Dormant Shoots Research Articles

A structural variation in the promoter of the leucoanthocyanidin reductase gene AaLAR1 enhances freezing tolerance by modulating proanthocyanidin accumulation in kiwifruit (Actinidia arguta).

Proanthocyanidins (PAs) are importantmetabolites that enhance freezing tolerance of plants. Actinidia arguta, especially freezing-tolerant germplasms, accumulate abundant PAs in dormant shoots and thereby enhance freezing tolerance, but the underlying mechanism is unknown. In this study, we used two A. arguta with contrasting cold-resistant phenotypes,KL and RB, to explore the mechanisms in response to cold tolerance. We determined that a leucoanthocyanidin reductase gene (AaLAR1) was more highly expressed in freezing-tolerant KL than in freezing-sensitive RB. Moreover, overexpressing AaLAR1 in kiwifruit promoted PAs biosynthesis and enhanced cold tolerance. The AaLAR1 promoters of various A. arguta germplasms differ due to the presence of a 60-bp deletion in cold-tolerant genotypes that forms a functional binding site for MYC-type transcription factor. Yeast one-hybrid and two-hybrid, dual-luciferase reporter, bimolecular fluorescence complementationand coimmunoprecipitation assays indicated that the AaMYC2a binds to the MYC-core cis-element in the AaLAR1 promoter with the assistance of AaMYB5a, thereby promoting PAs accumulation in the shoots of cold-tolerant kiwifruit. We conclude that the variation in the AaLAR1 promoter and the AaMYC2a-AaMYB5a-AaLAR1 module shape freezing tolerance in A. arguta. The identification of a key structural variation in the AaLAR1 promoter offers a new target for resistance breeding of kiwifruit.

Reduced nitrogen fertilization from pre-flowering to pre-veraison alters phenolic profiles of Vitis vinifera L. Cv. Cabernet Gernischt wine of Yantai, China

Nitrogen (N) fertilization is important for grape growth and wine quality. Unreasonable N fertilizer application affects wine growth and has a negative impact on wine quality. Therefore, it is essential to address the mismatch between N application and wine composition. To regulate vine growth and improve grape and wine quality, Cabernet Gernischt (Vitis vinifera L.) grapevines were subjected to lower levels of N, compared to normal N supply treatments, during the grape growing seasons of 2019 and 2020 in the wine region of Yantai, China. The effects of reduced N application from pre-boom to pre-veraison on vine growth, yield and composition of grapes, and dry red wine anthocyanin and non-anthocyanin phenolic compound content were studied. We found that reduced N application significantly decreased dormant shoot fresh mass and yield. However, the effect of N application on fruit ripening depended on the season. Nitrogen-reduction treatment significantly improved wine phenolic parameters, including total phenolics, tannins, and anthocyanins, and enhanced most of the individual anthocyanins and some non-anthocyanin phenolics, especially stilbenes, including piceatannol, trans-resveratrol, and polydatin, regardless of the season. Overall, our findings highlight the importance of reducing N application during the grape growing season in order to modify the wine phenolic profiles.

Dynamics of GFLV, GFkV, GLRaV-1, and GLRaV -3 grapevine viruses transport toward developing tissues

AbstractViral diseases in grapevine cause large economic losses due to decreased irregular yield and unbalanced ripening, and can even lead to plant mortality. There is a large number of grapevine viral agents, and a few of them have a prominent impact due to their worldwide distribution, virulence, and incidence. Although previous research has evaluated variations in viral load between organs and time since infection, there is still a lack of knowledge on how the viruses are transported toward developing tissues. In this work, we present the results of two experiments that contribute to understanding the spread dynamics of four major grapevine viruses (GFLV, GFkV, GLRaV-1, and GLRaV -3). Bud and leaf tissues were sampled from shoots obtained from cv. ‘Garnacha’ cuttings known to be infected with one of these viruses. Bud samples taken at early development stages were used to understand short-distance transport, while leaves taken from young shoots represented long-distance transport, driven mainly through the phloem. Our results show that all viruses were able to invade tissues from the beginning of development. The dissemination ability of GFLV was considerable, as the viral load detected in young organs was as high as in the dormant shoot. Furthermore, for GFLV and GFkV, it was shown that the viral load in young shoots does not follow the general assumption of older tissues accumulating a higher viral load but, conversely, a higher viral load closer to the shoot tip might be driven by the sink strength.

In vitro Propagation of Curcuma caesia Roxb. via Bud Culture Technique and ISSR Profiling of the Plantlets for Genetic Homogeneity

An in vitro propagation protocol has been developed for Curcuma caesia Roxb., an endangered medicinal plant by Foundation for Revitalisation of Local Health Traditions and Central Forest Department of India. The plant bears poorly germinated seeds and produces two-storage organs: rhizomes and multiple root tubers. Only rhizomes have medicinal-economic values. They serve as propagules too, which results in a shortage of planting material. Therefore, a complete one-year production cycle of C. caesia has been standardized through in vitro propagation including explants establishment (one month), subculture cycles (seven months), rooting (one month) followed by primary hardening (one month) and secondary hardening (two months). Dormant shoot buds on rhizome served as explants for culture initiation on Murashige and Skoog (MS) medium supplemented with different concentrations of 6-benzyladenine (BA) and kinetin (KIN) in combination with citric acid (CA), adenine sulfate (AdS) and indole- 3-acetic acid (IAA). Maximum bud break (70%) was obtained on MS with 8 mg L-1 BA, 8 mg L-1 KIN, 100 mg L-1 CA, 200 mg L-1 AdS and 2 mg L-1 IAA (standard medium). Shoot production potential continued on this medium during the subsequent seven-month-long subculture cycle. The in vitro raised shoots rooted best on ½-strength MS containing 1 mg L-1 indole-3-butyric acid. Plantlet survival rate was >95% after acclimatization. The genetic homogeneity of plantlets with the mother plant was analyzed using Inter Simple Sequence Repeats which generated a monomorphic banding pattern to confirm the uniformity of in vitro raised plantlets of C. caesia.

Screening of cold hardiness-related indexes and establishment of a comprehensive evaluation method for grapevines (V. vinifera).

The goals of this work were to screen physiological and biochemical indexes to assess a set of V. vinifera germplasm resources, to compare evaluation methods for cold hardiness, and to establish a comprehensive method that can be used for more accurate screening for cold hardiness in V. vinifera. Four single methods were used to evaluate the cold hardiness of 20 germplasms resources and 18 physiological and biochemical indexes related to cold hardiness were determined. The LT50 values determined by electrical conductivity (EL), 2,3,5-triphenyltetrazolium chloride staining (TTC), differential thermal analysis (DTA), and recovery growth (RG) methods showed extremely significant positive correlation. Bound water content (BW), proline content (Pro), total soluble sugar content (TSS), malondialdehyde content (MDA), catalase content (CAT), and ascorbic acid content (ASA) exhibited significant correlation with LT50 values measured by different evaluation methods. The comprehensive cold hardiness index calculated by principal component analysis (PCA) combined with subordinate function (SF) was negatively correlated with LT50 values measured by different evaluation methods. Meili and Ecolly exhibited the highest cold hardiness, indicating their potential for use as parents for cold hardiness breeding. EL, DTA, TTC, and RG methods successfully distinguished cold hardiness among different V. vinifera germplasm lines. Measurements of BW, Pro, TSS, MDA, CAT, and ASA in dormant shoots also can be used as main physiological and biochemical indexes related to cold hardiness of V. vinifera. Comprehensive evaluation by PCA combined with SF can accurately screen cold hardiness in V. vinifera. This study provides a reference and accurate identification method for the selection of cold hardiness parents and the evaluation of cold hardiness of germplasm of V. vinifera.

Peltate trichomes in the dormant shoot apex of Metrodorea nigra, a Rutaceae species with rhythmic growth.

In Metrodorea nigra, a Rutaceae species with rhythmic growth, the shoot apex in the dormant stage is enclosed by modified stipules. The young organs are fully covered with peltate secretory trichomes, and these structures remain immersed in a hyaline exudate within a hood-shaped structure. Our study focused on the morpho-functional characterization of the peltate trichomes and cytological events associated with secretion. Shoot apices were collected during both dormant and active stages and processed for anatomical, cytochemical and ultrastructural studies. Trichomes initiate secretion early on, remain active throughout leaf development, but collapse as the leaves expand; at which time secretory cavities start differentiation in the mesophyll and secretion increases as the leaf reaches full expansion. The subcellular apparatus of the trichome head cells is consistent with hydrophilic and lipophilic secretion. Secretion involves two vesicle types: the smaller vesicles are PATAg-positive (periodic acid/thiocarbohydrazide/silver proteinate) for carbohydrates and the larger ones are PATAg-negative. In the first phase of secretory activity, the vesicles containing polysaccharides discharge their contents through exocytosis with the secretion accumulating beneath the cuticle, which detaches from the cell wall. Later, a massive discharge of lipophilic substances (lipids and terpenes/phenols) results in their accumulation between the wall and cuticle. Release of the secretions occurs throughout the cuticular microchannels. Continued protection of the leaves throughout shoot development is ensured by replacement of the collapsed secretory trichomes by oil-secreting cavities. Our findings provide new perspectives for understanding secretion regulation in shoot apices of woody species with rhythmic growth.

Genome-Wide Analysis of the Almond AP2/ERF Superfamily and Its Functional Prediction during Dormancy in Response to Freezing Stress.

Simple SummaryThe ethylene-responsive element (AP2/ERF) is one of the key and conserved transcription factors (TFs) in plants, and it plays a crucial role in regulating plant growth, development, and stress response. The cultivated almond in Xinjiang is often affected by short-term ultralow temperature freezing stress during the winter dormancy period, resulting in the death of large-scale almond plants. In this study, we conducted the first genome-wide analysis of the PdAP2/ERF family in almond, including protein physicochemical properties, phylogenetic relationships, motif types, gene structures, gene replication types, collinearity relationships, and cis-element types in promoter regions. We further analyzed the expression patterns of the PdAP2/ERF gene in different tissues of almond and under freezing stress at different temperatures in annual dormant branches using transcriptome data. In addition, we also analyzed the expression levels of 13 PdAP2/ERF genes in four tissues of almond and in annual dormant branches treated with freezing stress at different temperatures using fluorescence quantitative technology. This study laid the foundation for further exploring the function of the PdAP2/ERF gene in almond.The AP2/ERF transcription factor family is one of the largest transcription factor families in plants and plays an important role in regulating plant growth and development and the response to biotic and abiotic stresses. However, there is no report on the AP2/ERF gene family in almond (Prunus dulcis). In this study, a total of 136 PdAP2/ERF genes were identified from the almond genome, and their protein physicochemical properties were analyzed. The PdAP2/ERF members were divided into five subgroups: AP2, RAV, ERF, DREB, and Soloist. The PdAP2/ERF members in each subgroup had conserved motif types and exon/intron numbers. PdAP2/ERFS members are distributed on eight chromosomes, with 22 pairs of segmental duplications and 28 pairs of tandem duplications. We further explored the colinear relationship between almond and Arabidopsis thaliana, Oryza sativa, Malus domestica, and Prunus persica AP2/ERF genes and their evolution. The results of cis-acting elements showed that PdAP2/ERF members are widely involved in various processes, such as growth and development, hormone regulation, and stress response. The results based on transcriptome expression patterns showed that PdAP2/ERF genes had significant tissue-specific expression characteristics and were involved in the response of annual dormant branches of almond to low-temperature freezing stress. In addition, the fluorescence quantitative relative expression results of 13 representative PdAP2/ERF genes in four tissues of ‘Wanfeng’ almond and under six low-temperature freezing treatments of annual dormant branches were consistent with the transcriptome results. It is worth noting that the fluorescence quantitative expression level showed that the PdERF24 gene was extremely significant at −30 °C, suggesting that this gene may play an important role in the response of almond dormancy to ultralow temperature freezing stress. Finally, we identified 7424 and 6971 target genes based on AP2 and ERF/DREB DNA-binding sites, respectively. The GO and KEGG enrichment results showed that these target genes play important roles in protein function and multiple pathways. In summary, we conducted bioinformatics and expression pattern studies on PdAP2/ERF genes, including 13 PdAP2/ERF genes, and performed fluorescence quantitative analysis of annual dormant shoots under different low-temperature freezing stress treatments to understand the tolerance of almond dormancy to freezing stress and suggest future improvements.

Identification of novel genetic regions associated with resistance to European canker in apple

BackgroundEuropean canker, caused by the fungal pathogen Neonectria ditissima, is an economically damaging disease in apple producing regions of the world – especially in areas with moderate temperatures and high rainfall. The pathogen has a wide host range of hardwood perennial species, causing trunk cankers, dieback and branch lesions in its hosts. Although apple scion germplasm carrying partial resistance to the disease has been described, little is still known of the genetic basis for this quantitative resistance.ResultsResistance to Neonectria ditissima was studied in a multiparental population of apple scions using several phenotyping methods. The studied population consists of individuals from multiple families connected through a common pedigree. The degree of disease of each individual in the population was assessed in three experiments: artificial inoculations of detached dormant shoots, potted trees in a glasshouse and in a replicated field experiment. The genetic basis of the differences in disease was studied using a pedigree-based analysis (PBA). Three quantitative trait loci (QTL), on linkage groups (LG) 6, 8 and 10 were identified in more than one of the phenotyping strategies. An additional four QTL, on LG 2, 5, 15 and 16 were only identified in the field experiment. The QTL on LG2 and 16 were further validated in a biparental population. QTL effect sizes were small to moderate with 4.3 to 19% of variance explained by a single QTL. A subsequent analysis of QTL haplotypes revealed a dynamic response to this disease, in which the estimated effect of a haplotype varied over the field time-points.ConclusionsThis study describes the first identified QTL associated with resistance to N. ditissima in apple scion germplasm. The results from this study show that QTL present in germplasm commonly used in apple breeding have a low to medium effect on resistance to N. ditissima. Hence, multiple QTL will need to be considered to improve resistance through breeding.

Characterising retained dormant shoot attributes to support automated cane pruning onVitis viniferaL. cv. Sauvignon Blanc

Background and Aims The shortage of skilled pruners portends automation as an alternative. To train an Artificial Intelligence (AI) system in cane pruning, the attributes of grapevine dormant shoots were characterised. Methods and Results Eight attributes of dormant shoots, diameter, length, vertical and horizontal distance, node number, internode length, origin and position relative to bottom fruiting wire, were measured prior to and after pruning. Vine canopies were modified according to a 5 [total node numbers on canes: 10, 20, 30, 40, 50] × 3 [total node numbers on spurs: 1, 2, 3] factorial design. Compared to non-retained dormant shoots, retained dormant shoots were thicker (9.2 ± 0.07 mm), longer (104.7 ± 0.93 cm), close to the vine trunk (11.4 ± 0.65 cm) and below the bottom fruiting wire (83.2 ± 0.54 cm). Spurs had the shortest horizontal (9.8 ± 0.93 cm) and vertical (77.8 ± 0.7 cm) distance, originating from the vine head, base nodes and first nodes of old canes and old spurs. Modifying the vine canopy via increased node numbers had a significant effect on all retained dormant shoot attributes (P < 0.05) except on the position relative to the bottom fruiting wire. Conclusions Cane pruning in commercial vineyards is consistent and follows rules based on viticulture knowledge. Retained, non-retained dormant shoots, canes and spurs exhibit distinct attributes useful in quantifying, assessing and modelling cane pruning. Significance of the Study Data and knowledge from the research are currently being used in modelling and training AI cane-pruning algorithms.

Fertilization and pruning improve vegetative growth and architecture of tropical lowland Borneo Prima Mandarin citrus

Vegetative growth of citrus can be increased through a combination of fertilization and pruning. Borneo Prima Mandarin (Citrus reticulata cv Borneo Prima) is a superior local commodity that is grown in lowlands. It has an interesting orange skin, while normally the tropical lowland citrus has a green skin colour. As a new commodity, Borneo Prima Mandarin has to be developed in order to increase production and improve quality. There is no specific cultural practices, so it needs to be developed, especially on fertilizing and pruning. The first experiment aims to observe the plant growth and architecture of plants grown in the orchard. The first factor was the nitrogen fertilization rate (0, 20, 40, 60 g N per tree per application) and the second was pruning (without pruning, open center pruning, hedge pruning). In the second experiment, the plants were applied with the same factors of experiment 1, but were grown on a root observation chamber sized 40 x 20 x 60 cm (length x width x height) which aims to observe the shoot root’s growth and the plant’s biomass. Nitrogen fertilizer had a significant effect to the growth of the Borneo Prima Mandarin, i.e number of shoots and leaves. Twenty grams of nitrogen fertilizer per aplication was efficient to produce new shoots and leaves. Pruning treatments had significant effects towards the plant architecture (i.e reducing plant height, canopy shade projection and canopy length). Open center pruning and hedge pruning made the crown more open which increased the light interception. The shoot grew rapidly two weeks after fertilizing and also pruning. While the root grew rapidly after shoot dormancy.

Epicotyl morphophysiological dormancy in seeds of Paeonia ostii (Paeoniaceae): Seasonal temperature regulation of germination phenology

Paeonia is one of the most popular ornamental plants in temperate regions, and its seeds have epicotyl dormancy. Our primary aim was to determine the sequence of temperatures required for radicle and shoot emergence in seeds of P. ostii and how these two distinct stages of dormancy-break are correlated with natural seasonal temperature changes. We tested the effects of various temperature regimes and sequences of regimes on growth of the underdeveloped embryo inside the seed, radicle emergence and shoot growth in the laboratory and germination responses to temperature under natural temperatures in an experimental garden and analyzed ABA and GA concentrations during the dormancy-breaking process. Prior to radical emergence, embryo length increased c. 330%. Embryo elongation and radicle emergence occurred in early October following seed dispersal in summer. The epicotyl-plumule did not differentiate until after embryo growth was completed and the radicle had emerged. Cold stratification was required to break epicotyl dormancy; consequently, shoot emergence did not occur until February when the temperature began to increase. Thus, seed dormancy break in P. ostii is phenologically well adapted to the seasonal cycle of the temperate zone. ABA and GA analyses suggest that root dormancy might be due to high ABA content and shoot dormancy to low GA content. • Seeds of Paeonia ostii have deep simple epicotyl morphophysiological dormancy. • The plumule does not differentiate until embryo growth is competed. • Radicle emergence occurs only at warm temperatures in autumn. • Shoots emerge only in spring in root-emerged seeds that have been cold stratified. • The timing of dormancy-break is regulated by changes in seasonal temperatures.

Utilization of bio-organo mineral as a soil ameliorant for hard crops

The research objective was to make a formula for economical complex soil conditioner of bio-organo mineral for tea, coffee and cacao plantations. The soil conditioner (SC) formula for such plantations was made by mixing the urea, phosphate, leucite and kieserite with the ratio of 25:7:12:3. The experiments at Block B5 showed the amount of harvested dormant leaves was 3.37 kg/100 m2 while the control yielded 2.29 kg/100 m2. There is a difference around 1.08 kg/100 m2 or 47%. The amount of Peko shoots was 19.82 g/100 m2 when using the soil conditioner while the control had 14.89 g/100 m2 performing the difference 33% while at Block A10, the amount of harvested dormant shoot was 3.53 kg/100 m2. There is a difference around 3.29 kg/100m2 or 7%. The amount of Peko shoot was 18.25 g/100 m2 while the control acquiesced 15,05 g/100m2 – the difference of both was 21%. The Robusta grew from 25.4 cm to 28.5 cm when using the BIOM-SC. but the plant height is only from 24.4 cm to 26.8 when using NPK fertilizer.

Gibberellins, brassinolide, and ethylene signaling were involved in flower differentiation and development in Nelumbo nucifera

Hormones play important roles in vegetative and reproductive processes; however, the regulatory roles of hormones in Nelumbo nucifera (Lotus) growth and development are unclear. In this study, nine types of endogenous hormones, including gibberellins (GA1, GA3, and GA4), indole-3-acetic acid (IAA), brassinolide (BR), ethylene (ETH), jasmonic acid (JA), abscisic acid (ABA), and zeatin (ZT) were detected in dormant shoot tips, vegetative shoot tips, developing leaf buds, and developing flower buds of lotus. The results indicated that GA, ETH, and BR signaling can promote vegetative and reproductive development of lotus. GA signaling regulates plant height and stimulates flower bud differentiation. GA levels were the highest in the flower buds; exogenous GA3+4 increased plant height by approximately 90%, increased flower quantity by nearly 40%, and advanced flowering by 4 d. Suppressing GA biosynthesis using paclobutrazol decreased plant height and flower quantity by 38% and 87.1%, respectively, and delayed flowering by 15.6 d. ETH signaling has positive regulatory effects on vegetative growth and flower development. The ETH concentration in the developing leaf buds was at least 50% higher than that in other samples. Ethephon spraying led to remarkable increases in plant height and leaf thickness and extended the flowering duration. BR signaling acts as a growth promoter during vegetative and reproductive development in lotus. The highest BR levels were detected in the vegetative shoot tips. External application of 28-epihomobrassinolide resulted in growth-promoting phenotypes including longer scapes, thicker leaves, and prolonged flowering.

Germination ecology of Trachycarpus fortunei (Arecaceae), a species with morphophysiological and shoot dormancy

Beyond strong inference that most of the 2600 known species of Arecaceae produce diaspores with an underdeveloped embryo and therefore have morphological dormancy (MD) or morphophysiological dormancy (MPD), little is known about the specific dormancy class or sub-class and how dormancy-break occurs under ecological conditions. Here, we found that mature seeds of Trachycarpus fortunei (Hook.) H.Wendl. collected at the time of natural dispersal had an underdeveloped embryo that was 10% of total seed length. No diaspores germinated over a wide range of temperatures in either light or darkness. Cold stratification at 4 °C for one, two, and three months or treatment with 100, 500, and 1000 ppm gibberellic acid (GA3) improved germination percentages, with three months cold stratification or 1000 ppm GA3 resulting in highest germination. The embryo grew inside the seeds during cold stratification; however, warm stratification did not improve germination. Therefore, seeds of T. fortunei have intermediate complex MPD. Cold-stratified seeds that were moved to spring conditions (night and day temperatures of 15 and 20 °C, respectively) had cotyledonary petiole (CP) elongated, but leaves developed only when the CP elongated seeds were moved to summer temperatures (night and day temperatures of 25 and 30 °C, respectively), suggesting the presence of shoot dormancy. The seedlings are remote-tubular type. This is the first report for Arecaceae indicating the presence of complex MPD.

Morphological Characteristics and Transcriptome Comparisons of the Shoot Buds from Flowering and Non-Flowering Pleioblastus pygmaeus

Bamboo plants have a distinctive life cycle with long flowering periodicity. Many species remain in vegetative growth for decades, followed by large-scale flowering and subsequent death. Floral transition is activated while shoot buds are still dormant in bamboo plants. In this study, we performed morphological characterization and transcriptome analysis of the shoot buds at different growth stages from flowering and non-flowering Pleioblastus pygmaeus. The morphological and anatomical structures of the dormant shoot buds were similar in flowering and non-flowering plants, while there was an obvious difference between the flower buds from flowering plants and the leaf buds from non-flowering plants. The transcriptomes of the dormant shoot buds, germinated shoots, and flower buds from flowering P. pygmaeus, and the dormant shoot buds, germinated shoots, and leaf buds from non-flowering P. pygmaeus were profiled and compared by RNA-Seq. The identified sequences were mostly related to metabolic synthesis, signal transmission, translation, and other functions. A total of 2434 unigenes involved in different flowering pathways were screened from transcriptome comparisons. The differentially expressed unigenes associated with the photoperiod pathway were related to circadian rhythm and plant hormone signal transduction. Moreover, the relative expression levels of a few key flowering-related genes such as CO, FT, FLC, and SOC1 were quantified by qRT-PCR, which was in accordance with RNA-Seq. The study revealed morphological differences in the shoot buds at different growth stages and screened flowering-related genes by transcriptome comparisons of the shoot buds from flowering and non-flowering P. pygmaeus, which will enrich the research on reproductive biology of bamboo plants and shed light on the molecular mechanism of the floral transition in bamboo plants.

The Effect of Pyraclostrobin Application on Yield of Tea (Camelia sinensis (L.) O. Kuntze) under Wet Season

This field experiment aimed to study the effect of pyraclostrobin on tea production and to determine optimum concentration in order to maintain high yield during the period of wet season. The experiment was arranged in Randomized Completely Block Design (RCBD) using single factor and three blocks as replications. The pyraclostrobin doses, consisted of 4 levels, 0, 50, 100, and 150 g.ha-1, each will be tested on three tea clones. Clones tea tested are TRI 2025, Gambung 9 and PGL 15. Data was evaluated for chlorophyll content, photosynthetic rate, number of pecco, number of dormant shoot (banjhi), number of total shoot, pecco fresh weight, banjhi fresh weight, total shoot fresh weight, and shoot dry weight. Data were analysed by using Analysis of Variance (ANOVA) and LSD test at α = 5%. The results informed that pyraclostrobin was able to improve chlorophyll content on TRI 2025 clone, and improved photosynthetic rate on Gambung 9 clone. However, there was no significant different among plants treated with pyraclostrobin on a yield components, i.e., number of pecco, number of banjhi, pecco fresh weight, banjhi fresh weight, total shoot fresh weight, and total shoot dry weight.

Overcoming root dormancy and identifying the storage behaviour of Lilium polyphyllum seeds

Lilium polyphyllum D.Don ex Royle is a critically endangered medicinal herb of Himalaya. Seeds have epicotyl morphophysiological dormancy, and in the field a minimum of 34 weeks is required for root emergence. To date, treatments to decrease the time for root protrusion and seed storage behaviour have not been determined. We evaluated the effects of plant growth regulators and nitrogenous compounds as well as seed scarification on root emergence, and determined the storage behaviour of seeds. Root emergence at 20 °C was significantly increased by 100 ppm of indole butyric acid (IBA), KNO3, and thiourea, and by the application of NaOCl solution for 30 min. The mean germination time was significantly decreased by 50 ppm of gibberellic acid (GA3; 28 days) compared with 100 ppm GA3 (36 days). After 12 months of dry storage, the viability of seeds (TTC method) at room temperature (10–35 °C), 0–4 °C, and −20 ± 1 °C was 95%, 100%, and 100%, respectively; thus, the seeds have orthodox storage behaviour. Our recommendation for seedling production is to store the seeds at room temperature until they can be sown under warm wet conditions. Roots emerge after about 8 weeks, and then seeds should be given a 2-week cold moist treatment to break shoot dormancy. After 2 weeks of cold, transfer the seeds to warm (20 °C) spring temperature conditions to promote growth.

English

Due to its fast growth rates, Moringa oleifera is being grown as an annual crop in temperate areas with freezing winter temperatures. Seedlings are raised under greenhouse conditions for overwintering and then transplanted outside at the beginning of spring, which allows for several cuttings prior to onset of the subsequent winter. However, there is limited information on container-size for overwintering of M. oleifera seedlings under greenhouse conditions. The objective of this study was to determine the responses of M. oleifera root growth to different container-sizes during overwintering in temperate regions under greenhouse conditions. Uniform two-month old seedlings were hardened-off and transplanted into five different container-sizes, measured in volume. Seedlings were fertilised once at transplanting and irrigated through scheduling with moisture meter. Six months after the treatment, container-size had highly significant effects on root length and crown girth, contributing 91 and 60% to total treatment variation of the respective plant variables. Root length and container-size exhibited quadratic relations, with optimum container-size computed to be 300 ml. In contrast, crown girth and container-size exhibited linear relations. In conclusion, the findings in this study suggested that a much smaller container (300 ml) than the one currently used (750 ml) would allow optimum overwintering of M. oleifera seedlings, thereby reducing production costs. Key words: Container-cost, crown girth, labour-cost, Moringa species, shoot dormancy, root development.

Plant oils as oviposition deterrents against winterform females of pear psylla, Cacopsylla pyri (L.) (Hemiptera: Psyllidae)

Oviposition deterrents have potential to prevent arthropod pest infestations making the crop habitat less or no favorable for pests to lay eggs and even to settle. In this study, seed oils of maize, safflower, rapeseed and castor oil plant were evaluated in the field between years of 2015 and 2016 for their oviposition deterrent activity against winterform females of pear psylla, Cacopsylla pyri (L.) (Hemiptera: Psyllidae), the most important insect pest of pears in Turkey. All the oils were used at three different concentrations, 1, 1.5 and 2 L/100 L water including 0.01% Tween-20 for a good mixture and applied at the dormant period (just before the first eggs were deposited by overwintered females). Only one application was made each year. Oviposition deterrency was evaluated by counts of eggs deposited by overwintered females of the pest on treated dormant shoots during the sampling times 3, 7, 14, 21 and 28 days after application. The results showed that significant reductions in total numbers of eggs laid by winterform females were observed in all the oil-treated plots compared with the controls sprayed with tap water including Tween-20 (0.01%). Safflower and castor oils exhibited 100% oviposition deterrent activity at all the concentrations during the 3 weeks period in both years. Even after 4 weeks, the deterrency of these oils was higher than 70%. In the control plots, the first eggs were deposited by overwintered females within 3 days after application in both years. These findings suggest that these oils are promising oviposition deterrents against winterform females of C. pyri.

Responses of Young 'Fuyu' Persimmon Trees to Summer Fertilization Rate and Leaf-fruit Ratio

Small-sized persimmons produced by high crop load are better accepted in the export markets. However, maintaining high crop load frequently results in weakness of tree vigor, deterioration of fruit quality, and increase of the risks for alternate bearing. This experiment was conducted to determine the combined effects of fertilization rate and leaf-fruit (L/F) ratio on container-grown 3-year-old ‘Fuyu’ persimmon trees. Application of 3.6-g N, 2.1-g P₂O 5 , 2.7-g K₂O, 2.7-g CaO, and 0.6-g MgO was for the control fertilization rate (CF) and that of a 3-fold CF was for the high fertilization rate (HF). Commercial fertilizers were surface-applied to a container on July 6, July 17, and August 10 in three equal aliquots. Single tree for each fertilization rate was assigned for 12 L/F ratios (5, 6.3, 7.7, 9, 10.4, 13, 15.5, 18, 21, 24, 27, and 33) mostly by fruit thinning or rarely by defoliation on July 1. HF did not affect the yield, weight and soluble solids of the fruits but decreased skin color. As L/F ratio increased, yield decreased but average weight, skin color, and soluble solids of fruits increased. With HF, N and K concentrations in leaves, fruits, and shoots increased to some extent but soluble sugars in dormant shoots decreased. Many shoots were cold-injured with low L/F ratio especially at the HF. HF did not increase number of flower buds the next spring either on a shoot or on a tree basis but increased shoot length, compared with the CF. Increasing L/F ratio markedly increased number of flower buds and shoot growth the following year at both fertilization rates. Therefore, an appropriate combination of fertilization rate and L/F ratio should be necessary to maintain stable fruit production and tree vigor at high crop load.