Total Shoot Research Articles

Optimizing tiller production and survival for grain yield improvement in a bread wheat × spelt mapping population.

Tiller production and survival determine final spike number, and play key roles in grain yield formation in wheat (Triticum aestivum). This study aimed to understand the genetic and physiological basis of the tillering process, and its trade-offs with other yield components, by introducing genetic variation in tillering patterns via a mapping population of wheat × spelt (Triticum spelta). The dynamics of tillering and red/far-red ratio (R:FR) at the base of a canopy arising from neighbouring plants in a bread wheat (Triticum aestivum 'Forno') × spelt (Triticum spelta 'Oberkulmer') mapping population were measured in the field in two growing seasons. Additional thinning and shading experiments were conducted in the field and glasshouse, respectively. Yield components were analysed for all experiments, followed by identification of quantitative trait loci (QTL) associated with each trait. Large genetic variation in tillering was observed, and more fertile shoots per plant were associated with more total shoots initiated, faster tillering rate, delayed tillering onset and cessation, and higher shoot survival. A total of 34 QTL for tillering traits were identified, and analysis of allelic effects confirmed the above associations. Low R:FR was associated with early tillering cessation, few total shoots, high infertile shoot number and shoot abortion, and these results concurred with the thinning and shading experiments. These effects probably resulted from an assimilate shortage for tiller buds or developing tillers, due to early stem elongation and enhanced stem growth induced by low R:FR. More fertile tillers normally contributed to plant yield and grain number without reducing yield and grain set of individual shoots. However, there was a decrease in grain weight, partly because of smaller carpels and fewer stem water-soluble carbohydrates at anthesis caused by pleiotropy or tight gene linkages. Tillering is under the control of both genetic factors and R:FR. Genetic variation in tillering and tolerance to low R:FR can be used to optimize tillering patterns for yield improvement in wheat.

Uso da subirrigação para imposição de estresse hídrico em sistema semi-contínuo para medição de CO2

The objectives of this work were to evaluate the effects of distinct moisture contents to trigger subirrigation on salvia photosynthesis and plant growth, and to verify the feasibility of subirrigation use in water stress imposition research in this crop. We evaluated two substrate volumetric water contents (VWC) as treatments (0.2 and 0.4 m3 m-3) to trigger subirrigation, with 4 replications. Each replication was composed of 10 plants. An automated semi-continuous multi-chamber crop CO2-exchange system was used, with capacitance soil moisture sensors for continuous moisture monitoring. Manual subirrigation with nutrient solution was performed when VWC dropped below the thresholds. In both treatments, the values of net photosynthesis, daily carbon gain and carbon use efficiency reduced over time, from 2 to 1.1 μmol s-1 from 2.2 to 1 μmol d-1 from 0.7 to 0.45 mol mol-1, respectively, in both soil moisture treatments. Total shoot dry mass (p=0.0129), shoot height in the tip of the highest flower (p<0.0001) and total leaf area (p=0.0007) were statistically higher at 0.4 m3 m-3 treatment. The subirrigation system was not efficient to impose water stress, due to excessive variation on VWC values after each irrigation event in both treatments. Higher soil moisture promoted positive plant growth responses in salvia cultivated by subirrigation.

Effect of Arbuscular Mycorrhizal Fungi On Yield and Phytoremediation Performance of Pot Marigold (Calendula officinalis L.) Under Heavy Metals Stress

In order to study the effect of mycorrhizal fungi (inoculated and non-inoculated) and heavy metals stress [0, Pb (150 and 300 mg/kg) and Cd (40 and 80 mg/kg)] on pot marigold (Calendula officinalis L.), a factorial experiment was conducted based on a randomized complete block design with 4 replications in Research Greenhouse of Department of Horticultural Sciences, University of Tehran, Iran, during 2012–2013. Plant height, herbal and flower fresh and dry weight, root fresh and dry weight and root volume, colonization percentage, total petal extract, total petal flavonoids, root and shoot P and K uptakes, and Pb and Cd accumulations in root and shoot were measured. Results indicated that with increasing soil Pb and Cd concentration, growth and yield of pot marigold was reduced significantly; Cd had greater negative impacts than Pb. However, mycorrhizal fungi alleviated these impacts by improving plant growth and yield. Pot marigold concentrated high amounts of Pb and especially Cd in its roots and shoots; mycorrhizal plants had a greater accumulation of these metals, so that those under 80 mg/kg Cd soil−1 accumulated 833.3 and 1585.8 mg Cd in their shoots and roots, respectively. In conclusion, mycorrhizal fungi can improve not only growth and yield of pot marigold in heavy metal stressed condition, but also phytoremediation performance by increasing heavy metals accumulation in the plant organs.

Dynamics of shoot and fruit growth following fruit thinning in olive trees: Same season and subsequent season responses

The need to understand how the balance between vegetative and reproductive growth in olive trees is modified by different crop loads has become more important over the last 20 years due to increasing planting densities and the greater use of irrigation. The objectives of this study conducted in a well-irrigated olive orchard were to: (1) evaluate shoot and fruit growth dynamics following fruit thinning during the same growing season in which thinning was applied and during the next growing season; and to (2) determine crop load effects on bloom, fruit set, and fruit yield over three growing seasons. Hand-thinning of fruit 35 days after full bloom on 9-year-old cv. ‘Arauco’ trees in an “on” year led to thinning treatments of 24, 48, and 87% with respect to an unthinned control. Apical and lateral shoot elongation were measured every two weeks throughout the growing season, and fruit were sampled to determine fruit weight at the same interval. Apical shoot elongation occurred only early in the season when crop load was medium or high, while apical elongation continued for most of the season when crop load was low. Elongation of laterals contributed significantly to total shoot elongation on fruit-bearing branches in trees with low crop loads after thinning the first season. Individual fruit dry weight was reduced about 40% by high crop loads in both seasons. Differences in relative growth rates of both the shoots and the fruit due to crop load suggest fruit growth was limited by photoassimilate availability early in the season, but shoot growth was limited most of the season under medium and high crop loads. Inflorescence number per shoot was reduced by crop load in the two seasons following the thinning event. Fresh fruit yield was only reduced in one of the two biennia (i.e., periods of 2 years) in the trees that were heavily thinned (87%) the first season. The trees in which about one-half (48%) of the fruit were thinned the first season did not show biennia yield reductions and maintained a low alternate bearing index over three seasons. Thus, chemical thinning could be applied in growing seasons with high flowering. Further studies are needed to better assess competition for resources between shoots and fruit with the ultimate goal of reducing alternate bearing.

Early Vigor of Advanced Breeding Lines and Modern Cotton Cultivars

ABSTRACTStand establishment and early vigor are critical to the successful production of cotton (Gossypium hirsutum L.). Rapid early growth could provide significant advantages to young plants relative to diseases, insects, and weeds. The objectives of this research were to identify traits that contribute to differences in early growth, characterize genotypic variation in early vigor among modern cultivars and advanced breeding lines, and determine the effect of the seed production environment on early vigor. Early growth of 10 genotypes from private companies and 18 unreleased breeding lines was compared through measurements of leaf area and biomass under field conditions in 2 yr. A positive correlation of seed weight and rapid early growth was observed up to 32 d after planting (DAP). Cotyledon area was positively associated with shoot dry weight over the course of the first 52 DAP. Significant genotypic differences were observed for cotyledon and total leaf areas, and for cotyledon, first true leaf, total leaf, stem, and total shoot dry weights in both years within approximately the first 4 wk after planting. No correlation between lint yield and rapid early growth was found. For the first 17 (2009) and 32 (2008) DAP—but not after that—plants grown from seeds produced in distinct environments differed in early vigor. Overall, seeds from breeding lines produced more vigorous seedlings than did seeds of commercial genotypes. Although heritability of the examined traits has not been established, the broad range in values and significant genotypic variation suggest that breeding for enhanced early vigor should be possible without compromising yield.

Unexpected relationships between vine vigor and grape composition in warm climate conditions

<p style="text-align: justify;"><strong>Aim</strong>: The purpose of the research was to link vigor with grape composition in a climate change scenario.<strong></strong></p><p style="text-align: justify;"><strong>Methods and results</strong>: This work presents a 4-year study (from 2010 to 2013) in a non-irrigated Tempranillo vineyard located in La Rioja (Spain). It is based on the acquisition of multi-spectral imagery at <em>véraison</em> and a subsequent zoning in two different vigor zones based on NDVI (Normalized Difference Vegetation Index). All parameters related to vigor showed significant differences within the zones (total shoot length, leaf area, pruning weight). Unexpectedly, the content in anthocyanins was found to be higher in the highest vigor zone in most of the years of study, a point particularly discussed in this work.<strong></strong></p><p style="text-align: justify;"><strong>Conclusion</strong>: Climatic conditions may affect considerably bunch microclimate and disturb the biosynthetic pathways of major grape components, leading to maturation mismatches. In hotter years, high vigor vines may favor anthocyanin accumulation through shading and protecting effects in the bunch area.</p><strong>Significance and impact of the study</strong>: Many studies have shown a negative relationship between vigor and grape anthocyanins, but in the present research the opposite trend was observed in hot years.

Seasonal dynamics of biomass partitioning in a tall sedge, Carex acuta L.

The demographic and production characteristics were investigated in Carex acuta L., a common dominant of temperate herbaceous wetlands. The seasonal courses of shoot density and biomass were followed in a model population using the method of successive harvests for eight years. Destructive and non-destructive types of measurement were combined in order to study the biomass turnover at the level of single shoots. Belowground biomass was estimated from soil blocks and related to shoot density. The seasonal maximum of total aboveground biomass varied from 400 to 750gm−2, of which C. acuta formed 25–90%. Vegetative shoots accounted for 90% of the total shoot density and 95% of the species’ aboveground biomass. They invested about 90% of their annual production to leaf blades; new leaves were produced from early spring to top summer and increased their dry weight until late autumn. The generative shoots allocated about 2/3 of their annual production to the stem with inflorescence. They grew fast in spring but died off soon after seed maturation in July. The annual production was 2.7g and less than 2.0g dry weight for vegetative and generative tillers, respectively. The turnover rates, reflecting the dry weight of leaves lost during the vegetation season, were 1.2–1.3 year−1 and 1.0–1.1 year−1 for vegetative and generative shoots, respectively. Leaves had a smaller dry weight and a smaller specific leaf mass after, than before their death. This difference, which was ascribed to the downward re-translocation of mobile materials, accounted for 20% dry weight of the leaves prior to dying out. Roots formed about 90% of the live belowground biomass. The average root dry weight was about 2g per shoot in spring and summer and increased to about 5g per shoot by the end of the vegetation season. The annual aboveground primary production of C. acuta can be underestimated by about 1/3 if the turnover rate and downward re-translocation are not considered.

Plant regeneration from shoot regrowth and de novo embryo-like structures from cryopreserved shoot tips of Lilium spp.

Plant regeneration via both shoot regrowth and de novo embryo-like structures was obtained from cryopreserved shoot tips of Lilium spp. Shoot tips (1.0–3.0 mm in length) of Lilium Oriental hybrid ‘Siberia’ containing two- to four-leaf primordia were excised from 4-wk-old adventitious shoots and cryopreserved by droplet vitrification. When post-cultured for 6 wk on recovery medium containing 0.1 mg/l α-naphthaleneacetic acid (NAA) in combination with different kinetin (KT) concentrations (0–0.4 mg/l), three types of regenerants were produced: (1) only embryo-like structures, (2) shoot regrowth with embryo-like structures, and (3) only shoot regrowth. The highest frequencies (≥75.0%) of total embryo-like structures were obtained from cryopreserved shoot tips post-cultured on recovery medium containing 0.1 mg/l NAA and 0.1–0.2 mg/l KT. Embryo-like structures proliferated within 4 wk of culture on medium containing 1.0 mg/l NAA and 0.05 mg/l thidiazuron (TDZ). Somatic embryo-like structures matured and converted into whole plantlets after 8 wk of culture on Murashige and Skoog (MS) medium without any plant growth regulators. The highest frequencies (≥25.0%) of total shoot regrowth were produced from cryopreserved shoot tips post-cultured on recovery medium containing 0.1 mg/l NAA and 0.05–0.4 mg/l KT. With the protocols reported here, frequencies of total embryo-like structures and shoot regrowth ranged from 45.0 to 90.0% and 25.0 to 52.5%, respectively, from six lily varieties belonging to five Lilium species or hybrids, representing diverse Lilium germplasm. The results reported here have potential applications to long-term conservation of genetic resources and genetic transformation in Lilium spp.

Arbuscular mycorrhizal symbiosis alters the expression patterns of three key iron homeostasis genes, ZmNAS1, ZmNAS3, and ZmYS1, in S deprived maize plants.

Nicotianamine is an essential molecule for Fe homeostasis in plants, its primary precursor is the S-containing compound methionine, and it is biosynthesized by the enzyme family of nicotianamine synthases (NASs). In maize, a graminaceous plant that follows Strategy II for Fe uptake, ZmNAS genes can be subgrouped into two classes, according to their roles and tissue specific expression profiles. In roots, the genes of class I provide NA for the production of deoxymugineic acid (DMA), which is secreted to the rhizosphere and chelates Fe(III). The Fe(III)-DMA complex is then inserted to the root via a ZmYS1 transporter. The genes of class II provide NA for local translocation and detoxification of Fe in the leaves. Due to the connection between S and Fe homeostasis, S deficiency causes Fe deprivation responses to graminaceous plants and when S is supplied, these responses are inverted. In this study, maize plants were grown in pots with sterile river sand containing FePO4 and were inoculated with the mycorrhizal fungus Rhizophagus irregularis. The plants were grown under S deficient conditions until day 60 from sowing and on that day sulfate was provided to the plants. In order to assess the impact of AM symbiosis on Fe homeostasis, the expression patterns of ZmNAS1, ZmNAS3 (representatives of ZmNAS class I and class II), and ZmYS1 were monitored before and after S supply by means of real time RT-PCR and they were used as indicators of the plant Fe status. In addition, total shoot Fe concentration was determined before and after S supply. AM symbiosis prevented Fe deprivation responses in the S deprived maize plants and iron was possibly provided directly to the mycorrhizal plants through the fungal network. Furthermore, sulfate possibly regulated the expression of all three genes revealing its potential role as signal molecule for Fe homeostasis.

Effects of Preconditioning Through Mycorrhizal Inoculation on the Control of Melon Root Rot and Vine Decline Caused by Monosporascus cannonballus

AbstractThe use of inoculum of arbuscular mycorrhizal fungi (AMF) in nursery represents a promising field in horticulture because of its known benefits in terms of plant growth and bioprotection. The present work was undertaken to determine the effect of mycorrhizal inoculation with Rhizophagus irregularis in a nursery medium on the containment of melon root rot and vine decline (MRRVD) caused by the soil‐borne pathogen Monosporascus cannonballus. The percentage of mycorrhization, biomass and yield following mycorrhizal inoculation were also evaluated. Biocontrol activity was assessed in greenhouse pot experiments upon artificial inoculation of M. cannonballus and in a two‐season field experiment under production conditions in an unheated greenhouse with a history of MRRVD. On the basis of the mycorrhization parameters, the interaction appeared to be established within 30 days after inoculation. The total shoot growth in the mycorrhized plants was significantly higher when compared to the control, while the root growth was unaffected. Upon artificial inoculation of M. cannonballus, mycorrhization provided complete protection against the pathogen. Greenhouse experiments under production conditions during spring cropping season showed that pretransplanting inoculation with R. irregularis significantly decreased the severity of the disease. Also, the average fruit weight of mycorrhized plants was significantly higher than the untreated control. Nevertheless, in summer crop, the bioprotection activity of AMF failed. Present results indicate that the use of AMF in a nursery setting can contribute to the prevention of the onset of this problematic soil‐borne disease within a sustainable and integrated soil‐borne disease management.

Subsoil compaction and irrigation regimes affect the root–shoot relation and grain yield of winter wheat

The combined effects of soil moisture and physical parameters are important concerns in crop production. A three-season field experiment and a two-season tube experiment were performed to examine the effects of subsoil bulk density (BD) on the performance of winter wheat associated with irrigation regimes. Tubes (19.2cm in inner diameter and 1m in depth) were compacted with soil to create different BD ranging from 1.4 to 1.8g/cm3 at a subsoil layer (20–40cm). The field study was conducted under deep tillage (DT) and rotary tillage (RT) that created two different BD at the subsoil layer (1.57 and 1.67g/cm3, respectively). Two irrigation regimes (deficit and adequate) were applied to both the field and the tube experiments. Results from the tube tests showed that total root weight (TRW) was reduced with the increase in the BD, especially the root weight under the subsoil pan. TRW was positively related to the total shoot weight; whereas the final grain yield was not linearly related to the shoot weight, due to the different effects of BD and irrigation on harvest index. Moderate subsoil BD (1.5–1.6g/cm3) produced the highest harvest index and grain yield. Results from the field experiment showed that the lower subsoil BD under DT improved the root growth in the deep soil layer, resulting in more soil water utilization under deficit irrigation, as compared with the higher subsoil BD under RT. Thus the yield under DT was improved under deficit irrigation. No significant difference in yield under adequate irrigation was found between the two tillage methods. The results testified that the effects of subsoil compaction on crop performance were associated with soil water conditions. Under relative dry condition, higher than optimum subsoil BD would negatively affect crop performance more significantly than that under sufficient water supply. The subsoil BD should be maintained below 1.6g/cm3 under the growing conditions of this study. The long-term RT had increased the subsoil BD over this limit. Optimizing the subsoil BD by tillage management would benefit crop production.

English

The aim of this work was to test fertilizers, liming, and levels of a soil conditioner produced from leonardite, composed by humic and fulvic acids on “iceberg” lettuce growth characteristics. The experimental design was completely randomized in a 5×3×2 factorial scheme, with 5 levels of soil conditioner (0, 20, 40, 100 and 200 L ha-1), 3 fertilizers [chicken manure, plant compost (plant residues and cattle manure) and mineral], in limed and unlimed soil, with five replicates. The experiment was carried out in a greenhouse. Total shoot fresh and dry weight, shoot commercial fresh and dry weight, plants height, circumference, and number of leaves were evaluated as well as final soil pH and nutrient levels in leaves. Chicken manure rendered the greater circumference and shoot fresh commercial weight. Lettuce produced with chicken manure presented higher content of P, Ca, and Mg in leaves. Soil conditioner, in general, did not influence plant growth, except in its height, in the highest applied dose. With absence of lime, soil conditioner caused an increase of lettuce height with mineral fertilizers, and a decrease with plant compost.   Key words: Humic substances, Lactuca sativa L., chicken manure, compost.

INTEGRATED PLANT NUTRITION ON THE RECOVERY OF A PEAR (PYRUS COMMUNIS 'PACKAM'S TRIUMPH') ORCHARD

The use of organic matter for recovering decayed orchards is getting increased attention in Chile, considering that chemical fertilization alone does not cause the expected effects. Integrated plant nutrition (IPN) is a concept in which organic matter, in combination with chemical fertilization, stimulate the rhizogenesis process and therefore improve plant nutrition. During the 2011/12 and 2012/13 growing seasons, an experiment was performed to evaluate the effects of IPN on the recovery of decayed pear trees (Pyrus communis ‘Packam’s Triumph’), in Peumo, Rapel Valley, Chile. Two treatments were compared in a factorial experiment, using a randomized design, with four replications. The IPN treatment consisted on the application of 20 ton/ha of compost, together with chemical fertilization NPK per season, respectively; control treatment included only the chemical fertilization at the same rates. Compost was produced from grape pomace and, on the average, had 20% C, a C/N ratio: 16:1; N-NO3/N-NH4=1,23 and a low content of trace elements, with the exemption of Cu which showed values above the Chilean standard limits (NCh 2880/04) for compost type A. Compost was applied once each season, in band, during winter time (July), while chemical fertilization was applied during the growing season from October to February. Evaluations included root density; total shoot growth; enzymatic activity in soil; Mineral leaf contents; Normalized Difference Vegetation Index (NDVI), and SPAD readings. Results showed significant differences (p<0.05) between treatments for: root density, pruning weight, enzymatic activity in soil, NDVI, SPAD readings, Na, Zn and Cu leaf contents and nutrient indices for N, K, Ca, Mg, Cu and Zn, which were larger for the IPN management. Integrated plant nutrition seems to be the way to recover decayed orchards through the inclusion of good quality organic matter within the management program.

Foliar application of microbial and plant based biostimulants increases growth and potassium uptake in almond (Prunus dulcis [Mill.] D. A. Webb).

The use of biostimulants has become a common practice in agriculture. However, there is little peer-reviewed research on this topic. In this study we tested, under controlled and replicated conditions, the effect of one biostimulant derived from seaweed extraction (Bio-1) and another biostimulant derived from microbial fermentation (Bio-2). This experiment utilized 2-years-old almond plants over two growing seasons in a randomized complete design with a full 2 × 4 factorial structure with two soil potassium treatments (125 μg g-1 of K vs. 5 μg g-1) and four foliar treatments (No spray, Foliar-K, Bio-1, Bio-2). Rubidium was utilized as a surrogate for short-term potassium uptake and plant growth, nutrient concentration, and final plant biomass were evaluated. There was a substantial positive effect of both biostimulant treatments on total shoot leaf area, and significant increases in shoot length and biomass under adequate soil potassium supply with a positive effect of Bio-1 only under low K supply. Rubidium uptake was increased by Bio-1 application an effect that was greater under the low soil K treatment. Though significant beneficial effects of the biostimulants used on plant growth were observed, it is not possible to determine the mode of action of these materials. The results presented here illustrate the promise and complexity of research involving biostimulants.

Use of 15n labelled urea to quantify nitrogen recovery studies and effect of salinity on rice

An experiment was conducted to study the effects of salinity, and fertilisation on wetland rice production. It was a factorial design with four levels of salinity and three levels of fertilisation. Rice plants were grown in wetland system under greenhouse conditions. Fertiliser treatments were imposed at planting. Following germination salinity treatments were imposed. Plants and soils were sampled 10 weeks after planting. Plant dry weight increased with increasing inorganic fertiliser application and decreased with increasing salinity. Total shoot N increased with increasing inorganic fertiliser application but was not affected by salinity, however total root N increased with increasing inorganic fertiliser addition and decreased with increasing level of salinity (0, 50 and 100 ppm). Plant dry weight decreased with increasing salinity. Plant dry weight and N contents in shoot and root were significantly higher in all inorganic fertiliser treatments compared to the control treatments. % Ndff was in the range of 30-50 % and increased with increasing fertiliser application and salinity. Fertiliser use efficiency was in the range of 67.87-72.8 % in the inorganic fertiliser treatment. DOI: http://dx.doi.org/10.3329/bjsir.v49i2.21998 Bangladesh J. Sci. Ind. Res. 49(2), 69-78, 2014

Optimum Crop Load in Different Planting Densities of Adult ‘Fuji’/M.9 Apple Tree for Preventing Biennial Bearing and Stabilizing Tree Vigor

본 시험은 성목기 '후지'/M.9 사과나무의 재식밀도별 적정 착과수를 조사하고자 영양생장, 생산량, 과실품질 및 이듬해 개화율을 3년(재식 7-9년차) 동안 조사하였다. 시험재료는 <TEX>$3.5{\times}1.5m$</TEX>(190주/10a), <TEX>$3.5{\times}1.2m$</TEX>(238주/10a), <TEX>$3.2{\times}1.2m$</TEX>(260주/10a)로 심어 세장방추형을 목표수형으로 관리하고 있는 '후지'/M.9 사과나무이었다. 목표 착과수 범위는 주당 55-64과, 65-74과, 75-84과, 85-94과, 95-104과의 5수준이었다. TCA 증가, 총 신초장, 이듬해 개화율, 주당 생산량 및 수량 효율은 재식밀도가 낮을수록 증가하는 경향이 있었고, 과중과 가용성고형물 함량은 목표 착과수준이 낮을수록 증가하는 경향이 있었다. 착색은 신초생장이 감소할수록 증가하는 경향이 있었다. 해거리는 238주과 260주 재식구의 주당 과실수가 각각 85-94과, 75-84과 이상이 되면 발생하였다. 그러나 190주 재식구는 주당 95-104과 정도 되어도 해거리가 발생하지 않았다. 누적 생산량은 재식밀도 및 목표 착과수준이 높을수록 많아지는 경향이 있었으나, 해거리가 발생한 착과구들 간의 차이는 없었다. 결론적으로 190주로 재식된 '후지'/M.9 사과나무의 성목기 적정 결실량은 95-104개, 238주 재식구는 75-84개, 260주 재식구는 65-74개 범위가 적당할 것이라고 판단되었다. This study was conducted in three years (7-9 years after planting) to investigate vegetative growth, yield, fruit quality, and return bloom for optimum crop load based on different planting densities of adult 'Fuji'/M.9 apple trees. As plant materials, 'Fuji'/M.9 apple trees planted at <TEX>$3.5{\times}1.5m$</TEX> (190 trees per 10 a), <TEX>$3.5{\times}1.2m$</TEX> (238 trees per 10 a), and <TEX>$3.2{\times}1.2m$</TEX> (260 trees per 10 a) spacing and trained as slender spindles were used. The crop load was assigned to five different object ranges as follows: 55-64, 65-74, 75-84, 85-94, and 95-104 fruit per tree. TCA increment, total shoot growth, return bloom, yield per tree, and yield efficiency tended to increase as planting density decreased, and fruit weight and soluble solid content tended to increase as the object range of crop load decreased. Fruit red color tended to increase as shoot growth decreased. For apple trees planted with 238 trees and 260 trees per 10a, biennial bearing occurred when the crop load was over 85-94 and 75-84 fruits, respectively. However, biennial bearing did not occur when the crop load was 95-104 fruits in apple trees planted with 190 trees per 10a. Accumulated yield tended to increase as planting density and crop load increased, but that of biennial bearing did not show such a difference. Based on our results, optimum crop load recommendations are to set 95-104 fruits per tree in 'Fuji'/M.9 mature apple trees planted at 190 trees per 10a, 75-84 fruits per tree at 238 trees per 10a, and 65-74 fruits per tree at 260 trees per 10a.

Effect of Integrated Nutrient Management on Growth, Yield and Quality of Gladiolus (Gladiolus grandifloru L.) Cv. Psittacinus Hybrid

American cranberry (Vaccinium macrocarpon) is naturally adapted to environments with high concentrations of soluble iron. Yet, there is a need to further explore iron nutrition in cranberry given concerns of toxicity problems from irrigation with iron-rich water. This study investigated the threat of iron toxicity by evaluating its effects on shoot growth total shoot weight, length (primary shoot and axillary growth), and number of axillary shoots in cranberry plants exposed to varying levels of a commonly used chelated iron, specifically Sequestrene 330 (ferric diethylenetriamine penta-acetate; Fe-DTPA). Cranberry plants were grown under controlled greenhouse conditions and received varying concentrations of Fe-DTPA in their irrigation water solutions. Four treatments of Fe-DTPA were applied (0, 14 ppm, 28 ppm, 56 ppm Fe), and shoot growth measurements were taken weekly over the course of 20 weeks. At the end of the course, total fresh shoot weight was recorded for each plant and tissues were sampled for nutrient analysis. Overall, shoot length (primary shoot and axillary) was significantly (P<0.05) reduced with increasing Fe-DTPA concentrations and plant symptoms included leaf drop, necrosis, and mortality in the higher concentration treatments. The number of axillary shoots per upright significantly (P<0.05) increased with treatment intensification. Nutrient analysis revealed increasing amounts of iron with increasing Fe-DTPA dosages. However, iron tissue levels were within the normal range found in healthy field plants (142.8-880.7 ppm) in all treatments. We hypothesized that the toxicity symptoms observed in cranberry plants treated with Fe-DTPA are likely not due to iron, but to a specific toxicity of cranberry to the chelators or other unknown components used in Fe-DTPA.

Planting Date and Staggered Seeding of Rye–Vetch Mixtures: Biomass, Nitrogen, and Legume Winter Survival

Mixtures of cereal rye (Secale cereale L.) and the legume hairy vetch (Vicia villosa Roth) are used to provide fixed N in balance with other important cover crop services, but late planting and interference from rye can limit vetch productivity. This 2‐yr study in Michigan investigated how fall planting dates influence rye–vetch cover crop biomass quantity and quality in the spring, and evaluated whether staggering (delaying) rye seeding could improve vetch performance (biomass production, N fixation, and winter survival) in mixtures. Treatments consisted of a two‐way factorial of three vetch planting dates (late August, mid‐September, and late September) and three lengths of rye seeding stagger (co‐seeded, short stagger, and long stagger). Later planting of co‐seeded mixtures generally led to reduced total shoot biomass and lower proportions of vetch, resulting in cover crop residues with less vetch N and a higher total C/N. For earlier planting dates, delaying rye seeding until vetch emergence (short stagger) increased vetch shoot biomass by 760 to 1060 kg ha−1 (30–36 kg vetch N ha−1) relative to co‐seeding. Staggered seeding provided no benefit to vetch biomass at later planting dates, and delaying rye seeding until the vetch three to four leaf stage (long stagger) reduced vetch winter survival by 12 to 42% compared with co‐seeding. Additional research is needed to determine whether potential on‐farm benefits of rye–vetch staggered seeding justify the additional management complexity involved and possible tradeoffs with other cover crop services.

Research Regarding the Influence of Plant Management System and Shoot Removal on the Intensity of Physiological Processes at Cucumber Cultivated in Solariums

Abstract The amount of light that reaches the leaves is essential in order to ensure a proper synthesis of organic matter at leaf level. When efficiently capitalizing the soil from protected areas, the plant management system for cucumbers cultivated in solariums have to be take into consideration, in respecti with the degree of self-shading and the amount of light received at the leaves level. The research highlight certain differences regarding the amount of light reaching the leaves and the intensity of certain physiological processes depending on the height up to which total shoot removal from the main stem was applied. Plant management system with total shoot removal at three levels of height (50 cm, 100 cm and 120 cm), showed that as much the part of the strain without shoots is lower, the self-shading degree is higher and the values of physiological parameters are lower.

Phloroglucinol Plays Role in Shoot Bud Induction and In Vitro Tuberization in Tinospora Cordifolia- A Medicinal Plant with Multi- Therapeutic Application

This paper shows the potential of phloroglucinol for In Vitro regeneration and tuberization of microshoots of Tinospora cordifolia. Within a week of nodal explants culture, axillary bud in nodal segments sprouted in all the media investigated including basal MS media without any growth regulators. Maximum response (52.2 per cent) evinced by MS media supplemented with 6.98 μM Kin. The same media produced maximum response for multiple shoot formation out of total shoot bud sprouted fostering average 3 shoots with 3.9 cm shoot length and 4.2 number of leaves per shoot. Effect of PG also investigated for mass multiplication and In Vitro rooting. Basal MS+6.98 μM Kin+79.4 μM PG increased shoot bud induction from 52.2 per cent to 84.8 per cent and multiple shoot production per cent from 12.9 to as high as 60.3 percent and also supported maximum number of shoot per explants (7.5). The same treatment promoted highest axillary shoot proliferation in terms of shoot length (3.9 cm) and number of leaves per shoot (4.3). Phloglucinol induced In Vitro tuberization in microshoots. Maximum rooting response observed in ½ MS medium supplemented with 7.4 μM IBA and 793.7 μM PG with 81.1 culture responding taking just 8.7 days to sprout and producing maximum number of roots (3.2) with an average length (3.1 cm). Rooted explants successfully hardened in Soil: Vermicompost: Vermiculite (1:1:1) with 100% success.