agronomic traits, especially yield components. In both years, the average grain yield (GY) (2.31 and 2.22 t ha−1, respectively) was above the threshold of 2 t ha−1. Consistent yield exceeding the field average in both growing seasons revealed the superiority of accessions from Egypt, Cyprus, Algeria, Nepal, and Tunisia. Moreover, microsperma yielded more (+0.31 and +0.41 t ha−1 in the first and second year, respectively) than macrosperma accessions. Flowering (DASF—days after sowing to flowering) and thousand seed weight (TSW) appeared to be the most important traits related to grain yield. Flowering earliness seems to act as a mechanism for overcoming abiotic stresses. The analysis of yield components revealed a different productive determinism within the two subspecies. As also highlighted by the Principal Component Analysis, microsperma accessions presented on average a significantly higher number of pods per plant (PP) and seeds per pod (SP), despite the considerable variability among countries of origin. The results showed phenological and morphological variability among genotypes, which should be taken into account in view of future selection programs focused on obtaining lentil ideotypes suitable for the Mediterranean environment.

How to enhance the agronomic performance of cactus-sorghum intercropped system: planting configurations, density and orientation

Groundnut yields are relatively very low in Kenya compared to other countries due to the use of poor agronomic practices and low soil fertility, with phosphorous (P) being the most limiting factor. This study aimed at determining the effect of the rate and time of phosphorous application and planting densities on yield and net benefit of groundnut production. The study was conducted in two locations, Chuka University Horticultural Demonstration Farm and Kenya Agricultural and Livestock Organisation, Embu, Kenya between April and August 2018. The study used a 2 x 3 x 3 factorial experiment laid out in a Randomized Complete Block Design with three replications. There were three factors; P application rates (0, 30, and 60 Kg/ha), time of P application (at sowing, and 14 days after sowing), and planting densities (148,149; 213,331 and 333,334 plants per ha). Data on the number of kernels per pod, number of empty pods and yield of groundnuts were collected and net benefit determined by subtracting the cost of production from the gross product sale price per unit area. Data collected were subjected to analysis of variance using Statistical Analysis Software version 9.4. Significant means were separated using the Least Significance Difference at a 5% probability level. The results of the study showed that the rate and time of phosphorous application and planting densities had a significant effect (p < 0.05) on the yield of groundnuts. The highest kernel yield and net benefit obtained was 1,659.90 and 963.60 Kg/ha while the highest net benefit was KSh 8312 and 12403 which was obtained by applying 30 Kg/ha of P applied at sowing with a plant density of 333,334 plants per hectare at Chuka and Embu, respectively. The study showed that the use of appropriate agronomic practices can lead to sustainable groundnut production, thus ensuring food security and improved farmers’ income. The study recommends spacing of 30 x 10 cm and application of 30 Kg/ha of Phosphorous at sowing for sustainable groundnut production in the study area and within similar agroecological zones.

Charcoal rot, a destructive disease of soybean roots, has limited control options, and the development of resistant cultivars is the most effective, economical, and sustainable strategy. However, tropical cultivars are generally susceptible, while exotic resistant accessions are poorly adapted to tropical conditions. This study represents the initial step toward developing tropical soybean cultivars combining resistance and agronomic performance. We evaluated the agronomic performance of progenies derived from crosses between exotic lines partially resistant to Macrophomina phaseolina (PI 594302 and PI 567562A) and three commercial tropical cultivars with high yield potential (relative maturity groups (RMGs) 5.5, 6.2, and 6.9). Populations were advanced to the F6 generation and assessed for yield, plant height, first pod insertion, and agronomic value using a partial diallel design. Grain yield ranged from 18.5 to 33.2 g·plant−1 across generations. The combining ability analysis revealed predominance of additive genetic effects, highlighting PI 594302 and VMAX RR (RMG 6.2) as key parents for plant height, agronomic value, and grain yield and exhibited the greatest potential for superior progeny across generations. These results identify promising lines with high agronomic performance and adaptation, which will undergo resistance confirmation in subsequent studies, supporting the long-term goal of developing tropical soybean cultivars that combine productivity, sustainability, and tolerance to charcoal rot.

The aim of this work is comparing the two year performance (diameter, total height and mortality) of twenty tree and shrub species in a semi arid environment. The research also wants to supply recommendation on the agronomic cropping techniques in areas where rainfall is the main limiting factor and water use is strictly limited. Woody biomass is gaining increasing importance for energy production in Italy. During the last five years, roughly 5000 ha of Short Rotation Forestry (SRF) have been planted, mostly in northern Italy, especially using poplar clones. However, in Southern Italy, due to the poor rainfall and the lack of knowledge existing on the species to use, few groves have been established. The studied groves were set in December 2005 in a Mediterranean area where the total year rainfall is not higher than 600 mm (mostly in autumn and winter). Twenty species (Salix cinerea, Ulmus carpinifolia, Corylus avellana, Spartium junceum, Acer saccharinum, Morus alba, Saphora japonica, Eleagnus angustifolia, Fraxinus angustifolia (var oxicarpa), Sambucus nigra, Robinia pseudoacacia, Populus nigra, Albizia julibrissis, Populus alba, Salix alba, Ailanthus altissima, Alnus cordata, Ficus carica, Eucalyptus camaldulensis, Celtis australis) were planted in “collection” plots and set in singular plots on single rows (3 m X 0.5 m spacing). Six species (R. pseudoacacia, P. nigra, P. alba, S. nigra, E. camaldulensis, and A. altissima) were planted in eighteen random “experimental” split-plots, using single and twin rows (0.5 m spacing between plants). Plots had a rectangular plant spacing (3 m between singular and twin rows, 0.5 m on each row). Plant density was roughly 6670 cuttings ha-1 in “collection” plots with singular rows and 10950 cuttings ha-1 in “experimental” plots using single and twin rows. The expected harvest interval ranges from 2 to 5 years, depending on the first results. In the “collection” plots, the first results showed good performances in terms of diameter and total height of R. pseudoacacia, E. camaldulensis and E. angustifolia. The highest mortality percentage was recorded for S. nigra, P. nigra, P. alba both in “collection” and “experimental” plots. All other species showed mortality percentage lower than 20%.

In ornamental crop production, growth models as a function of environmental factors can be used as a valuable tool for predicting the timing of a phenological event for the average of a population, for the optimization of environmental conditions inside a growing system, and for making cultural decisions for increasing crop production. The feasibility of an expolinear growth equation was evaluated by predicting the crop growth of single-stemmed rose ‘Vital’ in a single stem system using recirculating nutrient solution. The objectives of this study were to determine a suitable environmental variable and growth parameters, i.e. maximum crop growth rate (Cm), maximum relative growth rate (Rm), and the lost time (tb) for expolinear growth equation using biomass data obtained from 4 experiments with different seasons [cut on Oct. and Nov. in 2004 (Expts. 1 and 2), and Apr. and Jun. in 2005 (Expts. 3 and 4)] and then to predict the crop growth based on an empirical model as a function of the environmental variable and plant density (plants/m2) using estimated parameters of the expolinear growth equation. The growth parameters were estimated by fitting the expolinear growth equation as a function of time, thermal units (TUs, °C·d), or daily incident photosynthetically active radiation (PAR, MJ·m−2·d−1) to observed the biomass per unit area (m2) using a nonlinear regression procedure with Gauss-Newton method. The use of TUs as a variable of expolinear growth equation improved the accuracy of the model and gave a better estimate of growth parameters as compared with those of time or incident PAR integral. Although the fitted expolinear growth equation effectively described the measured fresh and dry mass per unit area, we concluded that TUs was an appropriate variable of expolinear growth equation for single-stemmed rose ‘Vital’ considering some advantage, such as a cheap and easy way for growers to measure the microclimate inside a greenhouse for cut-flower rose production. This study also investigated the effects of TUs and plant density (67, 89, and 107plants/m2) on the growth of single-stemmed rose ‘Vital’ in a single stem system by adjusting the expolinear equation. The growth parameters, Cm, Rm, and tb were estimated by fitting the expolinear growth equation to the measured dry mass measurements obtained from 3 experiments (Expts. 1, 2, and 3) at three different plant densities. Parameters Cm and tb showed a curvilinear relationship with plant density over three experiments and were fitted to the quadratic function. The Rm was substituted with the mean value of the estimated values at each plant density, 0.0082, because there were no significant differences in Rm values among plant density treatments. The estimation of dry mass per unit area by the expolinear growth equation as inputs of TUs and plant density agreed well with the validation data, but the model tended to overestimate dry mass per unit area. The measured dry mass showed a linear relationship with fresh mass regardless of plant densities. The shoot fresh mass per m2 was estimated by an empirical relationship between shoot fresh mass and dry mass using the estimated shoot dry mass. The estimated and measured shoot dry mass and fresh mass showed a reasonably good fit with 1.142 (R2 = 0.988) and 1.168 (R2 = 0.976), respectively.

Vegetative plasticity and floral branching compensate low plant density in modern spring rapeseed