Saffron Corms Research Articles

Molecular adaptation and codon usage bias analysis of Heterodera glycines and Heterodera avenae in saffron (Crocus sativus) corms from Jammu and Kashmir

This study explores the prevalence, distribution, and codon usage bias of nematode species, primarily Heterodera glycines and Heterodera avenae, within saffron corms. Nematode analysis identified H. glycines and H. avenae as the predominant species. Geographical locations exhibited distinct cyst infestation levels, with H. avenae showing higher prevalence. The study reveals the preference of these nematodes for saffron corms, raising concerns for saffron production and suggesting the implementation of monitoring and management strategies. Additionally, the study analyzes the codon usage bias (CUB) of saffron and its associated nematode pathogens. Codon usage bias analysis revealed an AT bias in Crocus sativus and its pathogens. Codon Adaptation Index (CAI) values suggested pathogen adaptation to the host. Correlation analysis highlighted the interplay of nucleotide composition, mutational pressure, and natural selection in codon usage patterns. Amino acid frequency and codon context analyses provided insights into evolution and physiological functions. Furthermore, the study observed a mutual codon preference between the host and pathogens for certain amino acids, highlighting specific interactions at the molecular level. This study provides valuable information for understanding the molecular biology of plant-nematode interactions, and its findings can be useful for developing effective management strategies against these pests in saffron production and other crops such as crop rotation, use of resistant cultivars, and application of nematode-suppressive amendments.

PGPR mediated enhancement of saffron corm production in non-traditional area of Himachal Pradesh, India

In India, saffron (Crocus sativus) cultivation is being extensively promoted in non-traditional areas mainly in Himachal Pradesh and Uttarakhand. In this regard, the availability of good quality planting material (large corms) is a major limitation. Hence, efforts were made to increase the production of daughter corms in farmers’ fields through the application of thermotolerant PGPR FS2 which could retain its growth-promoting potential over a wide temperature regime. The bacterial community was assessed through metagenomic approach. The PGPR FS2 was isolated from the bacterial community associated with the saffron rhizosphere. Stringent screening processes were adopted to select appropriate PGPR to successfully produce bigger-size saffron corms which are of economic importance. The study highlights the positive role of Plant growth promoting rhizobacteria (PGPR) in promoting the commercial cultivation of saffron in nontraditional areas of HP India through organic argopractice.

Isolation, Identification, and Determination of the Virulence of the Causal Agents of Corm Rot of Saffron (Crocus sativus L.) in Valle de Uco, Argentina.

Saffron (Crocus sativus L.) presents an attractive opportunity for diversifying production and adding value, particularly for small-scale growers and family-based agriculture. However, the agamic propagation of the crop through corms raises concerns regarding disease dispersion. During the summers of 2013 and 2015, symptoms of corm rot were observed in saffron crops in La Consulta, Valle de Uco, Argentina. These symptoms manifested in the form of wilting plants and red-coloured areas on the surface of the corms, in some cases affecting deeper regions. This study aimed to isolate and identify the causal agent responsible for saffron corm rot while also comparing the virulence of four strains isolated on saffron plants. Consistent isolation of Fusarium spp. colonies from affected corms confirmed its association with the disease. The obtained isolates were inoculated into healthy corms, and the reproduction of symptoms was confirmed, as well as subsequent pathogen re-isolation. Morphological and molecular characterisation of the strains was performed using rDNA gene sequencing. Furthermore, disease progression was assessed with fitting epidemiological models to empirical data, which served as estimators of fungal strain aggressiveness. The results conclusively identified Fusarium oxysporum Schltdl. as the causal agent of corm rot, and variations in virulence were observed among the strains on the host plant. After basic molecular and pathological studies, it is postulated that the fungal strains possibly belong to the forma specialis gladioli, but further studies are necessary to confirm that. The present study provides findings that highlight the importance of early detection and the preservation of pathogen-free fields to sustain saffron cultivation. These findings may constitute the initial step for future projects aimed at understanding the epidemiology of the disease better, determining the species/races of the pathogen, and developing effective management strategies.

Agronomic ineffectiveness of saffron (Crocus sativus) corms obtained from the vermicomposted medium the previous year when grown in the soil the following year

Agronomic ineffectiveness of saffron (Crocus sativus) corms obtained from the vermicomposted medium the previous year when grown in the soil the following year

Identification and characterization of pathogens causing saffron corm rot in China.

Corm rot is the most important disease of saffron, for which fungi from several genus such as Fusarium spp. Penicillium spp. and Botrytis spp., have been previously reported to be the pathogens. In this research, we used a combination of amplicon sequencing and traditional isolation methods to identify the causal agents, main infection source. The diversity of microbial communities in diseased saffron corms and soil decreased significantly compared with healthy corms and soil. The contents of Penicillium and Botrytis in healthy and diseased corms were similarly high, indicating that them were not directly related to the occurrence of corm rot. But the relative abundance of Fusarium, Cadophora and Fusicolla were significantly higher in the diseased corms than healthy ones. The abundance of Fusarium increased, while the abundance of Oidiodendron, Paraphaeosphaeria and the endophytic beneficial bacteria Pseudomonas decreased, which may relate to the occurrence of the disease. The co-occurrence network diagram showed that the correlation between fungal and bacterial communities was mainly positive. Plant pathogens were relatively abundant in the diseased soil, according to functional gene prediction. At the same time, we also collected 100 diseased corms from the fields in Jiande, where is known as the "hometown of saffron." All isolated pathogenic strains were identified as Fusarium oxysporum through morphological observation and phylogenetic tree analysis of ITS, Tef-1α and β-tubulin. To better clarify the biological characteristics of F. oxysporum, we cultured the isolates at different temperatures and pH values. The optimum temperature for mycelial growth and sporulation was 25°C, pH 6，carbon sources sorbitol and nitrogen sources, peptone. In short, our results suggests that F. oxysporum was the pathogen causing corm rot in Jiande and corms other than soils are the main primary infection source. These new understanding of saffron corm rot will provide the theoretical basis for its better and efficiently management.

Nitrogen leaching and groundwater N contamination risk in saffron/wheat intercropping under different irrigation and soil fertilizers regimes

The ever-rising trend of nitrate leaching from the agricultural production systems is a major risk to the contamination of ground- and surface-waters and should be addressed. But so far, there has been no study on the reduction of nitrate leaching from saffron fields through intercropping. Saffron growers can make a sustainable use of the saffron inter-row spaces through the strategy of winter-wheat/saffron base intercropping system to reduce nitrate leaching. During four years of study, in a set of lysimeters, effects of two cropping systems (saffron mono-cropping and saffron–wheat intercropping), application of two sources of nitrogen (organic cow manure and chemical granular urea) and four irrigation regimes [40, 60, 80, and 100% of the standard crop evapotranspiration (ETc)] on plant nitrogen and phosphorus uptake, nitrogen leaching and nitrogen and phosphorus efficiencies were investigated. The optimum irrigation regime was experienced at 60% ETc (with irrigation application efficiency of 60%, equivalent to 100%ETc) where the highest saffron and wheat nutrient (nitrogen and phosphorus) uptake, nutrient (nitrogen and phosphorus) harvest indices, nutrient acquisition and use efficiencies, corm, saffron, and grain yields and lowest nitrogen loss was achieved. Moreover, manure application indicated 12, 42, 50 and 46% lower amounts of drained water, leachate nitrate nitrogen concentration, total leached nitrogen and N losses (other than N leaching), respectively, in comparison to the urea source of nitrogen showing the lower risk of groundwater nitrate pollution. Manure application showed 9, 8 and 9% increase in the concentration of corm nitrogen, phosphorus and protein, respectively, in comparison to urea application treatment. Saffron corm and stigma yields, irrigation and economic water productivities, corm nitrogen use efficiency and saffron-plant-nitrogen-acquisition efficiency in manure application surpassed respectively by 21, 25, 20, 17, 39 and 49% compared with the chemical source of nitrogen. Intercropping showed 10, 11, 23 and 64% lower amounts of drained water, nitrate concentration in drainage water, seasonal leached nitrate and N losses (other than N leaching), respectively compared to saffron sole cropping which reduces the risk of groundwaters nitrate contamination. For all the experimental treatments, empirical regression models were derived for estimation of seasonal leached nitrate based on the seasonal drained water. Intercropping saffron with winter wheat, application of organic cow manure and adopting irrigation regime of 60% ETc is an innovative system of saffron production which mitigates the risk of groundwater nitrate contamination and increases irrigation and economic water productivities. Saffron growers can make sustainable and clean use of the inter-row spaces of the saffron crop to grow winter wheat in order to obtain higher economic water productivity and lower groundwater nitrate pollution, and it is highly recommended to maintain a sustainable environment.

Biostimulant enhances growth and corm production of saffron (Crocus sativus L.) in non-traditional areas of North western Himalayas.

The usage of seaweed extracts in cropping systems is gaining attention nowadays due to their distinct bioactive properties. This study aims to assess how saffron (Crocus sativus L.) corm production was affected by seaweed extract through different application modes. The study was conducted at the CSIR-Institute of Himalayan Bioresource Technology, Palampur, HP, India, during the autumn-winter agricultural cycle. Five treatments using a combination of Kappaphycus and Sargassum seaweed extracts were replicated five times in a randomized block design. Treatments that were examined include T1: Control, T2: Corm dipping @ 5% seaweed extract, T3: Foliar spray @ 5% seaweed extract, T4: Drenching @ 5% seaweed extract, and T5: Corm dipping + foliar spray @ 5% seaweed extract. Seaweed extract, when applied to saffron plants (T5: Corm dipping + foliar spray @ 5% seaweed extract) resulted in significantly higher growth parameters along with the higher dry weight of stem, leaves, corms, and total roots per corm. Corm production, viz., the number of daughter corms and corm weight per m2 was significantly affected by seaweed extract application, with the maximum value recorded with treatment T5. Biochemical parameters chlorophyll, carotenoids, and photosynthetic rate were higher in T5, while nutrient concentration was lowest in this treatment. Seaweed extracts improved corm production, making it a feasible alternative to limiting the application of conventional fertilizers, attenuating the effects on the environment, and enhancing corm number and weight.

Injury and not the pathogen is the primary cause of corm rot in Crocus sativus (saffron).

Fusarium oxysporum has been reported to be the most devastating pathogen of Crocus sativus L., a commercially significant crop that yields the saffron spice. However, most of the pathogen isolations have been done from the diseased tissue, mostly from rotten corms, but no study has been conducted on diseased saffron fields. To fill the knowledge gap, the current study was carried out with the intention of recording the diversity of cultivable fungus species from saffron fields and screening them for pathogenicity towards saffron. The three study locations in Jammu and Kashmir, Srinagar (Pampore), Kishtwar, and Ramban, yielded a total of 45 fungal isolates. The internal transcribed spacer (ITS) of rDNA was used for the molecular identification. ITS rDNA-based sequence analysis classified all the operational taxonomic units (OTUs) into two phyla-Ascomycota (88.88%) and Mucoromycota (11.11%). Moreover, Fusarium (57.77%), Geotrichum (17.77%), Mucor (11.11%), Aspergillus (4.44%), Trichoderma (4.44%), Galactomyces (2.22%), and Colletotrichum (2.22%) all had different total abundances at the genus level. It was discovered that the saffron fields in Srinagar have fewer varied fungal species than the other two selected sites. All of the fungal isolates isolated including Fusarium solani, Aspergillus flavus, Trichoderma harzianum, Fusarium neocosmosporiellum, and Mucor circinelloides were pathogenic according to the pathogenicity test; however, injury to the saffron plant was found to be a must. These fungi were pathogenic in addition to F. oxysporum, which is well documented as a major cause of saffron corm rot diseases in Srinagar, but in the present study, injury was a must for F. oxysporum as well. The percentage disease severity index for both saffron roots and corms varied for each fungal isolate.

Hurdles and clarifications for the cultivation of saffron in Jammu and Kashmir

Since saffron is a triploid crop, it does not generate seed when selfed or crossed and is passed down through the generations by daughter corms produced from the mother corms. As a result, agro-technology development is the only viable alternative for bringing this crop to its full potential. Saffron does not have any specific habitat preferences, as evidenced by discovering numerous previously unknown saffron farmed areas during the current study. The plant grows as a mixed crop under apple ( Malus domestica Borkh ), almond (Prunus amygdalus Batsch.), populus ( Populus alba L.), and walnut ( Juglans regia L.) trees, as well as in plains, undulated soils, hills, and rice fields. It can be found growing between 1585 and 2050 m above sea level. Different agro-techniques were standardized, among which compost soil (compost 250 gms per pot with 2 kgs of soil; 500 gms per tray with 4 kgs of soil; 10 kgs per bed) was found to be best for early flower production. Soil and farmyard manure (1:3), UDP 0.25 gms/pot (N-115.511+ K130.952+P-58.496 mg), soil DAP 650 mg/2 kg of soil (@P = 152.0899 mg), soil MOP 350 mg/2 kg (@ K = 183.37 mg) of soil was preeminent of procured in vitro raised cormlets in terms of their sprouting and survival of shoots. Corm density was also checked in the offseason of the crop, with growth activity of only saffron corms. Significant negative correlation was recorded with r = 0.82; n = 100; P ≤ 0.001. But the reverse trend was observed in the crop's growing season when most de-weeding and field preparations are accomplished. The study will benefit people in near future as it emphasized the imperative proofs and picture of saffron cultivation in Kashmir valley, reflects the realities of saffron cultivation and trounces the earlier myths. • Saffron is a triploid crop, hence fails to produce seed upon selfing or crossing. It is propagated by daughter corms produced from the mother corms. • Some unfamiliar saffron cultivated sites have also been located. • It grows along an altitudinal gradient of 1585–2050 m asl. i.e. from Nehama (1585 m) Budgam to Buzgow (2050 m)- Nilnag- Gogipathri. • Different agro-techniques were standardized and compost soil (Compost 250 gms per pot with 2 kgs of soil; 500 gms per tray with 4 kgs of soil; 10 kgs per bed) was found to be best with respect to early flower production. • Soil and farm yard manure 1:3, UDP 0.25 gms/pot (N-115.511+ K130.952+P-58.496 mg), soil DAP 650mg/2 kg of soil (@P = 152.0899 mg), soil MOP 350mg/2 kg (@ K = 183.37 mg) of soil was preeminent of procured invitro raised cormlets in terms of their sprouting and survival of shoots up to the second year of their growth period. • Knowledge of weed characteristics, morphology, ontogeny, nature of competition and degree of association with crops are pre-requisite for suggesting some efficient weed control measures. • The data on weeds revealed that most weed species belongs to three families with dominant family Asteraceae, followed by Brasicaceae, Fabaceace and Lamiaceae. • Corm density was checked in off season of the crop, with growth activity of only saffron corms, significant negative correlation was recorded with r = 0.82; n = 100; P ≤ 0.001. But reverse trend was observed in growth season of the crop when most de-weeding and field preparations are going on.

Invasion and Colonization of Pathogenic Fusarium oxysporum R1 in Crocus sativus L. during Corm Rot Disease Progression.

The corm rot of saffron caused by Fusarium oxysporum (Fox) has been reported to be the most destructive fungal disease of the herb globally. The pathogen, Fusarium oxysporum R1 (Fox R1) isolated by our group from Kashmir, India, was found to be different from Fusarium oxysporum f.sp. gladioli commonly reported corm rot agent of saffron. In the present study, Fox R1 was further characterized using housekeeping genes and pathogenicity tests, as Fusarium oxysporum R1 f.sp. iridacearum race 4. Though Fox R1 invaded the saffron plant through both corm and roots, the corm was found to be the preferred site of infection. In addition, the route of pathogen movement wastracked by monitoring visual symptoms, semi-quantitative PCR, quantitative-PCR (q-PCR), real-time imaging of egfp-tagged Fusarium oxysporum R1, and Fox R1 load quantification. This study is the first study of its kind on the bidirectional pathogenesis from corm to roots and vice-versa, as the literature only reports unidirectional upward movement from roots to other parts of the plant. In addition, the colonization pattern of Fox R1 in saffron corms and roots was studied. The present study involved a systematic elucidation of the mode and mechanism of pathogenesis in the saffron Fusarium oxysporum strain R1 pathosystem.

Sugar metabolism mediates temperature-dependent flowering induction in saffron (Crocus sativus L.)

Saffron, which comprises the stigma of the Crocus sativus flower, is an important culinary and medicinal product. Saffron productivity depends on its flower formation, which is regulated by temperature. Inappropriate temperatures at the flowering stages result in flower atrophy and reduced or no flowering. The effect of temperature on saffron flowering was investigated using morphological studies coupled with transcriptomics and metabolic studies of meristem-enriched tissue collected from corms stored and grown at two different temperatures [high (25°C) and low (8°C)] during flowering. Morphological and histological studies suggested that high temperature, during the resting phase of the saffron corm life cycle, promotes flowering, whereas low temperature suppresses it. Low temperatures suppress flowering by inhibiting flower induction. Transcriptome analysis during the flower induction stage indicated that sugar metabolism genes were differentially regulated at different temperatures. Genes coding for starch and sucrose metabolism were enriched and differentially regulated at 25°C vs 8°C. High temperature promoted starch breakdown and soluble sugar formation, whereas low temperature had a vice-versa effect. Further, we identified that low-temperature mediated suppression of flowering involves the downregulation of the floral integrator gene CsatFT3. Exogenous sugar feeding, mainly sucrose, can rescue the low-temperature suppression of flower induction via upregulation of the CsatFT3 gene. Overall the results suggest that environmental temperatures alter sugar metabolism, which mediates temperature-dependent flower induction in saffron corms via regulation of the FT3 gene. These findings will aid in identifying temperature driven molecular factors controlling flowering in saffron.

Microbiome contributes to phenotypic plasticity in saffron crocus.

Saffron crocus is a sterile plant species that propagates vegetatively, and consequently, narrow genetic variation is detected in this species. Besides the narrow genetic variation, there is significant phenotypic variation in different traits in this plant. Here we tested this hypothesis that plant microbiome is a major contributor to the phenotypic variation. We focused our analysis on culturable bacteria that were dominant in saffron fields with high stigma yield compared to the fields with low stigma yield. Following this strategy, four rhizospheric (Cupriavidus metallidurans, Bacillus sp., Solibacillus sp., and Planococcus sp.) and two endophytic bacteria (Serratia oryzae and S. odorifera) were identified. The effects of the bacteria on the growth and development of the model plant Arabidopsis were assessed both in agar plate and pot assays. Results showed that these bacteria influence the vegetative growth and flowering time of Arabidopsis. In the next step, corms of saffron were inoculated with these bacteria and the growth and development of the saffron plants were monitored for five months. Remarkably, inoculation of the bacteria had significant influence on vegetative growth, flowering time, and stigma yield of saffron crocus. Furthermore, one of the bacteria, C. metallidurans, is reported here for the first time as a naturally occurring plant-associated bacteria. Altogether our results suggest that plant microbiome is an important factor in phenotypic variation in saffron crocus.

Study on the interaction mechanism between Crocus sativus and Fusarium oxysporum based on dual RNA-seq.

The saffron phenylpropane synthesis pathway and Fusarium oxysporum cell wall-degrading enzymes play key roles in their early interactions. Saffron (Crocus sativus) is a highly important crop with diverse medicinal properties. F. oxysporum is a widely-distributed soil-borne fungus, causing the serious saffron rot disease. Currently, there is no effective management strategy to control this disease because of no resistant cultivars and limited information about the resistance and pathogenic mechanisms. In this study, we first characterized the infection process and physiological responses of saffron infected by F. oxysporum. The molecular mechanism of these infection interactions was revealed by dual RNA-seq analysis. On the 3rd day of infection, the hyphae completely entered, colonized and spread in the corm cells; while on the 6th day of infection, hyphae had appeared in the xylem cells, blocking these vessels. Transcriptome results indicate that within the host, phenylpropanoid metabolism, plant hormone signal transduction and plant pathogen interaction pathways were activated during infection. These pathways were conducive to the enhancement of cell wall, the occurrence of hypersensitivity, and the accumulation of various antibacterial proteins and phytoantitoxins. Meanwhile, in the fungus, many up-regulated genes were related to F. oxysporum cell wall degrading enzymes, toxin synthesis and pathogenicity gene, showing its strong pathogenicity. This study provides new ideas for the control of saffron corm rot, and also provides a theoretical basis for mining the key functional genes.

Quantifying Saffron (Crocus sativus L.) Leaves and Corms Growth under Natural Saline Conditions

ABSTRACT Saffron is one of the most important industrial water-efficient crops with high economic benefits. However, this precious crop is planted mainly in semi-arid regions, which usually suffer from both fresh water scarcity and soil salinity. Under saline conditions, simulation models help in understanding the crop growth and development. In this pot experiment, quantitative response of saffron was studied to find out if it can be irrigated with brackish water. The experimental treatments were consisted of a tap water (as a control with EC of 0.5 dS m−1) and six natural salinity levels of 1.5, 2, 3, 4, 5, and 6 dS m−1. The effect of imposed salinity levels on three main parameters of vegetative stage of saffron including leaves fresh weight, corm weights, and numbers of daughter corms was then investigated. Accordingly, four macroscopic salinity models were applied and their performances were analyzed. Results for aerial parts (leaves) fresh weight indicated that the van Genuchten and Hoffman model with r and NSE values of 0.99 and 0.83 had higher accuracy than the other three models. Homaee et al. model with r = 0.96 and NSE = 0.72 performed best for the corm weight. For the daughter corm multiplication variable, the Homaee et al. model (r = 0.96, NSE = 0.79) provided a better estimation than the other models. Finally, the measured salinity threshold values of saffron under different growth stages were obtained for the first time. Accordingly the salinity threshold values of Saffron corms and leaves were obtained to be 1.2 and 1 dS m−1, respectively. Thus, these findings can be used for initiating quantitative studies on saffron production under saline conditions.

Studies of Phenotypic and Genotypic Variation for Morphological Traits in Saffron (Crocus sativus L.)

Aims: The “Saffron (Crocus sativus L.)” germplasm was evaluated, based on phenotypic and genotypic variability studies to identify elite divergent traits for economic yield enhancement.
 Study Design: 140 germplasm lines were collected from different saffron growing areas of Kashmir and abroad viz., Afghanistan, Iran. The pedigree details of all samples were recorded. Saffron corms weighing 5g to 16g were planted in Augmented Block Design with a row length, width of 3m, 2m and inter and intra-row spacing of 20 and 10 cms, respectively.
 Place and Duration of Study: The research was conducted at Advanced Research Station for Saffron and Seed Spices (ARSSSS), Pampore, SKUAST-Kashmir during cropping season 2017-18.
 Methodology: Observations were recorded for 15 morphological traits viz., number of flowers corm-1 line-1, number of days to 50% flowering, fresh flower weight corm-1 line-1, inner tepal length, outer tepal length, inner tepal width, outer tepal width, anther length, anther width, style length, stigma length, fresh pistil weight, dry pistil weight, leaf length, number of leaves corm-1line-1. Results: Significant variation was observed for all traits like., number of flowers corm-1 line-1 (4.00-35.33), fresh pistil weight (104.84- 1207.38 mg), stigma length (2.55-4.18 cm), leaf length (16.12-37.10 cm), number of leaves corm-1 line-1 (6.00-11.33), fresh flower weight corm-1 line-1 (1.80-14.31 mg) indicating presence of high level of variability in germplasm.
 Conclusion: The estimates of phenotypic variation were higher than equivalent estimates of genotypic variation except few traits indicating major impact of environment towards expression of a trait. Our findings contributes better understanding of genetic variation in saffron for both vegetative and yield attributes and indicates high level of variability in germplasm, therefore imply considerable scope for saffron improvement through clonal selection.

Comparative Effects of Four Plant Growth Regulators on Yield and Field Performance of Crocus sativus L.

The effects of four plant growth regulators on Crocus sativus L. (saffron) yield and performance were studied in two consecutive years under field conditions. Saffron corms were immersed in solutions of gibberellic acid (GA3), salicylic acid (SA), paclobutrazol (PBZ), chlormequat chloride (CCC), distilled water (hydroprime), and dry corms as the control. Results showed that among the different treatments, plants primed with GA3 500 μM had the highest flower fresh weight and stigma dry weight. In contrast, primed corms with 1000 μM CCC and 100 μM PBZ had the lowest flower dry weight. Furthermore, the plants primed with SA 1400 had the highest leaf numbers, leaf dry weight, and leaf area index (LAI). Plants treated with GA3 induced narrow but the longest leaves, while those treated with SA showed the widest ones. It was also demonstrated that the application of CCC and PBZ can produce shorter leaves. Furthermore, the greatest numbers of daughter corms were obtained in 1400 μM SA. Both PBZ and CCC were reported to have no impacts on the corm numbers but produced larger and heavier daughter corms. The results revealed that the priming of saffron corms with GA3 and then SA improved saffron growth and yield.

Effects of Nutrient Solution Electrical Conductivity on the Leaf Gas Exchange, Biochemical Stress Markers, Growth, Stigma Yield, and Daughter Corm Yield of Saffron in a Plant Factory

Indoor saffron farming systems under controlled conditions are required to meet the high demand for this valuable crop. The aim of the present study was to determine the flowering, growth, and yield responses of saffron grown using nutrient solutions with different electrical conductivity (EC) levels (0.7, 1.4, and 2.1 dS m−1). Sprouted saffron corms were cultured for 24 weeks under a volcanic rock-based aerated continuous immersion system. Vegetative growth and leaf gas exchange, but not flowering, were affected significantly by EC levels. The optimal EC in a balanced nutrient solution was 0.7 dS m−1, at which level the highest plant height, leaf area, biomass, photosynthetic rate, number of daughter corms, and percentage of corms ≥ 25 mm were recorded. An EC level of 2.1 dS m−1 decreased the photosynthetic rate, stomatal conductance, and transpiration rate of saffron but increased biochemical stress marker levels and elevated various antioxidant defense enzyme levels significantly in saffron leaves, possibly reflecting a defense response to the cellular damage provoked by the higher EC level. In terms of nutrient solution EC, 0.7 dS m−1 was optimal in saffron, whereas 2.1 dS m−1 caused oxidative stress that led to reduced growth and daughter corm production.

Molecular and Pathogenic Characterization of Fusarium Species Associated with Corm Rot Disease in Saffron from China.

Saffron (Crocus sativus L.) is a commercial spice crop well-known throughout the world, valued for culinary, colorant, and pharmaceutical purposes. In China, Fusarium nirenbergiae was detected as causative agent of saffron corm rot, the most pervasive disease for the first time in 2020. In the present study, 261 Fusarium-like isolates were recovered from 120 rotted corms in four saffron producing fields at Zhejiang, Shanghai, and Yunnan provinces, China, in 2021. A combination of morpho-cultural features and multilocus sequence analysis (MLSA) of the concatenated rpb2 (DNA-directed RNA polymerase II largest subunit) and tef1 (translation elongation factor 1-α) partial sequences showed that the isolates from saffron belong to Fusarium nirenbergiae as well as F. commune, and F. annulatum with isolation frequencies of 58.2%, 26.8%, and 14.9%, respectively. Notably, F. commune was more prevalent than F. annulatum in the collected samples. Pathogenicity tests confirmed that both species were pathogenic on saffron corm. This is the first report of F. annulatum and F. commune causing corm rot of saffron, globally. Outcomes of the current research demonstrate that Fusarium spp. associated with saffron corm rot are more diverse than previously reported. Furthermore, some plants were infected by two or more Fusarium species. Our findings broaden knowledge about Fusarium spp. that inflict corm rot and assist the development of control measures.

Farklı yetiştiricilik uygulamalarının tarla ve sera koşullarında yetiştiriciliği yapılan safran (Crocus sativus L.) korm verimi ve özellikleri üzerine olan etkileri

Aims: This study aimed to determine the effects of different cultivation practices on yield and characteristics of saffron corm grown in field and greenhouse conditions.Methods and Results: Two different saffron corm sizes, with an average weight of 12 g and 6 g, were used as production material. The cultivation of saffron corms was carried out in areas where 4 different treatments were applied such as silt (fine stream sand), cockpeat, peat + perlite and cockpeat + perlite. Field studies were set up according to the randomized blocks split-plot design experimental design, and greenhouse studies were set up according to the randomized plots design with 3 replications. The highest corm yield, corm increase rate per unit and the harvested corm weight were obtained in field conditions where silt applications were made.Conclusions: In field and greenhouse conditions, silt application has been determined as the most suitable cultivation treatment for the production of corm as seed material in a short time, as well as the corm properties of saffron.Significance and Impact of the Study: It has been demonstrated that the field conditions are more effective than the greenhouse conditions and the silt treatment is more effective than other applications used for saffron corm production.

Effects of Growing Substrate, Mode of Nutrient Supply, and Saffron Corm Size on Flowering, Growth, Photosynthetic Competence, and Cormlet Formation in Hydroponics

Hydroponics is a promising method for cultivation of saffron (Crocus sativus). In this study, saffron corms were sprouted using a gradual decrease in air temperature, and they were cultivated hydroponically in either perlite or volcanic rock for 24 weeks. A nutrient solution was supplied using either an ebb-and-flow system or continuous immersion. First blooming was observed 29 days after transplantation. Among flowering traits, only the stigma length was significantly influenced by the type of hydroponic system. Saffron plants displayed better growth parameters, a higher photosynthetic rate and stomatal conductance (gS), as well as daughter corm (cormlet) production under the continuous immersion system, in comparison with the ebb-and-flow system. Small corms (22–25 mm diameter) did not bloom, and the emergence of flowers increased with corm size. Plant growth and photosynthetic parameters, as well as cormlet production, significantly increased with corm size. We obtained the highest stigma yield [number of flowers (1.9), stigma length (39.4 mm), stigma fresh (42.8 mg), and dry weight (5.3 mg)] and cormlet yield [number of cormlets (5.7), average corm diameter (25 mm), and fresh weight (6.4 g)] using mother corms sized ≥32 mm diameter grown hydroponically in the volcanic rock–based continuous immersion system.