Allelopathic effect of ginger on seed germination and seedling growth of soybean and chive

The rhizome, stem and leaf aqueous extracts of ginger were assayed at 10, 20, 40, and 80 g l⁻¹ for their effects on seed germination and early seedling growth of soybean and chive. All aqueous extracts at all concentrations inhibited seed germination, seedling growth, water uptake and lipase activity of soybean and chive compared with the control, and the degree of inhibition increased with the incremental extracts concentration. The degree of toxicity of different ginger plant parts can be classified in order of decreasing inhibition as stem > leaf > rhizome. The results of this study suggest that rhizome, stem and leaf of ginger contain water-soluble allelochemicals which could inhibit seed germination and seedling growth of soybean and chive. The rhizome is the main harvested part of ginger. The residue (mainly stems and leaves) of the ginger plant should be removed from the field so as to diminish its inhibitory effect. Further work is needed to specify and verify the allelochemicals produced by this plant. The results of this study suggest that ginger allelochemicals are heterotoxic, and thus intercropping should not be practiced using ginger.     

Variation in total phenolics and antioxidant capacity among European plum genotypes

Our objective was to determine the amount of variation in total phenolics and antioxidants present in European plum fruits, so that it can be utilized in breeding programs to enhance the health benefits. Total antioxidant capacity and total phenolic content of the fruit, and the fruit skin color were determined in 20 genotypes, comprising of released varieties and advanced selections of European plums. Among the 20 genotypes, the total antioxidant capacity ranged from 105 to 424 mg ascorbic acid equivalents (AAE)/100 g fresh weight (FW) while the total phenolic content was 86–413 mg gallic acid equivalents (GAE)/100 g FW. The two parameters had a strong correlation of r² = 0.96. A direct correlation between skin color intensity and total phenolic content could also be observed. This study demonstrates that there is adequate variation in total phenolic compounds and antioxidants within European plums and hence there is potential for improvement towards enhancing these health-promoting phytochemicals in this fruit.     

Screening and selecting novel AM fungi and Azotobacter strain for inoculating apple under soil solarization and chemical disinfestation with mulch practices for sustainable nursery management

The objective of this study is to investigate the response of screening, and selection of novel indigenous AM fungal species and Azotobacter chroococcum strains for inoculating apple under different soil disinfestations and moisture conservation mulch practices for sustainable nursery management. Two local AM fungal species namely, Glomus fasciculatum (Thaxter sensu Gerdemann) and Glomus mosseae (Nicol. & Gerd.), and two strains of A. chroococcum viz., A. chroococcum strain-I (AZ₁) and A. chroococcum strain-II (AZ₂) were inoculated at nursery stage under soil solarization, chemical disinfestation and natural soil conditions at four different mulch materials namely, black plastic mulch (BPM), and organic mulches, i.e. grass mulch (GM); cover crops (CC); green manuring + clean cultivation (Gm + Cc). The comparative performance of the seedlings on the impact of local AM species and A. chroococcum strains on growth characteristics, microbial population, root colonization and leaf nutrient status was evaluated. The inoculation of seedlings to G. fasciculatum and AZ₁ increased all growth characteristics (plant height, stem diameter, leaf area and total root length), microbial consortium of the rhizosphere soil and leaf N, P, K and Zn content in all those plots where soil solarization and black plastic mulching was used followed by chemical disinfestations and natural soil conditions at all other mulch types used. These findings suggested that the soil inoculation of G. fasciculatum and AZ₁ strain to seeds and/or the saplings under soil solarization with black plastic mulch attained a desirable plant height and become ready for grafting which however saved a period of 1 year for nursery management compared to traditional nursery raising practice, and thus, it may be a viable and feasible approach to maintain soil productivity under nutrient limited soils for sustainable apple nursery production under temperate rain-fed conditions.     

Correlations between quantitative tree and fruit almond traits and their implications for breeding

Correlations between 29 quantitative tree and fruit traits were studied in 46 almond genotypes and some inter-specific crosses. Results reflected a significant diversity in the assayed almond germplasm. In addition, the obtained cluster demonstrated varying degrees of relationships, illustrating higher correlation values for the flowering traits and lower correlation values for the nut and kernel traits. To determine the importance of the traits and the levels of similarity existing between the various studied traits, a discriminate analysis was carried out. According to the results obtained from these analyses, the different traits were discriminated on basis of the characteristics of the presence of double kernels, the nut and the kernel size, the flowering date, kernel yield and shelling percentage. Finally, this study evidenced correlations between most of the agronomic traits in almond, although the correlations coefficient (r) value was found to be higher than 0.5 only in some cases. This analysis can help breeders for choosing the most favorable entries to build a core subset of the almond collection for the purpose of breeding.     

Modeling plant morphology and development of petunia in response to temperature and photosynthetic daily light integral

The effects of mean daily temperature (MDT) and mean photosynthetic daily light integral (MDLI) on flowering during the finish stage of two petunia (Petunia × hybrida) cultivars were quantified. Petunia ‘Easy Wave Coral Reef’ and ‘Wave Purple’ were grown in glass-glazed greenhouses at 14–23 °C or 14–26 °C and under 4–19 mol m⁻² d⁻¹ with a 16-h photoperiod. The flower developmental rate was predicted using a model that included a linear MDT function with a base temperature multiplied by an exponential MDLI saturation function. The flower developmental rate increased and time to flower decreased as MDT increased within the temperature range studied. For example, under a MDLI of 12 mol m⁻² d⁻¹, as MDT increased from 14 to 23 °C, time to flower of ‘Easy Wave Coral Reef’ and ‘Wave Purple’ decreased from 51 to 22 d and 62 to 30 d, respectively. Flower developmental rate increased as MDLI increased until saturation at 14.1–14.4 mol m⁻² d⁻¹. Nonlinear models were generated for effects of MDT and MDLI on flower bud number and plant height at flowering. The number of flower buds at flowering increased as MDT decreased and MDLI increased. For example, at an MDT of 14 °C with 18 mol m⁻² d⁻¹, plants had 2.5–2.9 times more flower buds than those grown at 23 °C and 4 mol m⁻² d⁻¹. Models were validated with an independent data set, and the predicted time to flower, flower bud number, and plant height were within ±7 d, ±20 flowers, and ±4 cm, respectively, for 96–100%, 62–87%, and 93–100% of the observations, respectively. The models could be used during greenhouse crop production to improve scheduling and predict plant quality of these petunia cultivars.     

Zinc influence and salt stress on photosynthesis,water relations,and carbonic anhydrase activity in pistachio

A greenhouse study was conducted to evaluate the ameliorative effects of zinc (0, 5, 10 and 20 mg Zn kg⁻¹ soil) under saline (800, 1600, 2400 and 3200 mg NaCl kg⁻¹ soil) conditions on pistachio (Pistacia vera L. cv. Badami) seedlings’ photosynthetic parameters, carbonic anhydrase activity, protein and chlorophyll contents, and water relations. Zn deficiency resulted in a reduction of net photosynthetic rate and stomatal conductance. The quantum yield of photosystem II was reduced at zinc deficiency and salt stress. Zinc improved plant growth under salt-affected soil conditions. Increasing salinity in soil under Zn-deficient conditions, generally decreased carbonic anhydrase activity, protein, chlorophyll a and b contents. However, these adverse effects of salinity alleviated by increasing Zn levels up to 10 mg kg⁻¹ soil. Under increasing salinity, chlorophyll a/b ratio significantly increased. Zinc treatment influenced the relationship between relative water content and stomatal conductance, and between leaf water potential and stomatal conductance. It concluded that Zn may act as a scavenger of ROS for mitigating the injury on biomembranes under salt stress. Adequate Zn also prevents uptake and accumulation of Na in shoot, by increasing membrane integrity of root cells.     

Characterization of plant material obtained by in vitro androgenesis and in situ parthenogenesis in apple

The production of doubled haploids offers new possibilities for genetic studies and breeding. In apple Malus × domestica Borkh., double haploid and thus homozygous material was obtained by in vitro androgenesis and in situ parthenogenesis followed by embryo or cotyledon culture. This paper describes a comprehensive evaluation of material induced concerning ploidy level, zygosity state using isozyme and SSR analysis, tree morphology, flower, and fruit quality, respectively. The use of homozygous lines in apple will be discussed in view of the efficiency of the induction process and the fertility of the plant material. The application in running breeding programmes is not a realistic approach at present, while single lines with selected characteristics can already be used for pre-breeding experiments and detailed genetic studies.     

Quantitative trait analysis of transplanting time and other root-growth-related traits in tomato

Transplanting time is determined by factors such as the field conditions, the age of the seedlings, and the size of the container, but little information is available on the effect of the genetic background on transplanting time. Here, we examined root dry weight (RDW), shoot dry weight, root/shoot ratio (RSR), time at which 50% of the germinated seedlings have expanded cotyledons (CE50), root ball formation (RBW), the length of time from the cotyledon expansion from the first to the last germinated seedling (ES) and transplanting time (TRD) in a BC₁F₆ population derived from Solanum lycopersicum and Solanum pimpinellifolium. All traits exhibited significant correlation with each other, except for RSR, which was only significantly correlated to RDW. A total of eight additive quantitative trait loci (QTLs) were detected for the five traits, i.e., RSR, RBW, CE50, ES, and TRD. One epistatic (QTL × QTL) interaction each was identified for RSR and TRD. QTLs for RSR, RBW, CE50, ES and TRD clustered near marker LEOH37 on chromosome 4. Clustering of ce50-4, rsr4, rbw4, and es4 with trd4 reflected the dependence of transplanting time on root ball formation, growth uniformity and early seedling growth, especially root growth. In addition, several QTLs in this study were mapped to regions where QTLs for days to flowering or number of leaves before the first inflorescence had been identified previously. This suggests that the roots may exert some influence on the flowering time in tomato.     

Asymbiotic seed germination,mass propagation and seedling development of Vanda coerulea Griff ex.Lindl. (Blue Vanda): An in vitro protocol for an endangered orchid

The application of modern biotechnology for conservation of any endangered species requires an efficient in vitro regeneration protocol. In this study a reliable protocol was developed for in vitro seed germination, protocorm multiplication and subsequent plantlet regeneration of Vanda coerulea, an endangered orchid species. Among the four basal media evaluated for asymbiotic seed germination, Phytamax was found to be the best followed by Murashige and Skoog (MS). Phytamax was also found good for protocorm development. For protocorm like body (PLB) regeneration, protocorms were then further cultured on Phytamax media fortified with different phytohormones either individually or in combinations. The frequency of protocorm like body (PLB) regeneration significantly relied on kinds and concentrations of plant growth regulators used. A combination of 1-naphthaleneacetic acid (NAA) (5.36 μM) and 6-benzyle amino purine (BAP) (3.80 μM) was found to be suitable for maximum PLB regeneration. Healthy plantlets were induced from PLBs when cultured on same basal medium supplemented with activated charcoal (AC – 3.0 g/l). Plantlets with well developed leaves and roots were transplanted to pots filled with a mixture of charcoal, brick pieces and sphagnum moss and transferred to the greenhouse. This protocol will enable mass propagation and conservation of this exquisite orchid.     

Evidence for a translocatable florigenic promoter in mango

Movement of a putative florigenic promoter from leaves to buds was investigated in two cultivars of mango (Mangifera indica L.) over two flowering seasons through examination of the minimum number of leaves on each stem necessary for floral induction and movement of this component over various distances from stem to stem in isolated branches. The minimum number of leaves on individual stems necessary to induce flowering was less than 1/4 of a cross-cut leaf per stem. The putative florigenic promoter moved from donor stems bearing as few as one leaf to induce flowering in five receiver stems located as far down branches as 100 cm from the donor stem. Evidence suggests that movement of the putative florigenic promoter occurs in phloem and that far more of this component is available in trees than is necessary for floral induction of initiating shoots during cool, floral-inductive conditions of the subtropics.     

EST-PCR markers developed for highbush blueberry are also useful for genetic fingerprinting and relationship studies in rabbiteye blueberry

The pedigrees of most rabbiteye blueberry (Vaccinium virgatum) cultivars can be traced back to four wild selections, ‘Ethel’, ‘Clara’, ‘Myers’, and ‘Black Giant’; thus, they result from a very narrow germplasm base and are highly related. Until now randomly amplified polymorphic DNA (RAPD) has been the only type of molecular marker used in rabbiteye blueberry. Here we have tested whether a type of sequence-tagged site (STS) marker which utilizes specific ∼20-mer primers from expressed sequence tags (ESTs) of highbush blueberry (V. corymbosum), called EST-PCR markers, are useful for genetic fingerprinting and relationship studies in rabbiteye blueberry. Of 44 EST-PCR primer pairs, from an assortment of genes expressed in flower buds of cold acclimated and non-acclimated plants, and shown to amplify polymorphic fragments among a collection of highbush genotypes, 40 (91%) resulted in successful amplification, and 33 of those (83%) amplified polymorphic fragments among the rabbiteye genotypes. The average number of scorable bands per primer pair was two. A dendrogram constructed from genetic similarity values, based on the EST-PCR marker data, tended to group siblings and parent/progeny together, generally agreeing with pedigree information. A group of 20 markers from five EST-PCR primer pairs distinguished all the genotypes in this study. These markers are as easy to generate and as affordable as RAPDs, but are based on actual gene sequences, and should have general utility for DNA fingerprinting, genetic diversity, and mapping studies.     

S-RNase based S-genotyping of Japanese plum (Prunus salicina Lindl.) and its implication on the assortment of cultivar-couples in the orchard

Determination of the genetic compatibility between self-incompatible cultivars is crucial in agriculture. The Rosaceae family carries the S-RNase-mediated gametophytic self-incompatibility (GSI) system. Each haplotype is conferred by an S-locus. The S-locus contains two highly polymorphic genes, S-RNase and SFB, which are characteristic of each haplotype and therefore these genes are ideal markers for molecular S-genotyping. In this study 43 Japanese plum cultivars grown in Israel were S-genotyped based on their S-RNase gene sequences. Four alleles, S^b, S^c, S^e and S^h are widespread and together are responsible for 87% of the S-haplotypes therefore many of the cultivar combinations are semi-compatible. In Israel semi-compatibility was shown to correlate with low yield. However, two cultivars, ‘Wickson’ S^fS^k and ‘Shiro’ S^fS^g carry rare S-haplotypes and, therefore, are fully compatible with most of the analyzed cultivars.     

Transpiration,photosynthetic responses,tissue water relations and dry mass partitioning in Callistemon plants during drought conditions

Callistemon is an Australian species used as ornamental plant in Mediterranean regions. The objective of this research was to analyse the ability of Callistemon to overcome water deficit in terms of adjusting its physiology and morphology. Potted Callistemon laevis Anon plants were grown in controlled environment and subjected to drought stress by reducing irrigation water by 40% compared to the control (irrigated to container capacity). The drought stress produced the smallest plants throughout the experiment. After three months of drought, the leaf area, number of leaves and root volume decreased, while root/shoot ratio and root density increased. The higher root hydraulic resistance in stressed plants caused decreases in leaf and stem water potentials resulting in lower stomatal conductance and indicating that water flow through the roots is a factor that strongly influences shoot water relations. The water stress affected transpiration (63% reduction compared with the control). The consistent decrease in g_s suggested an adaptative efficient stomatal control of transpiration by this species, resulting in a higher intrinsic water use efficiency (P_n/g_s) in drought conditions, increasing as the experimental time progressed. This was accompanied by an improvement in water use efficiency of production to maintain the leaf water status. In addition, water stress induced an active osmotic adjustment and led to decreases in leaf tissue elasticity in order to maintain turgor. Therefore, the water deficit produced changes in plant water relations, gas exchange and growth in an adaptation process which could promote the faster establishment of this species in gardens or landscaping projects in Mediterranean conditions.     

Dry weight and carbohydrate distribution in different tree parts as affected by various fruit-loads of young persimmon and their effect on new growth in the next season

This study was conducted to determine the changes in the accumulation of dry weight (DW) and the distribution of carbohydrates in different parts of young persimmon (Diospyros kaki) as affected by various fruit-loads. The effects of such changes were monitored with regard to the abundance of new growth in the following year. On June 15, the fruit-load was adjusted to a leaf–fruit (L/F) ratio of 10, 20, and 30, and some trees were completely defruited. Between June 15 and November 11, the increase in DW was less in the defruited and more in the higher L/F-ratio trees. Among the various tree parts, the DW increased the most in the fruits during the same period. It was observed that the lower the L/F ratio, the more the DW in the fruits: the fruits accounted for 78.7% of the total DW in the 10-L/F, 57.6% in the 20-L/F, and 49.7% in the 30-L/F ratio trees. In contrast, as the L/F ratio increased, the DW distribution to the roots increased to 3% in the 10-L/F, 13% in the 20-L/F, and 26% in the 30-L/F ratio trees and 61% in the defruited trees. During this period, carbohydrates were distributed mostly to the fruits, but as the L/F ratio decreased, their distribution to permanent tree parts decreased. The distribution of soluble sugars and starch to the permanent parts was 1% and 14% in the 10-L/F, 3% and 48% in the 20-L/F, 9% and 57% in the 30-L/F ratio trees, and 71% and 93% in the defruited trees, respectively. Maintaining a lower L/F ratio resulted in a decrease in the shoot and fruit numbers in the following year: there were zero and four fruits in those trees with an L/F ratio of 10 and 20, respectively. The carbohydrates decreased in the roots of both the 30-L/F ratio trees and the defruited trees, whereas the defruited trees showed more new shoot growth in the following year. In the roots of the trees with the L/F ratio of 30, soluble sugars and starch decreased by 7.6 g and 1.8 g, respectively, during the spring growth, whereas, in the roots of the defruited trees soluble sugars and starch decreased by 33.3 g and 94.6 g, respectively.     

Nutrient deficiency disorders in Pistacia vera seedling rootstock in relation to eco-physiological,biochemical characteristics and uptake pattern of nutrients

This study examines the effects of nitrogen (N), iron (Fe), magnesium (Mg), manganese (Mn) and molybdenum (Mo) deficiencies on the eco-physiological, biochemical and growth characteristics of pistachio seedlings (Pistacia vera) in sand culture situation. This experiment, which was carried out in Iran's Pistachio Research Institute (IPRI), seedlings of ‘Badami-e-Zarand’ were used as common rootstock. The following treatments were employed: (1) complete Hoagland's nutrient solution; nutrient solution lacking either: (2) N, (3) Fe, (4) Mg, (5) Mn, (6) Mo, (7) distilled water without Hoagland's solution (Control), (8) Fe–N, (9) Fe–Mn and (10) Fe–Mo. The main deficiency symptoms observed after 7 months of planting were; leaf discoloration, necrosis, scorching, defoliation and stunted growth. Seedlings that received complete nutrient solution were healthy with dark green foliage. Visual symptoms of N-deficient seedlings also coincided with the reduction in foliar levels of the concerned element. Shoot and root growth of the seedlings deficient in nutrients were also affected. Changes in shoot and root biomasses production due to treatments were statistically significant at 1% level. A reduction in height, leaf area and leaf number was noticed for various levels of nutrient element deficiencies. Analysis of some biochemical indices (chlorophyll content) and eco-physiological indices such as primary florescence chlorophyll (Fo), ratio of variable chlorophyll to maximum (Fv/Fm), leaf temperature, transpiration, stomata conduction and resistance of stomata, showed that fractions of chlorophyll, transpiration, stomata conduction and resistant of stomata in treated seedlings, particularly N-deficient seedlings, declined significantly. Chlorophyll (Fo) and ratio of variable chlorophyll to maximum (Fv/Fm) were significant at 5% level. The effects of Fe, Mn, Mg and Mo on dry matter production were statistically significant at 1% level. Synergic effects of certain elements were also evident in the present study. The typical symptoms of deficiencies of various nutrient elements can be used as a guideline for diagnosing nutrient deficiencies of pistachio in commercial nurseries and plantations. The present study also showed multi-deficiency of nutrients, produces new symptom in leaves, which differs from single deficiencies.     

Cucumber fruit quality at harvest affected by soilless system,crop age and preharvest climatic conditions during two consecutive seasons

Cucumber fruits (Cucumis sativus L., cv. Trópico F1) grown on perlite substrate and NFT (Nutrient Film Technique) were harvested during two seasons (winter and spring) to monitor the effects of climatic conditions and hydroponic growth systems on fruit quality at harvest. The best fruit quality at harvest, as measured by lightness and hue angle parameters, was obtained during the 3 weeks following the first winter picking. When values of a parameter of preharvest climate value called G^* were lower than 0.4 MJ m⁻² °C day⁻¹ interval⁻¹, the cucumber achieved its optimum quality at harvest, as measured by the dark green color of the skin. NFT-grown fruits showed darker and greener skin color (higher hue angle and lower lightness) compared with perlite-grown fruit, irrespective of the season considered. During the winter season, the plant transpiration rate was 30% higher in perlite than in NFT culture, which correlates with higher differences in G^* and 40% additional yield in perlite. However, in spring G^* was not sensitive enough to discriminate between the two hydroponic systems. In general, fruit quality at harvest in spring was lower than during the winter, due to flesh whitening, higher longitudinal and equatorial calibers, and slightly higher pH, as well as worse epidermal color coordinates (ranging from the dark and dull green color typical of winter fruit to light and a vivid green-yellow color). During the spring season, NFT-grown fruit were less acid than perlite-grown fruit with no apparent correlation with the climatic conditions or fruit nutrition.     

Comparative analysis of autochthonous almond (Prunus amigdalus Bastch) material and commercial varieties in the Castilla-La Mancha Region (Spain)

The Castilla-La Mancha Region is characterized by a large variety of microclimates, allowing the cultivation of species with different climate requirements. While the districts of “Sierra del Segura” and “Campos de Hellín” account for the largest almond growing area in the region. This comparative study is based on the existence of native almond material (local names De Santos and Daniel) which shows kernel morphology and nut quality quite similar to the two most well known commercial varieties of almonds: Marcona and Desmayo Largueta. The identification of this native almond material is of great importance due to its adaptation to local environmental conditions (low temperatures, drought, hot and dry summers) and its morphological similarities with these two almond commercial varieties. A set of 6 Prunus SSR markers were used to identify and differentiate a total of 27 almond samples taken in the “Sierra del Segura” district, including local plant material and material from commercial varieties as a reference. Ten different SSR profiles were discriminated. The number of alleles per locus ranged from seven to twelve with a total of 52 alleles for all loci and an average of 9 alleles per locus. The analysis showed that they share 58% of the studied alleles with one common allele size in both cases for all the SSRs studied. This is the first molecular characterization of native almond germplasm in the Castilla-La Mancha Region. The results provide useful information that could be included in the future almond germplasm bank.     

Development of specific primers for cpSSR analysis in caper,olive and grapevine using consensus chloroplast primer pairs

Chloroplast SSR (cpSSR) markers have demonstrated utility in studying genetic relationships. DNA sequence information of the chloroplast genome is necessary for the development of cpSSR primer pairs. To overcome this limitation, “consensus” primers have been developed to amplify the homologous regions in plants where chloroplast sequences are not available. However, 80% Pinus thunbergi and Nicotiana tabacum developed “consensus” primers tested with grapevine, olive and caper showed multi-locus patterns. The presence of multi-locus patterns requires the use of agarose gel electrophoresis followed from isolation and sequencing of the bands. Herein, a PCR-strategy is proposed to construct specific cpSSR primer pairs without genomic sequence information, giving single-band amplifications that can be directly sequenced. Twelve new specific cpSSR primer pairs were developed for Capparis spinosa L., Olea europea L. and Vitis vinifera L. PCR products were sequenced to confirm the presence of microsatellite sequences, and their transportability was tested on six V. vinifera cultivars. Both single-nucleotide polymorphisms and polymorphic cpSSR were observed in the six grapevine cultivars using the specific cpSSR primers.     

Application of chlorophyll fluorescence for the diagnosis of salt stress in tomato “Solanum lycopersicum (variety Rio Grande)”

To study the response of tomato (Solanum lycopersicum cv. Rio Grande) to salinity, the effect on plant growth, water relations, stomatal conductance and Chlorophyll fluorescence was investigated. Tomato plants were grown in peat culture under controlled conditions and submitted during 28 days to saline stress ranging from 0 to 25, 50, 100, 150 and 200 mM of NaCl. At the end of the experiment period, plant growth was significantly decreased with increasing salinity.