Indeterminate Cultivars Research Articles

Response of Hydroponic Tomato Yield and Yield-correlated Morphological Characteristics to Constant or Growth Stage-based Nutrient Management Strategies

In the United States, the annual revenue attributable to tomato production is $1 billion. However, tomato production can cause negative environmental impacts, such as water pollution, often in the form of eutrophication-causing nutrient pollution. Hydroponic production can decrease excess nutrient leaching; however, optimization of nutrient management and cultivar choices could further decrease excess nutrient discharges. The objectives of this study were as follows: to evaluate and compare the responses of tomato growth characteristics, yield, and yield components to two nutrient management regimes (varying nutrient solution concentrations by growth stage and the use of a constant nutrient solution concentration from transplant to termination), and to analyze the effects of growth habits among six cultivars (Big Beef, Cherokee Purple, Heatmaster, Legend, Mountain Fresh Plus, and Tropic) on tomato yield and yield-correlated morphological characteristics. The nutrient management strategies were applied to tomato plants, and data regarding yield and related morphological characteristics were obtained. Data were analyzed using SAS PROC GLM. An analysis revealed no significant difference in the total fruit weight/plant between nutrient management regimes (P = 0.05); however, the mean fruit weight (164.26 g) and diameter (71.70 mm) were significantly greater (P < 0.0001) for plants that received the constant concentration nutrient regime. Indeterminate plants had a significantly greater (P < 0.0001) mean fruit weight (192.76 g) and mean fruit diameter (76.42 mm). Among cultivars, Big Beef had a significantly greater (P < 0.05) total fruit weight/plant (9.25 kg). Applying a constant nutrient concentration to indeterminate cultivars, particularly Big Beef and Cherokee Purple, improved the factors analyzed and could decrease negative environmental impacts while increasing profits of the producers.

Registration of indeterminate and photoperiod‐insensitive IIPG‐7 and IIPG‐11 pigeonpea germplasm

AbstractPigeonpea [Cajanus cajan (L.) Mill.] breeding lines (BL) IIPG‐7 (Reg. no. GP‐326, PI 704909) and IIPG‐11 (Reg. no. GP‐327, PI 704910) were developed at the University of Puerto Rico. Both BL were bred to have indeterminate flowering habit and photoperiod insensitivity. The agronomic performance of IIPG‐7, IIPG‐11, and checks was tested during different growing seasons in Isabela and Lajas, Puerto Rico. IIPG‐7 and IIPG‐11 were early maturing and initiated flowering at 73–84 days after planting (DAP), reaching harvest maturity at 121–127 DAP. This was in comparison to indeterminate cultivars ‘Ariel’, ‘Blanco Yauco’, ‘Kaki’, ‘Pinto Berrocales’, and ‘Super Pinto’, which initiated flowering at 91–102 DAP, reaching maturity at 138–148 DAP in short‐day conditions that occurred in October in both locations. These cultivars had seed yield values of over 1000 kg ha−1, whereas IIPG‐7 and IIPG‐11 produced 721–1010 kg ha−1. In contrast, IIPG‐7 and IIPG‐11 were the only indeterminate genotypes that initiated flowering at 42–88 DAP and reached maturity at 88–172 DAP under long‐day conditions (February, March, and May) in both locations. Seed yields of IIPG‐7 and IIPG‐11 varied from 626 to 2449 kg ha−1 in Isabela and were close to 2000 kg ha−1 in Lajas. IIPG‐7 has tan seed with reddish spots; IIPG‐11 has reddish seed with an average weight of 14 and 15 g per 100 seeds, respectively. The IIPG‐7 and IIPG‐11 BL can be used directly by growers or breeders to develop pigeonpea cultivars that can be planted year‐round.

Stomatal effects and ABA metabolism mediate differential regulation of leaf and flower cooling in tomato cultivars exposed to heat and drought stress.

Co-occurring heat and drought stresses challenge crop performance. Stomata open to promote evaporative cooling during heat stress, but close to retain water during drought stress, which resulted in complex stomatal regulation under combined heat and drought. We aimed to investigate stomatal regulation in leaves and flowers of perennial, indeterminate cultivars of tomatoes subjected to individual and combined heat and drought stress followed by a recovery period, measuring morphological, physiological, and biochemical factors involved in stomatal regulation. Under stress, stomata of leaves were predominantly affected by drought, with lower stomatal density and stomatal closing, resulting in significantly decreased photosynthesis and higher leaf temperature. Conversely, stomata in sepals seemed affected mainly by heat during stress. The differential patterns in stomatal regulation in leaves and flowers persisted into the recovery phase as contrasting patterns in stomatal density. We show that flower transpiration is regulated by temperature, but leaf transpiration is regulated by soil water availability during stress. Organ-specific patterns of stomatal development and abscisic acid metabolism mediated this phenomenon. Our results throw light on the dual role of stomata in heat and drought tolerance of vegetative and generative organs, and demonstrate the importance of considering flower surfaces in the phenotyping of stomatal reactions to stress.

Extração e exportação de nutrientes por cultivares determinadas e indeterminadas de feijão-comum

ABSTRACT There is evidence that the dry mass and nutrient accumulation rates of earlier (determinate) cultivars are faster than those of normal or late cycle (indeterminate). This study aimed to quantify the nutrient extraction and export and calculate the harvest index of determinate and indeterminate common bean cultivars. A randomized block design was used, with four replicates and eight cultivars (BRS FC104, TAA Gol, BRS Estilo, BRSMG Uai, IPR Tuiuiú, BRSMG Marte, Pérola and TAA Dama). The accumulation of dry matter and nutrients at the vegetative and reproductive stages, grain yield and grain nutrient export were determined. The early cultivars TAA Gol and BRS FC104 (Type I - determinate) accumulated more dry matter and nutrients during the vegetative stage than the indeterminate types II and III. However, from R7, no differences were observed among the cultivars for extractions or nutrient exports and harvest index. The cultivars exported 33, 11, 17, 2.3, 2.2 and 1.5 kg t-1 of grain for N, P2O5, K2O, S, Mg and Ca, respectively. Micronutrient exports were 14, 3.7, 70, 13 and 34 g Mg-1 of grain for B, Cu, Fe, Mn and Zn, respectively. The TAA Gol and BRS FC104 determinate cultivars reached the R9 stage at 77 days and the indeterminate cultivars at 85 (BRSMG Marte), 90 (IPR Tuiuiú and BRSMG Uai) and 93 days (TAA Dama and Pérola). BRS Estilo, BRS FC104 and TAA Gol had the lowest grain yield (< 2,200 kg ha-1) and TAA Dama the highest grain yield (3,275 kg ha-1).

Identification and mapping of a recessive allele, dt3, specifying semideterminate stem growth habit in soybean

Key messageA locus, dt3, modulating semideterminancy in soybean, was discovered by a combination of genome-wide association studies and linkage mapping with multiple distinct biparental populations.Stem growth habit is a key architectural trait in many plants that contributes to plant productivity and environmental adaptation. In soybean, stem growth habit is classified as indeterminate, semideterminate, or determinate, of which semideterminacy is often considered as a counterpart of the “Green Revolution” trait in cereals that significantly increased grain yields. It has been demonstrated that semideterminacy in soybean is modulated by epistatic interaction between two loci, Dt1 on chromosome 19 and Dt2 on chromosome 18, with the latter as a negative regulator of the former. Here, we report the discovery of a third locus, Dt3, modulating soybean stem growth habit, which was delineated to a ~ 196-kb region on chromosome 10 by a combination of allelic and haplotypic analysis of the Dt1 and Dt2 loci in the USDA soybean Germplasm Collection, genome-wide association studies with three subsets of the collection, and linkage mapping with four biparental populations derived from crosses between one of two elite indeterminate cultivars and each of four semideterminate varieties possessing neither Dt2 nor dt1. These four semideterminate varieties are recessive mutants (i.e., dt3/dt3) in the Dt1/Dt1;dt2/dt2 background. As the semideterminacy modulated by the Dt2 allele has unfavorable pleotropic effects such as sensitivity to drought stress, dt3 may be an ideal alternative for use to develop semideterminate cultivars that are more resilient to such an environmental stress. This study enhances our understanding of the genetic factors underlying semideterminacy and enables more accurate marker-assisted selection for stem growth habit in soybean breeding.

Variable Yield Responses among Grafted and Nongrafted Late blight–resistant Tomato (Solanum lycopersicum L.) Hybrids in North Carolina

Host resistance is an environmentally and economically sustainable disease management strategy that may be especially beneficial to small-scale and organic growers for whom other management tools such as synthetic pesticides are too costly or not permitted. In western North Carolina, the demand for vine-ripened tomatoes (Solanum lycopersicum L.) from local and organic farms has led to the development of cultivars bred for resistance to geographically relevant diseases, including late blight of tomato, which causes rapid defoliation and lesions on fruit. Grafting tomato plants has the potential to increase plant vigor and yield; however, this effect is known to be dependent on multiple factors, including scion and geographic location. In this study, we evaluated the yield response of one determinate (‘Mountain Gem’) and four indeterminate (‘Mountain Heritage’, ‘Mountain Girl’, ‘Mountain Rouge’, and ‘NC10291’) late blight–resistant tomato cultivars, grafted on tomato rootstock ‘Maxifort’ or nongrafted, on a commercial farm and at two research facilities in western North Carolina. Yield of marketable fruit from grafted plants was greater than that from nongrafted plants at one location (P = 0.008); however, yield response of each cultivar, grafted or not grafted, differed by location. Yield was consistently greater from ‘Mountain Gem’ plants than other cultivars, and grafted ‘Mountain Gem’ plants had greater yields later in the season at two locations than nongrafted plants. Because of the late planting date intended to expose cultivars to the late blight pathogen, the full yield potential of the indeterminate cultivars was not realized at all locations. Disease severity caused by Verticillium wilt (Verticillium dahliae Kleb., Verticillium albo-atrum Reinke & Berthold) was lowest for cultivar Mountain Heritage at two of three locations. Results from this study emphasize the importance of conducting evaluations of grafted tomato plants at multiple locations, including on farm, to optimize the benefits associated with their use.

TM3 and STM3 Promote Flowering Together with FUL2 and MBP20, but Act Antagonistically in Inflorescence Branching in Tomato.

The moment at which a plant transitions to reproductive development is paramount to its life cycle and is strictly controlled by many genes. The transcription factor SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 (SOC1) plays a central role in this process in Arabidopsis. However, the role of SOC1 in tomato (Solanum lycopersicum) has been sparsely studied. Here, we investigated the function of four tomato SOC1 homologs in the floral transition and inflorescence development. We thoroughly characterized the SOC1-like clade throughout the Solanaceae and selected four tomato homologs that are dynamically expressed upon the floral transition. We show that of these homologs, TOMATO MADS 3 (TM3) and SISTER OF TM3 (STM3) promote the primary and sympodial transition to flowering, while MADS-BOX PROTEIN 23 (MBP23) and MBP18 hardly contribute to flowering initiation in the indeterminate cultivar Moneyberg. Protein-protein interaction assays and whole-transcriptome analysis during reproductive meristem development revealed that TM3 and STM3 interact and share many targets with FRUITFULL (FUL) homologs, including cytokinin regulators. Furthermore, we observed that mutating TM3/STM3 affects inflorescence development, but counteracts the inflorescence-branching phenotype of ful2 mbp20. Collectively, this indicates that TM3/STM3 promote the floral transition together with FUL2/MBP20, while these transcription factors have opposite functions in inflorescence development.

Impacts of Aminopyralid on Tomato Seedlings

Effective aminopyralid herbicides are commonly used to control broadleaf weeds in cereals or pastures, but their residues in straw or manure may damage cultivated crops and reduce the yield. In our experiments, the response of tomato plants to aminopyralid at doses of 0.6, 1.5, 3, 7.5, and 15 g/ha was evaluated, and extracts from straw treated with the herbicide Mustang Forte were tested. As the concentration of aminopyralid increased, seed germination was delayed by 1 to 3 days, compared to the control, and all the germinating seeds were deformed already at the lowest concentration of 0.6 g/ha. With the increased concentration of aminopyralid, injury to tomato plants also increased, and at the highest applied dose of 15 g/ha, 93.75% of the tomato plants were damaged. The critical level of concentration of aminopyralid in the soil was determined between 3 and 7.5 g/ha. Treatment with aminopyralid influences plant height in the indeterminate cultivar from an aminopyralid concentration of 3 g/ha and in the determinate cultivar from a concentration of 7.5 g/ha, but not as significantly. Thus, this experiment suggests that in the indeterminate cultivar, aminopyralid has a greater effect on height than in the determinate cultivar. This varietal sensitivity should be subjected to further study.

Evaluation of yield decrease in common beans due to anthracnose (Colletotrichum lindemuthianum) below sub-temperate environment of Northwestern of Rwanda

The research was conducted in the year of 2021-2022 in Burera and Musanze District in Northern province as well as Rubavu District in Western Province with the aim of assessing the yield loss in common beans due to anthracnose by using four cultivars with various levels of resistance in field conditions in environment of Northwestern of Rwanda. Randomized complete block design as experiment design was used in this study where each selected cultivar was grown and the yield loss caused by anthracnose was assessed. A level of significance of P<0.05 . In field trials, on the particularly susceptible cultivar Gikundiro 2 particulary showed the maximum harm in terms of incidence and severity in both infection circumstances. The severity of pod infection ranging from 3-9 (0-) resulted in reduction in quantity of seeds which contain a pod ranging from 10.52 % -57.76 % and the loss in weight of seeds per pods ranging from 21.93 % - 68.77 %, both demonstrated a direct impact on seed yield. However, determinate cultivars showed a greater drop in yield (58.5%) than indeterminate cultivars (10.52%) although both were sensitive, based on this research, anthracnose causes economic yield loss on variety Gikundiro 2 and Vuzimpundu.

The auxin-responsive transcription factor SlDOF9 regulates inflorescence and flower development in tomato.

Understanding the mechanisms underlying differentiation of inflorescence and flower meristems is essential towards enlarging our knowledge of reproductive organ formation and to open new prospects for improving yield traits. Here, we show that SlDOF9 is a new modulator of floral differentiation in tomato. CRISPR/Cas9 knockout strategy uncovered the role of SlDOF9 in controlling inflorescence meristem and floral meristem differentiation via the regulation of cell division genes and inflorescence architecture regulator LIN. Tomato dof9-KO lines have more flowers in both determinate and indeterminate cultivars and produce more fruit upon vibration-assisted fertilization. SlDOF9 regulates inflorescence development through an auxin-dependent ARF5-DOF9 module that seems to operate, at least in part, differently in Arabidopsis and tomato. Our findings add a new actor to the complex mechanisms underlying reproductive organ differentiation in flowering plants and provide leads towards addressing the diversity of factors controlling the transition to reproductive organs.

Growth habit and in-row distance for bell pepper under protected culture

ABSTRACT Bell pepper (Capsicum annuum L.) production under high tunnels requires appropriate plant density and growth habit to ensure efficient use of space. This study assessed the effects of in-row spacing and bell pepper growth habit on growth and yield under high tunnels. Determinate, cv. Crusader, and indeterminate, cv. Maria, seedlings were transplanted in single rows spaced at 20, 25, and 30 cm between plants (equivalent to 31,245; 24,996; and 20,830 plants∙ha−1, respectively) with growth habit as the main plot and in-row distance as sub-plot. Leaf greenness, plant nutrient status, plant height and marketable fruit weight and number were measured. Yield per plant and per unit area were affected by growth habit and in-row distance. The indeterminate cultivar produced 33% more fruit and 13% more yield per plant than the determinate cultivar, while the determinate cultivar produced 24% heavier fruit than the indeterminate cultivar. In-row distances of 20 and 25 cm resulted in similar fruit number per hectare, while 30 cm plant spacing reduced fruit per hectare by 20%. Overall yield was not affected by in-row distance. An economic analysis is necessary to evaluate the potential profitability of a bell pepper system based on indeterminate cultivars and an in-row distance of 30 cm.

Dry matter accumulation and nutrient uptake in determinate and indeterminate soybeans

The objective of this study was to determinate dry matter production and macronutrients accumulation in the shoots of soybean plants of determinate and indeterminate types of growth. The experiment was carried out in Dourados, Mato Grosso do Sul, Brazil, in the 2016/17 season. The experimental design was a random block, with two soybean cultivars (BRS 317 determinate and BRS 1001 indeterminate), seven collection times (15, 30, 45, 60, 75, 90 and 105 days after emergence) and four replicates. At each collection, the plants were divided into leaves, stems, branches, pods and grains, and then submitted to laboratory analysis to determine the nutrients contents in each organ. Macronutrient accumulation in both cultivars followed the order: N > K > Ca > P>Mg > S. The indeterminate cultivar produced more dry matter, and had a longer time required for maximum production, than the determinate cultivar. The indeterminate cultivar exported more nutrients than did the determinate cultivar. Thus, the former demanded more attention to replacement of nutrients to the soil.

Yield Performance and Response to High Plant Densities of Dry Bean (Phaseolus vulgaris L.) Cultivars under Semi-Arid Conditions

To identify eco-efficient bean cultivars that can be planted at high densities for sustainable bean production under climate change, this study analyzed the performance of ten dry bean (Phaseolus vulgaris L.) cultivars grown at 90,000, 145,000 and 260,000 plants ha−1 under rainfed semi-arid conditions in Mexico. The study compared the yield and yield components (leaf area index (LAI), pods per plant, and hundred seed weight) of the cultivars. We also analyzed the dry matter distribution (DMD), growth rate (GR), radiation use efficiency (RUE), and harvest index (HI) of the best performing cultivars to determine how they respond to higher densities. The cultivars were established under similar planting and management conditions during two growing seasons. The precipitation for the first and second seasons were 175 and 492 mm, respectively, representing 57% and 160% of the mean precipitation in the area during the July–October growing period. Pinto Saltillo, a drought-tolerant indeterminate semi-prostrate cultivar, and Azufrado 2, a determinate shrub cultivar, performed best at high densities under low-precipitation conditions (175 mm). Both cultivars responded to the highest density (260,000 plants ha−1) with increases of 54% to 69% (0.7 to 1.1) in LAI and 21% to 86% (0.32–0.81 Mg ha−1) in yield. The two cultivars responded to increasing plant density with a modification in their fraction of DMD over plant parts and a change in their GR from 0.23–0.25 at low density to 0.96–1.74 gr m−2 day−1 at high density. The two cultivars had an RUE of 3.8 to 4.4 g MJ−1 and HI of 0.31 to 0.36 at high planting density. Farmers’ use of these commercially available cultivars proven to have high yields and the ability to respond favorably to high densities under rainfed conditions can be a viable short-term strategy to increase dry bean production for sustainable agriculture in semi-arid temperate regions.

Yield and Nutritional Response of Greenhouse Grown Tomato Cultivars to Sustainable Fertilization and Irrigation Management.

Tomato is considered one of the most important crops worldwide from nutritional and economic standpoints, and, in this respect, sustainable production should be a prime objective, particularly in terms of fertilization and irrigation management. The aim of this study was to compare the effects of two fertilization types (chemical or organic) and two irrigation regimes (67% or 100% of evapotranspiration replenishment) on biometrical, biochemical, and yield parameters of three indeterminate cultivars of tomato grown in a greenhouse. The results showed that the effect of organic fertilization was better compared to chemical fertilization for lycopene accumulation and antioxidant activity, as well as for the lower concentrations of any of the macroelements in the tomato fruits; therefore, organic fertilization can be used as an alternative to chemical fertilization in sustainable horticulture. In each cultivar under the same fertilization type, the effect of irrigation was significant on yield and the number of fruits, but the 100% evapotranspiration restoration did not enhance the fruit concentration of all the macroelements and microelements compared to 67% irrigation regime. Higher concentrations of macro- and microelements in the chemically fertilized fruits compared to the organic ones, regardless of the cultivar and the irrigation regime, suggest that the inorganic substances are more easily absorbed by plants under a protected environment. Organic fertilization positively affected the lycopene and antioxidant activities of tomato fruits, thus proving to be a valuable alternative to chemical fertilization in sustainable agriculture, although the product premium quality also depends on the cultivar used.

Yield and fruit quality of high-tunnel tomato cultivars produced during the off-season in South Texas

The Rio Grande Valley (RGV) of South Texas is one of the most diverse vegetable-producing regions in Texas. Traditionally, tomatoes in the RGV have been grown in open field during the spring and fall, but the production area has declined significantly due to the high pressure of pests and diseases. RGV open-field cultivation during winter is limited to cold-tolerant vegetables such spinach and cabbage due to the risk of cold days and nights. As an alternative, high tunnels offer an environment protected against pests and diseases, wind, and low temperatures. Here, we studied the feasibility of RGV high-tunnel tomato production to identify the planting date, tomato type, and cultivars best suited for producing high-quality tomatoes during winter. The high tunnel maintained temperatures above 21 °C during chilly days without providing additional heat. In addition, whitefly and thrips populations remained low during most of the cropping season, although pesticide control was required at crop establishment to lower their populations. Overall, higher yields were achieved in October compared to November planting and from determinate compared to indeterminate cultivars. Determinate tomato cultivars TAM Hot-Ty, Mykonos, and TAM HT1 transplanted in October produced up to 96.4, 129.13, and 85.98 t/ha, respectively. Among the cultivars tested, TAM Hot-Ty and TAM HT1 possessed the highest concentrations of soluble solids, with ° Brix >5 %. In an organoleptic test, fruits from high tunnel tomatoes were ranked higher than Texas supermarket tomatoes imported from other regions in terms of flavor, color, and overall characteristics. This study demonstrates that tomato high-tunnel production offers a viable alternative to open-field production in South Texas and could provide a source of high-quality locally produced tomatoes to Texas and nearby markets.

Effects of maturity group and stem growth habit on the branching plasticity of soybean cultivars grown at various planting densities

ABSTRACT To elucidate the effects of maturity and the stem growth habit on the planting density-dependent branching plasticity of soybean cultivars, we studied the branch traits of 12 cultivars or lines planted at different densities (8.3, 16.7, and 22.2 plants m−2) in Sapporo (2012) and Ebetsu (2013). The 12 cultivars and lines consisted of three determinate cultivars from Hokkaido, three indeterminate cultivars from the northern US, and near-isogenic lines with the backgrounds of Canadian, US, and Japanese cultivars exhibiting diverse stem growth habits. We investigated the relationship between the maturity or stem growth habit and branching plasticity, which was calculated based on the ratios of different branch traits under sparse and dense planting conditions. The use of the ratios of the total branch length and the number of nodes per branch under sparse and dense planting conditions as a measure of branching plasticity revealed varietal differences across years. For the determinate and indeterminate cultivars in both years, branching plasticity was positively correlated with the number of days until stage R5 (onset of seed filling), which is when branches cease to elongate. Comparisons of Japanese and US cultivars and near-isogenic lines for the Dt1 gene (mediating the stem growth habit) indicated that the branching plasticity of indeterminate cultivars and lines is greater than that of determinate cultivars, with a large variation among backgrounds and cultivars. The results of this study imply that branching plasticity is greater in late-maturing soybean cultivars. Moreover, the indeterminate growth habit substantially enhances branching plasticity.

Minimum optimal seeding rate for indeterminate soybean cultivars grown in the tropics

AbstractThe minimum optimal seeding rate in soybean [Glycine max (L.) Merr.] is the least seeds required to achieve optimal yield. This is a function of the crop phenotypic plasticity in response to plant density. However, the effect of seeding rate reduction on the seed composition and yield of cultivars with contrasting branching potentials needs to be better elucidated. The objectives were to evaluate the impacts of reducing the seeding rate on production and to quantify the minimum optimal seeding rate for seed, oil, and protein yield in soybean cultivars with contrasting plant architectures. The field experiment was conducted for two growing seasons in a 5 × 2 factorial scheme in a randomized complete block design with five replications. The treatments consisted of five seeding rates (100, 80, 60, 40, and 20% of the recommended seeding rate) and two indeterminate cultivars (BRS 1010IPRO and NS 5959IPRO). Both cultivars showed a minimum optimal seeding rate below the recommended rate. Pods per m2 and the number of seeds per pod were the yield components responsible for the compensatory effect in response to lowering the seeding rate. Thousand seed weight was the main yield component responsible for yield loss below the minimum optimal seeding rate. Both cultivars showed high branch yield in response to seeding rate reduction. BRS 1010IPRO has a higher potential for seeding rate reduction than NS 5959IPRO. The minimum optimal seeding rate for seed yield in NS 5959IPRO led to lower protein yield and higher oil yield.

Biochars improve tomato and sweet pepper performance and shift bacterial composition in a peat-based growing medium

We previously observed that the biochars used in this study can replace 15% (v/v) of perlite in a peat-based growing medium (PBGM) without causing any harm to microbial biomass. However, little is known about their impacts on the plant-microbe-soil interactions and crop productivity. Thus, the aim of the present work was to evaluate in greenhouse trials, the effect of substituting perlite in PBGM by three types of biochar on tomato cv. Micro-Tom and sweet pepper cv. Redskin, growth and yield, on their water and fertilizer use efficiency and on the bacterial diversity found in PBGM. Biochars were derived from maple bark pyrolysed at 550 °C (M550) and 700 °C (M700) and from pine chips pyrolysed at 700 °C (P700). Tomato and sweet pepper plants were grown in a greenhouse and fertigated with mineral fertilizer at full or half of the recommended level. Compared to the control without biochar, adding 5, 10 or 15% (v/v) biochar improved plant water use efficiency and increased tomato and sweet pepper fruit dry weight yield respectively, by up to 32% and 54%. Biochar significantly increased N and P uptake efficiency, while reducing loss of NO3− and PO43− in leachates. In PBGM used to grow sweet pepper under full fertigation, the presence of 15% (v/v) M700 or P700 biochars significantly increased bacterial richness probably through the improvement of some ecological micro-niches such as C accessibility. This also allowed the establishment of potential plant growth promoting bacteria particularly Agrobacterium, Cellvibrio and Streptomyces, which showed a positive correlation with plant productivity and the chemical properties of PBGM. Our results suggest that the higher PBGM pH reached by adding 15% (v/v) biochar improved plant growth by increasing carbon, nitrogen and phosphorus availability and by favoring the establishment of plant beneficial bacteria. Therefore, substituting 15% (v/v) of perlite in PBGM with the three tested biochars appears to be a beneficial practice towards sustainable greenhouse production of tomato and sweet pepper, and this practice merit further investigation with other crops such as indeterminate cultivars.

The long-term effect of legumes as forecrops on the productivity of rotation winter triticale–winter rape with nitrogen fertilisation

ABSTRACTThe aim of the study was to determine the long-term effect of legumes as forecrops on the productivity of rotation with nitrogen fertilisation. The rotation included: legumes + spring barley, winter triticale and winter rape. The study was conducted as a two-factorial field experiment with four replications. The present study showed that legumes, as forecrops, increased the yield of WT cultivated in the second year of rotation. The seed yield of WR cultivated in the third year of rotation significantly increased after all legume forecrops, with the exception of PEA. Yielding of these crops depended also on nitrogen fertilisation. In the case of WT doses 120 kg N ha−1 and 180 kg N ha−1 there was an increased yield compared with control independent of forecrop, but there were no significant differences between doses 120 and 180 kg N ha−1. The conclusion is that we do not need to use dose 180 kg N ha−1 for WT cultivated directly after legumes. In the cultivation of WR in the third year of rotation there is no need to use a dose of nitrogen 180 kg N ha−1 if the fore-fore-crops were indeterminate cultivars of BL or YL.

Quantitative impacts of different planting arrangements on the populations of natural enemies in soybean

Natural biological control is an important alternative for the control of insect pests using natural enemies that occur naturally in agroecosystems. The potential of these insects can increase when they are adequately managed. Thus, the objective of this study was to quantify the populations of natural enemies in soybean cultivars with different growth habits planted in different arrangements. The experiment consisted of eight treatments: four planting arrangements and two soybean cultivars, with four replicates. The populations of natural enemies were evaluated from the vegetative stage V3 to crop harvest using a shaking-cloth. A population survey of the beneficial arthropods present on the soil surface was performed in the reproductive stages R2 and R3 with the installation of modified pitfall traps. The main natural enemies that occurred in the culture were Class Arachnida, Order Heteroptera, Order Hymenoptera, Order Coleoptera and Order Dermaptera. The populations of the natural enemies assessed using the shaking-cloth did not show significant differences. However, in the evaluations with the modified pitfall traps in the reproductive stage R3 in the crossed arrangement, the populations of the Coleoptera and Dermaptera orders were higher in the determinate cultivar than in the indeterminate cultivar.