High-density field-based 3D reconstruction of rice architecture across diverse cultivars for genome-wide association studies.

A major challenge for utilizing cannabis for modern medicine is the spatial variability of cannabinoids in the plant, which entail differences in medical potency. Since secondary metabolism is affected by environmental conditions, a key trigger for the variability in secondary metabolites throughout the plant is variation in local micro-climates. We have, therefore, hypothesized that plant density, which is well-known to alter micro-climate in the canopy, affects spatial standardization, and concentrations of cannabinoids in cannabis plants. Canopy density is affected by shoot architecture and by plant spacing, and we have therefore evaluated the interplay between plant architecture and plant density on the standardization of the cannabinoid profile in the plant. Four plant architecture modulation treatments were employed on a drug-type medicinal cannabis cultivar, under a density of 1 or 2 plants/m2. The plants were cultivated in a naturally lit greenhouse with photoperiodic light supplementation. Analysis of cannabinoid concentrations at five locations throughout the plant was used to evaluate treatment effects on chemical uniformity. The results revealed an effect of plant density on cannabinoid standardization, as well as an interaction between plant density and plant architecture on the standardization of cannabinoids, thus supporting the hypothesis. Increasing planting density from 1 to 2 plants/m2 reduced inflorescence yield/plant, but increased yield quantity per area by 28–44% in most plant architecture treatments. The chemical response to plant density and architecture modulation was cannabinoid-specific. Concentrations of cannabinoids in axillary inflorescences from the bottom of the plants were up to 90% lower than in the apical inflorescence at the top of the plant, considerably reducing plant uniformity. Concentrations of all detected cannabinoids in these inflorescences were lower at the higher density plants; however, cannabinoid yield per cultivation area was not affected by neither architecture nor density treatments. Cannabigerolic acid (CBGA) was the cannabinoid least affected by spatial location in the plant. The morpho-physiological response of the plants to high density involved enhanced leaf drying at the bottom of the plants, increased plant elongation, and reduced cannabinoid concentrations, suggesting an involvement of chronic light deprivation at the bottom of the plants. Therefore, most importantly, under high density growth, architectural modulating treatments that facilitate increased light penetration to the bottom of the plant such as “Defoliation”, or that eliminated inflorescences development at the bottom of the plant such as removal of branches from the lower parts of the plant, increased chemical standardization. This study revealed the importance of plant density and architecture for chemical quality and standardization in drug-type medical cannabis.

Plant architectural traits associated with yield have been suggested as indirect selection criteria for improving seed yield of dry beans (Phaseolus vulgaris L.) but critical data from selection experiments are lacking. Six dry bean experimental lines of growth habits I, II and III, bred for one or more plant architectural traits, were therefore compared at three locations in Colombia with six other cultivars which were conventionally developed experimental lines of similar growth habits. At each location plant densities of 5, 13, 22, and 30 plants/m2 were established. The objectives were to examine: a) whether lines bred for architectural traits outyielded cultivars and experimental lines bred conventionally, b) the effects of environment and plant density on architectural traits and seed yield, and c) the associations between architectural traits and yield. We did not find a genotype of any growth habit bred for specific architectural traits outyielding the commercial check cultivar. Indeterminate, prostrate type llI, and type II cultivars, in that order, were among the highest yielding regardless of environment and plant density. These also offer the best opportunity for the development of broadly adapted, high yielding cultivars of dry beans for monoculture. Locations, seasons within locations, and plant densities each affected yield and architectural traits. Significant interactions were observed between environment, growth habit, and plant density; and these factors affected yield and all architectural traits. Differences were greatest between determinate and indeterminate growth habits (type I vs. types II and III). For plant density the shape of the response curves for yield was parabolic whereas the shape for type I beans was asymptotic. Curvilinear (types I and II) and linear (type III) increases nodes/m2 were observed as plant density increased. Branch and node number/plant decreased linearly with increasing plant density for genotypes of all three growth habits. Linear reductions in node number on the main stem were observed in indeterminate types II and III with increasing plant density, but internode length did not change. In contrast, the number of nodes on the main stem of determinate type I remained unchanged but internode length increased linearly as plant density increased. Nodes/m2 and branches/plant were positively correlated with yield regardless of environment or plant density. In contrast, nodes/branch and internode length on the main stem were positively correlated with yield over the range of plant densities used, but showed variable correlation over environments. Therefore, development of bean plant ideotypes with enhanced expression of certain architectural traits can result in limited adaptation and reduced yield potential in some environments.

Influence of plant architecture on maize physiology and yield in the Heilonggang River valley

Effects of plant density in broccoli on yield and radiation use efficiency

Good canopy structure is essential for optimal maize (Zea maysL.) production. However, creating appropriate maize canopy structure can be difficult, because the characteristics of individual plants are altered by changes in plant age, density and interactions with neighbouring plants. The objective of the current study was to find a reliable method for building good maize canopy structure by analysing changes in canopy structure, light distribution and grain yield (GY). A modern maize cultivar (ZhengDan958) was planted at 12 densities ranging from 1.5 to 18 plants/m2at two field locations in Xinjiang, China. At the silking stage (R1), plant and ear height increased with plant density as well as leaf area index (LAI), whereas leaf area per plant decreased logarithmically. The fraction of light intercepted by the plant (F) increased with increasing plant density, but the light extinction coefficient (K) decreased linearly from 0.61 to 0.39. Taking the optimum value ofF(95%) as an example, and using measured values ofKfor each plant density at R1 and the equation from Beer's law, the corresponding (theoretical) LAI for each plant density was calculated and optimum plant density (9.72 plants/m2) obtained by calculating the difference between theoretical LAIs and actual observations. Further analysis showed that plant density ranging from 10.64 to 11.55 plants/m2yielded a stable GY range. Therefore, taking into account the persistence time for maximum LAI, the plant density required to obtain an ideal GY maize canopy structure should be increased by 10–18% from 9.72 plants/m2.

The erectophile plant architecture in maize is responsible for high plant density tolerance, yet the genetic basis for this relationship remains elusive, especially for how canopy architecture and plant height related traits at different positions respond to plant density. In this study, nine canopy traits and six plant height (PH) traits were evaluated across four environments under low plant density (57,000 plants/ha, LD) and high plant density (114,000 plants/ha, HD), using a set of 301 recombinant inbred lines originating from two foundation parents in China, the inbred lines YE478 and 08-641. In total, 176 quantitative trait loci (QTLs) for plant architecture related traits (94 only in LD, 44 only in HD and 38 under both densities) and 36 QTL clusters were detected via combined analysis. We identified 21 sharing QTL regions associated with plant height, leaf width and leaf angle at different positions. These results suggest that plant architecture-related traits were greatly influenced by density-specific and environment-specific alleles, and epistasis, QTL × environment interaction and QTL pleiotropy also play essential roles for plant architecture via complex interactions. Though PH-related traits, leaf widths and leaf angles at different positions could be partially affected by several common QTLs, there are still different genetic mechanisms of plant architecture response to plant density. Furthermore, elite line YE478 provided most of the favorable plant architecture alleles for high-density tolerance. Five QTL clusters containing six major QTLs, were useful for further studies of plant architecture and will provide helpful information for ideal plant type, high-density tolerance and marker-assisted selection.

Although faba bean (Vicia faba L.) is a rich source of protein and forage yet its yield is low in Pakistan. Planting time and density are the two major factors affecting faba bean yield. The objective of this study was to evaluate the effect of planting dates and densities on the leaf traits, yield and yield components of faba bean at New Developmental Farm, NWFP Agricultural University, Peshawar. Faba bean was planted on 8 dates from 20 September to 27 December at two-week interval at four planting densities of 150,000, 300,000, 450,000 and 600,000 plants ha -1 . Planting dates significantly affected days to 50% flowering, pods plant -1 , leaves plant -1 , leaf area (LA), leaf weight (LW), specific leaf area (SLA) and specific leaf weight (SLW), while planting densities significantly affected days to 50% flowering, LA, SLW, pods plant -1 , and 100 grains weight. Crop planted on September 20 or October 4 took maximum days to 50% flowering (64), produced more pods plant -1 (21.8), heavier grains (66.13 g), more and heavier leaves plant -1 . Planting density of 450,000 plants ha -1 improved yield and yield components, and further increase in planting density decreased leaf traits, pods plant -1 and grain yield. It may be concluded that faba bean can be planted up to October 4 at 450,000 plants ha -1 to obtain maximum yield in the study area.

Foliar morphology and spatial distribution in five-year-old plantations of Betula alnoides

ABSTRACTA broad range of U.S. maize (Zea mays L.) germplasm was evaluated for plant density tolerance (PDT) to identify potential sources of favorable alleles and to obtain a better understanding the underlying genetics involved. Thirty‐two hybrids created using a set of inbreds representing parentage of key heterotic subgroups were evaluated at plant densities ranging from 47,000 (19,000 plants per acre [ppA]) to 133,000 plants ha−1 (54,000 ppA). Forty‐eight phenotypic traits from five categories (photosynthetic capability, plant architecture, growth responses, source–sink relationship, and general stress tolerance) as well as grain yield were evaluated in three environments that differed for levels of soil moisture availability. The relationship between plant density and grain yield was assessed for each hybrid, with a wide range of responses observed. Five hybrids showed substantial tolerance to plant densities ≥116,000 plants ha−1 based on grain yield performance. Phenotypic trait correlations revealed a subset of traits associated with grain yield across plant densities, with all five categories of traits implicated directly; the subset included leaf angle, upper stem diameter, leaf area required to produce a gram of grain, kernel rows per ear, days to canopy closure, barrenness, kernels per plant, kernel length, leaf number, upper leaf area, staygreen, zipper effect, kernels per row, and anthesis–silking interval. Analysis of gene action for grain yield across plant densities emphasized the prominence of additivity, the increasing importance of nonadditivity as plant density and environmental stress levels increased, and genotype by environment interaction. This work paves the way for further characterization of PDT through quantitative trait locus mapping and candidate gene approaches.

The solar corridor concept examines approaches to better use light in row crops. To achieve this goal, an understanding of the diel patterns of light transmittance to the soil surface in the interrow zone in row crops is necessary. The objective of this study was to investigate the temporal and spatial distribution of light transmittance to the soil surface at different row positions. Light data and leaf area of maize (Zea mays L.) were collected over a period of 2 yr to quantify the spatial distribution of light transmittance to the soil surface under different plant and canopy densities. Leaf area index (LAI) was varied by using two different plant densities and a range of N applications. Photosynthetically active radiation (PAR) was measured using quantum line sensors at three to seven row positions depending on row spacing (0.78 and 0.36 m). Light transmittance to the soil surface varied by position within the row and time of day. The variation was greatest for low N and low plant density spacing treatments. On cloudy days with more diffuse light the variation in light transmittance between the within and row positions was less. Light extinction coefficients decreased as solar elevation increased toward midday. The wide variation in light transmittance to the soil surface in the interrow zone points out the need to manage plant and management properties such as leaf area, plant density, and row spacing to take best advantage of light in the solar corridor.

SummaryThe effects of three planting dates and three plant densities, covering most of the planting dates and densities used in the Netherlands, on yield determining factors of Brussels sprouts (Brassica olerácea var. gemmifera), were studied in field experiments during three seasons. Planting dates were between the end of April and early July. Plant density ranged between 2.7 and 4.4 plants per m2. Planting late in the season initially resulted in more leaves being formed, a higher Leaf Area Index and a longer stem. During crop growth this trend was reversed to a lower number of leaves formed, and in two of the three years a lower LAI and stem length when planting was delayed. The effect of plant density on these characteristics was generally either less pronounced than that of planting date or was absent. There was no, or only limited, interaction between the effects of planting date and plant density on these characteristics. The initial rate of dry-matter accumulation after planting was higher after planting late in the season, but the final amount of standing dry matter was reduced by the late planting. Plant density did not influence the final amount of standing dry matter. There was no interaction between the effects of planting date and plant density on dry-matter accumulation. Planting date and plant density hardly influenced the radiation use efficiency. Overall radiation use efficiency was 2.2 g MJ–1. The time of bud initiation expressed as numbers of days after planting was advanced by delayed planting, but was not influenced by plant density. Planting late in the season decreased the number of buds per plant and in one of the three years also reduced the weight per bud. A decrease in the number of buds per plant due to increased plant density was more than compensated for by the increase in number of plants per hectare. The final number of buds as a percentage of the final number of leaves, was either not, or not consistently, influenced by treatment. Bud dry-matter concentration at final harvest decreased when planting was delayed, but was not influenced by plant density. There was no interaction between the effects of planting date and plant density on bud dry-matter concentration. The dry-matter harvest index of 30–45% was not greatly affected by treatments. To aim for high yields, planting should be as early as field conditions allow.

The objective of this study was to investigate the effects of planting density on the dry-matter (DM) production and yield of maize for whole-plant silage in the north-marginal area in Japan (where accumulated temperature from June to September is 1946°C). Experiments were conducted for 5 years from 1978 to 1982, based on the same design. Wase-homare (early hybrid) was grown at four planting densities from 40, 000 to 100, 000 plants/ha in 1978∼1980 and from 58, 000 to 103, 000 plants/ha in 1981 and 1982 (Table 1). DM weights in each organ and leaf area were measured at the 4th-, 7th-, 11th-leaf fully developed stages, silking stage, and, 3 and 6 weeks after silking. DM yields and percentage of barren plants were measured at harvesting date. The results obtained were as follows : I. As planting desity increased, top growth rates (TGR) during the vegetative growth period were increased. Contrarily, TGR during the ear-filling period were decreased rapidly, resulted in the minimum at the highest planting density of about 100, 000 plants/ha during the latter half of the ear-filling period (Fig. 1). It was due to rapid decrease of net assimilation rates (NAR) during the ear-filling period in high planting density causing increase of mutual shading and specific leaf area (SLA) (Table 2). 2. The optimum leaf area index (LAI), under which maximum TGR obtained, during the ear-filling period, was about 3.0 in all the years (Fig. 5). The planting density which gave the optimum LAI of about 3.0 during the ear-filling period was obtained at the planting density of 73, 000 plants/ha (Fig. 1). 3. The maximum ear growth rates (EGR) during the latter half of the ear-filling period were obtained at 60, 000∼80, 000 plants/ha, and EGR decreased at the higher planting density than the above. Furthermore, the declines of EGR at the higher planting density were promoted in the cold years of 1980 and 1981 (Fig.2). 4. The incidence of barren plant was obviously increased with increasing planting density (Table 2). It reached above 20% as NAR during the latter half of the ear-filling period decreased below 2.0g/m2/day (Fig. 4). 5. Although the highest ear DM yields were obtained at the medium planting density as 60, 000∼80, 000 plants/ha, stover DM yields and total DM yields increased with increasing planting density. Percentage of dry-matter in whole-plant did not differ significantly among planting densities in most years. Ear/Total ratio was decreased and maturity was delayed with increasing planting density (Table 3). 6. It was concluded that the optimum planting desity was about 70, 000∼75, 000 plants/ha for high yield and high quality of maize for whole-plant silage in the north-marginal area.

One of the main factors in obtaining consistently high tomato yields is to optimize the plant nutrition area. Determination of the optimal plant density, on the one hand, prevents oppression of plants at increased density. On the other hand, to avoid unnecessary expenses from the irrational use of the cultivated area. Vegetables are one of the main suppliers of biologically active substances necessary for a good human nutrition. They give the body a lot of vitamins, fiber, hemicelluloses, pectin substances, organic acids, various carbohydrates, mineral salts and a number of other biochemical compounds. Tomato is one of the main protected ground crops for Ukraine. Compared to other crops, tomatoes give early and stable yields. The issue of planting density of tomatoes is still not fully resolved, these elements of technology are not adapted to the soil and climatic conditions of the eastern part of the Left-Bank Forest-Steppe of Ukraine. The objective of our research was to determine the optimal crop density of hybrid tomato of indeterminate type in order to obtain the highest yield without reducing the quality of the product. The method of research. The research was carried out during 2018-2019. In film greenhouses, spring-summer crop rotation. The experiments were carried out with an indeterminate tomato hybrid: Tobolsk F1. Producers of seeds of indeterminate hybrids recommend different plant densities for growing conditions in film greenhouses 2.5-3.5 pcs/m2. Therefore, our research was planned to determine the optimal plant density of the indeterminate tomato hybrid Tobolsk F1 for film greenhouses. The total number of plants is 312 pcs. Sowing of seeds was carried out in the third decade of February. The seeds were sown into cassettes, and the seedlings were dived into pots (volume - 500 cm3) on time. Seedlings were grown using bottom irrigation and, at the age of 3-5 true leaves, the seedlings were planted on a test plot in a film greenhouse without heating. Research results. An analysis of phenological observations of plants showed that a change in the density of plants had practically no effect on the timing and rate of passage of the stages of organogenesis in plants, that is, in all variants of the experiment, the phases of development in plants began simultaneously. Indicators of plant parameters indicate that the data obtained both in the phase of mass flowering and mass fruiting of tomatoes differ among themselves. The difference in biometric parameters can be traced depending on the density of plants. Comparing the main biometric indicators, it can be noted that in the flowering phase, the height of plants ranged from 111.0 to 134.9 cm, in the fruiting phase - from 257.0 to 275.8 cm, while the plants differed in height by the density of 4.0 pcs/m2. The vegetative mass of a plant in the flowering phase was from 1884 g with a plant density of 2.5 pcs/m2 to 1144 g with a density of 4.0 pcs/m2. In the phase of flowering fruiting, the weight of the plant ranged from 1704 g to 1574 g, also decreasing with increasing density. In the flowering phase, an increase in the value of the leaf area indicator was observed to 5.8% with an increase in plant density, and in the fruiting phase, a slight decrease in the indicator to -1.8% was observed with an increase in plant density. So, according to biometric indicators, plants develop better with a density of 3.5 pcs/m2: tomato plants have the best indicators of vegetative mass and plant height, the leaf surface area varies within insignificant limits. The size of the fruits and the yield of standard tomato production are in direct proportion to the density of plants, that is, the more of them per unit area, the lower these indicators. In general, the increase in the density of tomato plants significantly affected the yield. Conclusions. Two-year researches have established that with an increase in plant density, in terms of leaf area in tomato plants of the Tobolsk F1 hybrid, on average, there was a slight fluctuation in the indicator at the level of 0.9-1.1%. The indicator of the vegetative mass of the plant ranged from -4.1 to +1.8% as compared to the control, also decreasing with increasing density. The indicator of plant height both in the flowering phase and in the fruiting phase, on the contrary, grew with an increase in plant density and ranged from -4.0 to + 7.1% compared to the control, while the plants differed in height by a density of 4.0 pcs/m2. In general, the studies carried out give grounds to conclude that in a spring film greenhouse, according to biometric indicators, on average, plants develop better with a density of 3.5 pcs/m2: tomato plants have the best ratio of vegetative mass, plant height and leaf area. The maximum yield of tomato hybrid Tobolsk F1 at the level of 15.8 kg/m2 in the eastern part of the Left-Bank Forest-Steppe of Ukraine was obtained with a plant density of 3.5 pcs/m2.

In summer 1998, two sh2, fresh-market, sweet corn cultivars (`Candy Corner'—large plant size, and `Swifty'—small plant size) were grown at 5, 6.5, 8, and 9.5 plants/m2 to investigate the effects of plant density on growth, photosynthesis, biomass, yield, and quality. Biomass and leaf area per plant were not affected by plant density. Therefore, biomass and leaf area per unit area were increased with increasing plant density. Plant height, leaf chlorophyll, leaf photosynthesis, and transpiration (measured with the LI-COR 6400 portable photosynthesis system) were not affected by plant density. Total cob weight (husk off) and number of ears harvested from plants were increased with increasing plant density. However, marketable yield (number of marketable ears) was not affected by plant density and marketable cob weight (husk off) decreased with increasing plant density due to the reduction in ear size with high plant density. There was a significant increase in percentage of unmarketable ears at plant density higher than 6.5 plant/m2 with `Candy Corner'. Kernel sugar content (°Brix) in both cultivars increased with plant density. According to the results of this experiment, the optimum plant density for fresh-market sweet corn was 5 to 6 plants/m 2.

The experiments were carried out at the Agronomy Experimental Field of Patuakhali Science and Technology University, Dumki, Patuakhali in order to evaluate the effect of sowing date and planting density on the yield and yield contributing characters of sunflower varieties. The experiment comprised of two varieties viz. BARI Sunflower2 and Hysun33 and six planting densities viz. 40cm×25cm, 40cm×35cm, 40cm×45cm, 50cm×25cm, 50cm×35cm, 50cm×45cm. The experiment was laid out in a split-plot design with three replications, where the variety was assigned in the main plot and planting density was assigned as sub-plot treatment. Planting density had a significant influence on all the characteristics of morphological growth, yield, and yield contributing character except plant height at 75 DAS and 90 DAS. In case of Hysun33 variety, the highest number of leaves (21.89), leaf area (3214.22 cm2), head diameter (19.27 cm), head weight (539.07 gm), number of seed head-1 (973.33), seed weight head-1 (65.89 gm), thousand seed weight (67.73 gm), total seed yield (3.27 tha-1) and harvest index (34.30 %) was obtained from 50 cm × 45 cm planting density. On the other hand, in case of BARI Sunflower2 variety the highest number of leaves (18.44), leaf area (3342.90 cm2), head diameter (18.73 cm), head weight (457.80 gm), number of seed head-1 (832.17), seed weight head-1 (53.39 gm), thousand seed weight (64.07 gm) was obtained from 50 cm × 45 cm planting density and the highest stover yield (8.04 tha-1) and biological yield (10.73 tha-1) were obtained from 40 cm × 25 cm planting density. The highest total seed yield (2.94 tha-1) was obtained from 50 cm × 25 cm (8 plants m-2) planting density. Vol. 10, No. 3, December 2023: 229-235