Growth Of Pepper Seedlings Research Articles

Seed Germination and Initial Growth of Pepper Seedlings is Influenced by Environment Temperature and Priming Method

The effects of different environment temperatures, priming treatments and priming durations on germination parameters and early growth of pepper seedlings were investigated. Seeds were hydro primed in distilled water, or osmo primed in two different water potentials (-0.15 and -0.5 MPa) of polyethylene glycol (PEG) 8000. Both, hydro primed and osmo primed seeds were subject of two different imbibitions periods, 48 and 72 hrs. In addition to primed seeds, an equal sample of non primed seeds was included in the experiment as a control variant. Following priming, the seeds were subjected to germination tests at two different environment temperatures, respectively 18 0C and 24 0C. In general, there was no significant effect of hydro priming on germination parameters or early growth of pepper seedlings. On the contrary, significantly higher germination percentage and germination speed and significantly shorter mean germination time than the non primed seeds were obtained due to seed osmo priming by PEG. Similarly, an enhanced seedling growth, especially under suboptimum temperature conditions was evidenced in PEG primed seedlings. Apart from germination speed, the increase of PEG concentration from -0.15 to -0.5 MPa had no effect to germination parameters of pepper seeds. The extent of the imbibitions period over 48 hrs did also have no benefits on germination parameters.

RESPON PERTUMBUHAN BIBIT LADA (Piper nigrum L.) PADA APLIKASI PEMBERIAN BERBAGAI KOMPOSISI N:P:K DAN KONSENTRASI POC

This research was carried out at the Darul Mukhlisin Islamic Boarding School in Padang Lampe, Muslim University of Indonesia, Pangkep Regency, South Sulawesi, which took place from March to September 2019. The study was aimed at analyzing the effect of the composition of N: P: K on the growth of pepper seedlings, analyzing the effect of the concentration of Organic Fertilizers Liquid (POC) on the growth of pepper seedlings, analyzing the interaction between giving the composition of N: P: K and giving POC on the growth of pepper seedlings. This research was compiled using a Randomized Group Design (RBD) consisting of two factors. The first factor is the composition of N: P: K consisting of: N: PK 1 : 0 : 0 / plant, N: P: K 1 : 1 : 1 / plant, N: P: K 2 : 1 : 1 / plant and N : P: K 2 :1 : 2 / plant. The second factor is the concentration of Liquid Organic Fertilizer consisting of no POC, POC 0.05% / liter of water, POC 0.10% / liter of water and POC 0.15% / liter of water. The results showed that the best effect on the use of the composition N: P: K on the length of the shoot, number of leaves and leaf area of pepper seedlings. The use of liquid organic fertilizer concentration of 0.10% / liter of water gives the best effect on shoot length, number of shoots, and number of leaves and leaf area, and there are significant interactions between the composition factors of N: P: K and POC concentration on the shoot length variable of pepper seedling growth.

Regulation of nitric oxide to Capsicum under lower light intensities

Capsicum is one of the main vegetables of facility cultivation in winter and spring in many places of the world. The lower light intensities formed in the facility seriously affects the normal growth and development of pepper plants. Therefore, it has important application value to carry out the regulation of pepper plant growth under lower light intensities. To reduce the adverse effects of lower light intensities on the growth of pepper seedlings (Capsicum annuum L.), Capsicum species (WM-1) were used as test materials. Growth related indicators of C. annuum plants under different light intensities were tested after spraying sodium nitroprusside (SNP, a NO donor). The results showed that nitric oxide (NO) increased significantly the plant height, stem diameter, number of branches and leaf area of plants under lower light intensities; at the same time, it also increased the activities of antioxidant enzymes (superoxide dismutase, peroxidase, and catalase) in pepper seedlings; NO-scavenger c-PTIO, under low light stress, the NR inhibitor tungstate and NOS inhibitor L-NAME inhibited the activity of the antioxidant system; however, their harmful effects on growth, antioxidant system could be reversed by the addition of SNP; in addition to this, NO also increased chlorophyll a, chlorophyll b, and chlorophyll (a+b) synthesis, decrease the chlorophyll a/b ratio, and generally enhance the expression level of chlorophyll synthesis genes (HEMA1, CAO and GGPS2). This indicated that NO can alleviate the adverse effects of lower light intensities for pepper growth and improve the photosynthetic performance of pepper leaves in lower light intensities conditions.

CaDHN4, a Salt and Cold Stress-Responsive Dehydrin Gene from Pepper Decreases Abscisic Acid Sensitivity in Arabidopsis.

Dehydrins play an important role in improving plant resistance to abiotic stresses. In this study, we isolated a dehydrin gene from pepper (Capsicum annuum L.) leaves, designated as CaDHN4. Sub-cellular localization of CaDHN4 was to be found in the nucleus and membrane. To authenticate the function of CaDHN4 in cold- and salt-stress responses and abscisic acid (ABA) sensitivity, we reduced the CaDHN4 expression using virus-induced gene silencing (VIGS), and overexpressed the CaDHN4 in Arabidopsis. We found that silencing of CaDHN4 reduced the growth of pepper seedlings and CaDHN4-silenced plants exhibited more serious wilting, higher electrolyte leakage, and more accumulation of ROS in the leaves compared to pTRV2:00 plants after cold stress, and lower chlorophyll contents and higher electrolyte leakage compared to pTRV2:00 plants under salt stress. However, CaDHN4-overexpressing Arabidopsis plants had higher seed germination rates and post-germination primary root growth, compared to WT plants under salt stress. In response to cold and salt stresses, the CaDHN4-overexpressed Arabidopsis exhibited lower MDA content, and lower relative electrolyte leakage compared to the WT plants. Under ABA treatments, the fresh weight and germination rates of transgenic plants were higher than WT plants. The transgenic Arabidopsis expressing a CaDHN4 promoter displayed a more intense GUS staining than the normal growth conditions under treatment with hormones including ABA, methyl jasmonate (MeJA), and salicylic acid (SA). Our results suggest that CaDHN4 can protect against cold and salt stresses and decrease ABA sensitivity in Arabidopsis.

The fungicide "fluopyram" promotes pepper growth by increasing the abundance of P-solubilizing and N-fixing bacteria.

Fluopyram, as a reasonably good fungicide and nematicide, is widely used to control agricultural pests worldwide. However, its effects on soil microbial communities and plant growth remain controversial. Therefore, in this study, we investigated the effects of three concentrations (0.5, 1.5, and 5.0 mg/kg) of the fluopyram (Lufuda 41.7% a.i., suspension concentrate, SC) on the pepper rhizosphere microorganisms and pepper seedlings growth in a plant growth room. Moreover, we also investigated the dissipation of fluopyram in the soil, pepper roots, and leaves across a time interval of 45 days. The results showed that fluopyram application increased the number of pepper rhizosphere phosphate (P)-solubilizing bacteria, the abundance of nitrogen (N)-fixing nifH genes, and the pepper seedling growth. The results of terminal restriction fragment length polymorphism (T-RFLP) analysis demonstrated that fluopyram did not alter rhizosphere bacterial community structure and diversity. However, fluopyram did increase the relative abundances of 138 bp and 400 bp T-RFs closely representing Bacillus and Rhizobium genera that were known as efficient plant growth promoting bacteria with P-solubilization and N-fixation properties. Corresponding to the increase of plant growth and beneficial microbes, the half-lives of fluopyram in soil and plant tissues also decreased that nevertheless suggested the role of plant-microbe interactions in the faster removal of fluopyram after application. Our results suggest that short-lived and easily degradable pesticides may have less toxicological effects on soil health while their judicious use may reshape plant-microbe interactions in favor of the plant growth.

Effects of LED light quality on the growth of pepper seedling in plant factory

The extensive environment, especially low temperature and weak lighting in winter and spring, which limits the growth of pepper (Capicum annuum L.) seedlings, the use of plant factory with artificial lighting technology can effectively control the lighting environment to produce high-quality seedlings. In this study, white LED lamps with R:B ratio of 0.7 (L0.7) and 1.5 (L1.5) and red-blue LED lamps with R:B ratio of 3.5 (L3.5) were used to cultivate seedlings of “CAU-24” pepper in the light intensity of 250 μmol/m2·s and photoperiod of 12 h/d, white fluorescent lamps with R:B ratio of 1.7 (F1.7) was used as control. The results showed that plant height, stem diameter, hypocotyl length, biomass accumulation, light energy use efficiency (LUE) and electric energy use efficiency (EUE) of pepper seedling under L1.5 were the highest. After 36 days of sowing, the dry weight of shoot reached 302.8±45.2 mg/plant. Leaf area reached maximum value of 153.5±22.0 cm2 under L0.7. The contents of chlorophyll a, chlorophyll b and total chlorophyll of pepper seedling leaves under all kinds of LED light were greater than F1.7, but there was no significant difference in net photosynthetic rate. The total dry weight with lamp electric power consumption of L1.5 were 3.0 g/(kW·h) which was 1.5, 2, and 3 times greater than that of L3.5, L0.7, and F1.7, respectively. Therefore, compared with fluorescent lamp and other LED lamps, the white LED light quality with R:B ratio of 1.5 is suitable for pepper seedling production in plant factory because of the high LED lighting efficiency, greater LUE and EUE. Keywords: pepper seedlings, LED light quality, R: B ratio, light energy use efficiency (LUE), electric energy use efficiency (EUE) DOI: 10.25165/j.ijabe.20191205.4847 Citation: Liu N, Ji F, Xu L J, He D X. Effects of LED light quality on the growth of pepper seedling in plant factory. Int J Agric & Biol Eng, 2019; 12(5): 44–50.

Isolation and Identification of Bacillus amyloliquefaciens IBFCBF‐1 with Potential for Biological Control of Phytophthora Blight and Growth Promotion of Pepper

AbstractIn this study, 76 bacterial strains were isolated from the rhizosphere soil of pepper. Of these, 23 bacterial isolates capable of inhibiting Phytophthora capsici growth were selected. Among the antagonistic bacteria, one strain, IBFCBF‐1 showed the strongest antagonistic activity, and was identified as Bacillus amyloliquefaciens based on the results of 16S rRNA gene sequence analysis, physiological and biochemical testing, and morphological characteristics. When tested with a dual‐culture method and with laboratory greenhouse studies, the strain IBFCBF‐1 was found to be a potential biocontrol agent for controlling the plant pathogen, P. capsici. Moreover, it showed high efficiency and broad‐spectrum antifungal properties in vitro. Under greenhouse conditions, IBFCBF‐1 could significantly promote the growth of pepper seedlings, and was able to solubilize phosphate, and produce indole acetic acid (IAA) and ammonia. This study clearly demonstrated that IBFCBF‐1 is a potential candidate exhibiting phytophthora blight‐suppressive and plant growth‐promoting effects on pepper.

Isolation and characterization of antagonistic endophytes from Dendrobium candidum Wall ex Lindl., and the biofertilizing potential of a novel Pseudomonas saponiphila strain

Many endophytic bacterial strains are now successfully used for plant-growth promotion (PGP) and as biocontrol agents (BCA) against plant diseases. This is a promising strategy for the improvement of crop productivity, thereby reducing the use of chemical pesticides and fertilizers. The objectives of this study were to isolate endophytic bacteria from the medicinal plant Dendrobium candidum Wall ex Lindl in China, and evaluate the biological control and PGP characteristics of these bacteria. Antagonistic tests were performed against fungal pathogens. Twenty-two of the 83 bacterial isolates showed antagonistic activities. These antagonistic isolates were screened in vitro for PGP traits, such as the production of indoleacetic acid (IAA), siderophores, proteases, and phosphate solubilization. Based on the tested PGP traits, strain YW was selected for further study. Strain YW was identified as Pseudomonas saponiphila based on its 16S rRNA and gyrB gene sequences. We detected the antifungal metabolite-encoding genes phlD, and hcnBC genes encoding 2,4-diacetylphloroglucinol (2,4-DAPG) and hydrogen cyanide (HCN) from strain YW. We measured the effect of strain YW on the growth of pepper seedlings under greenhouse conditions. Our results showed that its antifungal potential may be attributed to 2,4-DAPG and HCN antibiotics, as well as protease and siderophore production, and growth promotion may be related to the ability of isolate YW to synthesize IAA and solubilize phosphate. The PGP and antifungal activities of strain YW suggest that it may be exploited as a potential bioinoculant agent. This is the first report of a P. saponiphila strain with PGP attributes.

Brassinosteroid alleviates chilling-induced oxidative stress in pepper by enhancing antioxidation systems and maintenance of photosystem II

To explore regulated mechanisms of Brassinosteroids-induced chilling tolerance, we studied the involvement of foliar sprayed 24-epibrassinolide (EBR) in the growth, lipid peroxidation, distribution of absorbed energy and excitation energy, chlorophyll fluorescence characteristics and antioxidant defense system of pepper seedlings under chilling stress. We found that low temperature retarded the growth of pepper seedlings, but foliar spray of EBR solution markedly improved the photoinhibition by increasing maximum quantum efficiency of photosystem II (Fv/Fm), the actual photochemical efficiency of photosystem II, photochemical quenching coefficient and the efficiency of excitation capture of open PSII center (Fv′/Fm′). Likewise, EBR increased the fraction of photochemical efficiency (P) and reduced the fraction of antenna heat dissipation (D) and excess energy (E). Low temperature led the increase in end product of lipid peroxidation and the content of H2O2, O2− and OH−, and it caused the occurrence of oxidative stress. The activities of antioxidative enzymes including superoxide dismutase, peroxidase, catalase and ascorbate peroxidase, and contents of ascorbic acid and reduced glutathione were significantly improved by EBR during low temperature stress. The application of EBR also markedly increased the contents of proline, soluble sugar and protein under low temperature. EBR significantly reinforced antioxidant defense system, and it can be reflected through the reduced accumulation of harmful reactive oxygen species and MDA in pepper seedlings. Overall, these results suggest that EBR increases the tolerance of pepper seedlings against chilling stress largely by optimizing distribution of absorbed energy and excitation energy and enhancing antioxidant defense system.

Research on Biological Materials for the Preferred of the Chlorophyll Content Gray GM (1,1) Prediction Models Based on the Different Light

Light is one of the most important factor in the growth of plants, with the advent and application of biological materials such as different artificial LED source, the new agricultural technology has been rapid development. In this study, first established the gray GM (1,1) prediction model of the pepper seedlings chlorophyll changes under the different light and then compared of the chlorophyll models under the different light. Last the study found that different artificial LED have the different effect and the forecasting curve and prediction model under the blue is optimal for pepper seedling by comparing the chlorophyll curves and predictive models of pepper seedlings under different light, so blue light is the most suitable for the growth of pepper seedlings. The results turned out that accuracy test of the three gray prediction models can achieve the best grade, and the three gray prediction models have the good practical value. Grey prediction theory can be better applied to the study of the plants.

The Growth of Root Rot Disease on Pepper Seed Applied by Trichoderma Harzianum Inoculum

Normal 0 false false false IN X-NONE X-NONE MicrosoftInternetExplorer4 Root rot disease on pepper caused by Phytophthora capsici is one of the most important diseases on pepper. The using of antagonistic fungus of Trichoderma harzianum as a biological control agent of the pathogen is one of the important alternatives in controlling P. capsici without causing negative effects on the environment. The objectives of the research were to study about the ability of T. harzianum inoculum application in inhibiting the development of root-rot disease, influenced the growth of pepper seed, to studythe effective length time application of T. harzianum inoculum in inhibiting the development of root rot disease, and increased the growth of pepper seedlings. This research was arranged in a completely randomized design, with five treatments of length time application of T. harzianum inoculum i.e. control treatment without applicationtime of T. harzianum inoculum (K), application time of T. harzianum inoculum for 0 week (S0), application time of T. harzianum inoculum for 1 week (S1), application time of T. harzianum inoculum for two weeks (S2), application time of T. harzianum inoculum for three weeks (S3), and application time of T. harzianum inoculum for 4 weeks (S4) before planting. Each treatment was repeated15 times. The observed parameterswere disease percentage, the inhibition of antagonistic fungus, disease infection rate, plant height, number of leaves, wet and dry weight of plant, stem and leaves on pepper seed, and P. capsici population density. The result showed that application time of T. harzianum inoculumfor 4 weeks (S4) before planting is the most effective time in inhibiting the development of root rot disease than the other treatment sand also had significant effect on increasing the growth of pepper seed. The antagonism test showed that T. harzianum could inhibit P. capsiciin vitro. This result proves that application time of T. harzianum inoculums for 4 weeks (S4) before planting is more effective in inhibiting the development of root rot disease and able to increase the growth of pepper seed Normal 0 false false false IN X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Doi : 10.12777/ijse.5.1.49-54 [ How to cite this article : Sofian, B. Hadisutrisno , A. Priyatmojo . (2013). The Growth of Root Rot Disease on Pepper Seed Applied by Trichoderma Harzianum Inoculum . International Journal of Science and Engineering , 5(1):49-54. Doi: 10.12777/ijse.5.1.49-54 ] /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} <w:LsdException Locked="false" Priority="29" SemiHidden="false" UnhideWhenUsed="false" QFormat="true" N

Effect of Soil Nursery Mixtures on the Growth of Pepper Seedlings in Owerri, South Eastern Nigeria

This study was undertaken to determine the best nursery medium for raising seedlings of pepper in a tropical rainforest location of Owerri, south eastern Nigeria. The experiment was carried out in the teaching and research farm of the department of Agricultural Science, Alvan Ikoku Federal College of Education, Owerri. The design used was completely randomized design (CRD) with five replications. A total of six different soil mixtures (treatment) were used in the study. Treatments comprised soil nursery mixtures in the ratio of 0:3:3, 1:2:3, 1:3:2, 2:3:1, 3:2:1 and 2:1:1 for poultry manure: top soil: river sand. Data was collected on percentage seedling emergence, plant height, leaf area per plant, dry matter weight per plant at 42DAP.Analysis of variance test was conducted on all data collected. Significant treatment means were separated by means of F-LSD. Results showed that treatment 3:2:1 significantly (p-0.05) produced highest values in all the parameters studied and is therefore recommended for raising pepper in this tropical rain forest location of Owerri, south eastern Nigeria.

Salinity and Soil Type Effects on Emergence and Growth of Pepper Seedlings

High soil salinity often results in poor stand establishment, reduced plant growth, and reduced yield of many horticultural crops such as peppers (Capsicum annuum). We investigated the effects of soil salinity and soil type on seedling emergence and growth of four commercial peppers (‘NuMex Joe E. Parker’, ‘NuMex Nematador’, ‘NuMex Primavera’, and ‘Jupiter’) in greenhouse experiments. Seeds were sown in either a loamy sand or a silt loam soil in pots and irrigated with saline solutions at electrical conductivity of 0.9 (tap water), 3.0, or 6.0 dS·m−1 (Expt. 1) or at 0.0 [reverse osmosis (RO) water], 0.9, or 1.5 dS·m−1 (Expt. 2). No seedling emergence was observed in treatments irrigated with 3.0 or 6.0 dS·m−1 solutions. The salinity at the top soil layer increased linearly with time when subirrigated with tap and saline solutions in both soil types, whereas no substantial increase in soil salinity was found when subirrigated with RO water or overhead irrigation with tap water. Salt accumulation at the top soil layer was greater in loamy sand than in silt loam. Seedling emergence percent subirrigated with RO water ranged from 70% to 80% in loamy sand and 45% to 70% in silt loam, depending on pepper cultivars. When subirrigated with tap water and saline solutions, the emergence percent ranged from 0% to 60%, depending on pepper and soil types. In Expt. 3, seedlings were germinated in commercial potting mix and grown in 1.8-L pots containing commercial potting mix. Saline solution treatments of 1.4 (control, nutrient solution), 2.1, 2.9, 3.5, or 4.2 dS·m−1 were initiated when seedlings had 11 to 13 leaves. Five weeks after initiating saline water irrigation, the reduction in shoot dry weight was greater in ‘Jupiter’ and ‘NuMex Primavera’ as compared with ‘NuMex Joe E. Parker’ and ‘NuMex Nematador’, but the differences were small.

Gas Exchange, Water Status, and Growth of Pepper Seedlings Exposed to Transient Water Deficit Stress are Differentially Altered by Antitranspirants

Successful field establishment of vegetable transplants often depends on the ability of young seedlings to tolerate various biotic and abiotic stresses after transplanting. Treatments that limit transpirational water loss could improve plant survival and stand establishment. In this study we evaluated growth and physiological responses of pepper (Capsicum annuum L.) seedlings to foliar application of chemical plant regulators [abscisic acid (ABA) and aminoethoxyvinylglycine (AVG)] or physical film-forming barriers [AntiStress (AS), Transfilm (TF), and Vapor Gard (VG)] during transient 4-day water deficit cycles. During two 4-day water deficit cycles, stomatal conductance (g s) and net CO2 assimilation rate (ACO2) were unaffected by the application of physical materials, but differed for ABA and AVG. Compared with untreated control plants, ABA reduced g s (47% to 69%) and ACO2 (37% to 57%) by the end of the second water deficit cycle, whereas AVG increased gs (27% to 60%) during the first desiccation cycle. Leaf (ψlf) and stem (ψst) xylem water potential of plants treated with film-forming materials generally decreased at the same rate as those of untreated plants, whereas application of AVG caused earlier and more pronounced decline of ψlf. Application of ABA enabled the maintenance of ψlf and ψst during two desiccation cycles, and thus prevented an increase of electrolyte leakage and leaf abscission. Growth rates of all plant components were reduced after ABA applications. However, allometric relationships showed similar patterns of dry matter allocation in leaves and shoots among ABA, TF, VG, and untreated control plants. Application of AS reduced allocation of dry matter to leaves, whereas AVG enhanced it at the expense of roots. These data indicate that water deficit tolerance of pepper seedlings only occurred with foliar application of ABA. This effect was associated with improved plant water relations, increased cell membrane stability, reduced leaf abscission, and a transient reduction in plant growth rates.

Growth enhancement and Phytophthora blight ( Phytophthora capsici Leonian) control by arbuscular mycorrhizal fungal inoculation in pepper

The effects of selected arbuscular mycorrhizal (AM) fungi, Glomus mosseae, Glomus etunicatum, Glomus fasciculatum and Gigaspora margarita, on growth of pepper seedlings and Phytophthora blight caused by Phytophthora capsici and the role of the phytoalexin, capsidiol were investigated. Root colonization by AM fungi reached between 61.3% and 68.1% in roots of pepper 4 weeks after transplanting. All tested AM fungi increased the shoot height between 23.4% and 31.7% and fresh and dry weights of shoots and roots of plants were enhanced by G. etunicatum, G. fasciculatum and Gigaspora margarita compared to uninoculated plants in pot experiments. G. fasciculatum increased yield significantly by 22% under greenhouse conditions. G. mosseae reduced the disease severity of P. capsici by 91.7%, 43.0% and 57.2% under pot, greenhouse and field conditions, respectively. Compared to the control, the capsidiol level was increased by preinoculation with G. mosseae and in the necrotic stems of P. capsici-inoculated pepper plants. In conclusion, AM fungi, especially G. mosseae enhanced the development of plants and reduced Phytophthora blight of pepper.

Response of Rockwool-grown Greenhouse Cucumber, Tomato, and Pepper to Kinetin Foliar Sprays

Encouraging results from previous trials on field vegetables led to the expectation that a kinetin foliar spray from the commercial product KIN-Gro (5000 ppm kinetin) on greenhouse vegetables would positively affect their growth and productivity. Thus, in this study, we evaluated the usefulness of this product on rockwool-grown `Bodega' cucumber (Cucumis sativus), `Rapsodie' tomato (Lycopersicum esculentum), and `4-Ever' and `444' pepper (Capsicum annuum) at the Greenhouse and Processing Crops Research Centre of Agriculture and Agri-Food Canada, Harrow, Ont. Two replicated experiments were conducted to study the effect of kinetin spray on growth and production of all three crops: the first in Spring-Summer 2004 and the second in Fall-Winter 2004. Foliar sprays of kinetin at 2.5, 5, and 10 ppm concentrations were tested against a water spray (control) on each crop. A 2.5-ppm kinetin spray had beneficial effects on the growth of cucumber transplants (taller plants and greater leaf area and fresh weight of leaves and stems). Furthermore, this treatment resulted in higher marketable yield in the Spring-Summer crop and in larger fruit size in the Fall-Winter crop. Regression analysis showed that cucumber marketable yield had an overall quadratic response to kinetin spray concentration in Spring-Summer season maximizing at 5.1 ppm kinetin. Kinetin spray also had beneficial effects on the growth of tomato seedlings, but not on yield. On the other hand, significant beneficial effects were observed on the growth of pepper seedlings and on marketable yield and fruit quality. Regression analysis showed that the response of pepper marketable yield to kinetin spray concentration was positive and linear. It must be noted that, given the rather short-term nature of our experiments, the observed beneficial effects of the kinetin sprays on yield can only be interpreted as beneficial effects on early yield rather than on the total yield. We concluded that under our growing conditions, cucumber production would benefit from a dilute (2.5 ppm) kinetin spray, and pepper production from a high concentration spray (10 ppm); tomato transplant growth will also benefit from a kinetin spray at 2.5 ppm. The results of this study could be of considerable significance to the greenhouse vegetable industry.

Effects of two plant growth-promoting Rhizobacteria on the germination and growth of pepper seedlings (Capsicum Annum) CV. Roxy: Wirkung von zwei wachstumsfordernden Rhizobakterien auf die keimung und das wachstum von pfeffersaaten (Capsicum Annum) CV. Roxy

The effect of two plant growth-promoting rhizobacteria (PGPRs) on the germination and growth of pepper seedlings was investigated in a culture chamber. The two strains showed metabolic capacities related to their potential PGPR action. Two different patterns of inoculation were carried out. In the first, strains were inoculated when seeds were sown, and in the second when seedlings showed fully developed cotyledons. In both cases the following parameters were measured: aerial and root surface, aerial and root length and aerial and root weight. In the first pattern of inoculation no aerial parameters were modified, probably because the bacteria did not colonize the root. In the second pattern of inoculation, all parameters were significantly modified by Chryseobacterium balustinum, except root surface, which indicated that this bacterium was able to colonize the root. Serratia fonticola did not modify any parameter. In both inoculation patterns root length was reduced by both bacteria probably due to a hormonal effect. C. balustinum enhanced aerial surface, aerial length and also the dry aerial and root weight. This resulted in stronger and more robust plants with a higher adaptative capacity and a greater resistance against pathogens.

Regulation of Bell Pepper Seedling Growth with End-of-day Supplemental Fluorescent Light

The influence of end-of-day (EOD), supplemental, cool-white fluorescent light on pepper (Capsicum annuum L. cv. Keystone Resistant Giant No. 3) seedling growth and fruit production after transplanting to the field was investigated. Seedlings were exposed to this light source, which is high in the red wavebands, from one (1988) or two bulbs (1989) for 1 hour before the end of the natural photoperiod. Each year control plants were exposed to ambient light and received no supplemental fluorescent light. Before transplanting to the field, seedlings exposed to two bulbs were shorter and had smaller leaves than plants in the control treatment. Supplemental fluorescent light treatment, regardless of number of bulbs, reduced plant height, leaf area, fruit weight, and fruit count at the first harvest. Total fruit production was not affected by supplemental light, suggesting no residual effect of the light treatment during transplant production on total subsequent fruit production.

Bell Pepper Seedling Growth and Yield following Pretransplant Nutritional Conditioning

To reduce transplant shock of bell peppers (Capsicum annuum L.), we tested the effectiveness of pretransplant nutritional conditioning (PNC) as a promoter of earliness and yield. In Expt. 1, `Gatorbelle' bell pepper seedlings were fertilized with N from Ca(NO3)2 at 25, 75, or 225 mg·liter-1 and P from Ca(H2PO4)2 at 5, 15, or 45 mg·liter-1. Nitrogen interacted with P, affecting shoot fresh and dry weight, leaf area, root dry weight, seedling height, and leaf count. In Expt. 2, transplants conditioned with N from 50, 100, and 200 mg·liter-1 and P at 15, 30, and 60 mg·liter-1 were field-planted in Charleston, S.C., and Clinton, N.C. Nitrogen- and P-PNC did not greatly affect recovery from transplant shock. Although N- and P-PNC affected seedling growth in the greenhouse, earliness, total yield, and quality were similar in field studies among all PNC treatments at both locations. PNC with 50 mg N and 15 mg P/liter can be used with this variety and not have any long-term detrimental effects on yield and quality.

Supplemental Carbon Dioxide and Light Improved Tomato and Pepper Seedling Growth and Yield

The experiment was conducted to determine the effects of CO, enrichment (900 μl·liter-1, 8 hours/day) in combination with supplementary lighting of 100 μmol·s-1·m-2(16-h photoperiod) on tomato (Lycopersicon esculentum Mill.) and sweet pepper (Capsicum annuum L.) seedling growth in the greenhouse and subsequent yield in the field. Enrichment with CO2 and supplementary lighting for ≈ 3 weeks before transplanting increased accumulation of dry matter in shoots by ≈ 50% compared with the control, while root dry weight increased 49% for tomato and 6270 for pepper. Early yields increased by =1570 and 11% for tomato and pepper, respectively.