Saffron Yield Research Articles

Yield and quality of saffron (Crocus sativus L.) in response to priming treatments and water deficit

Despite being the most expensive spice, saffron is generally exposed to drought stress during its life cycle. The application of some effective compounds in the plants, can make it strong against environmental stresses such as water deficit. Therefore, the effect of saffron corm priming on the quantitative, qualitative, and physiological responses of this crop under drought stress was investigated in a split-plot experiment as a randomized complete block design with three replicates in two experimental years, 2022 and 2023. The treatments of the on-field experiment included 50 % Field capacity (FC) (equal to 2500 m3ha−1) and 70 % FC (equal to 3800 m3 ha−1) as the main plot and pretreatments (Corm priming) at six levels of KNO3 (3:1000), Indole-3-acetic acid (1 mg l−1), Gibberellin (300 ppm), Silicon dioxide nanoparticles (100 ppm), Hydro-priming (distilled water) and non-priming (control) as sub-plots. The results revealed the increase of petal and stigma dry weights with the application of IAA priming agents under 70 % FC irrigation as compared to 50 % FC. Based on the findings, the petal dry weights decreased, under 50 % FC in the growing season (2022 and 2023), as compared to 70 % FC conditions. Water use efficiency increased significantly with the use of IAA compared to other treatments in the second year. Water deficit led to an increase in leaf proline content and total soluble sugar. The amounts of picrocrocin improved by 5.6 % with decreasing irrigation water from 70 % to 50 % FC in both experimental years. Moreover, the highest amounts of safranal were gained when corms were exposed to IAA. Priming with IAA increased the dry weight of daughter corms compared to other priming treatments. The N and P absorbed by saffron corm decreased to 29.2 % and 28.6 % at 70 % and 50 % FC, respectively. The highest K+ uptake was recorded with the application of IAA under 70 % FC. Overall, this work indicated that an increase in saffron yield and the quality of flowers is associated with an increase in dry weight of daughter corms, ion absorption in corms and the activity of non-enzymatic defense system caused by the application of IAA under different soil moisture.

Microbial interactions modify saffron traits selectively and modulate immunity through adaptive antioxidative strategy: Organic cultivation modules should be trait and crop-specific

Saffron (Crocus sativus L.) is a high-value, low-volume niche cash crop that has the unique ability to synthesize apocarotenoids. Since different biofertilizers are advocated for promoting plant health, we aimed to evaluate the interactions of commercially available microbial inoculants with this unique hysteranthous plant species. We studied the interactive effect of microbial inoculants on agronomical, physiological and biochemical aspects of Crocus growth, corm multiplication and apo-carotenoid biosynthesis. Significant differences in nutrient mobilization potential, induced systemic resistance, plant growth, corm, and stigma yield/quality were detected between the different biofertilizer combinations. The arbuscular mycorrhizal fungi (AMF) + phosphate-solubilizing bacteria (PSB) + potassium-solubilizing bacteria (KSB) combination was the most suitable for enhancing shoot biomass, root depth, and root biomass. Additionally, the average number of flowers per corm, stigma yield, and corm yield were greatest for the same combination. The highest multiplication rate of mother corms and a small corm index were recorded for plants inoculated with Azospirillum + PSB + KSB. Although Azospirillum caused maximum multiplication, the percentage of smaller daughter corms was greater, while the replacement of Azospirillum with AMF resulted in maximum percentage of larger corms. Plant health improved through AMF-mediated microbial interactions, which induced systemic resistance via enzymatic and nonenzymatic mechanisms and increased the uptake of P, K, Cu, Fe, Mn, and Zn. The interrelationship between plant and microbial consortium was complex, causing trait-specific qualitative and quantitative impacts on saffron attributes. Microbial inoculants increased nutrient uptake by saffron plants and triggered biochemical defence response by causing mild stress, making the plant more growth-responsive and better equipped for defence. Microbial interaction increased saffron yield and quality by favourably modulating plant metabolism, majorly overlapping with plant protection mechanisms. However, plant-microbial combinations in an organic production module are trait-specific and should be chosen carefully.

Network preservation analysis to identify transcriptional biomarkers related to flowering in Crocus sativus.

Crocus sativus L. is known as an ornamental geophyte and a source of valuable spice and secondary metabolites. Network preservation module analysis is one of the best approaches to revealing special features of different conditions. It can determine patterns of divergence and conservation between transcriptome data. Herein, we explored the regulatory genes of the flowering process by RNA-Seq data containing flowering and non-flowering samples in gene expression profiles. Persevered module analysis revealed three significant non-persevered modules related to the flowering process, namely pink, green, and blue. Several hub genes associated with non-preserved modules such as PIA1, NAC90, ALY3, Sus3, MYB31, ARF5/MP, MYB31, HD-ZIP, SEP3d, OR_B, AGL6a, bZIP(TGA1) and GRAS were identified. These candidate genes can be considered key diagnostic biomarkers for the flowering process. Here, we also compared two approaches, WGCNA and NetRep for module preservation analysis. The results of these methods were consistent with non-preserved modules. NetRep was a faster (11 times) and more efficient (run more than 10000 permutations for each comparison) method than WGCNA module preservation. Differential expression genes (DEGs) screening showed that many hub genes were downregulated in non-flowering than flowering samples. Our finding revealed regulatory mechanisms of the flowering process in C. sativus as can be developed transcriptional biomarkers which could pave the way for promoting saffron yield via flowering induction.

Revealing the microbial composition changes and relationship with Fusarium caused by rot disease in the Crocus sativus L.

PurposeRot disease caused by Fusarium poses a formidable threat to the growth of saffron (Crocus sativus L.), resulting in substantial damage to both yield and quality. It is paramount to delve into the root causes of rot disease in saffron to optimize both yield and quality. Existing preventive and treatment modalities have exerted deleterious effects on corms and the natural environment. Consequently, the quest for efficacious and eco-friendly methods such as biological control agents has become an urgent imperative.MethodsThe disparate distribution of microbial communities between rhizospheric microorganisms and saffron serves as the foundational exploration for uncovering the underlying causes of rot disease. Samples from various saffron organs and rhizosphere soil were gathered, and the sequencing data from the microbial communities were interpreted using 16S rRNA and ITS gene sequencing methods. This facilitated an in-depth examination of the composition and changes of microorganisms in both healthy and diseased saffron plants.ResultsThe findings indicated rot disease reduced the abundance and diversity of microorganisms in saffron, and the fungal co-occurrence networks were less stable and their communities were more sensitive to rot disease than the bacterial community. Fusarium was the predominant genus in diseased samples, accounting for 99.19% and 89.77% of the communities in diseased leaves and corms. With corms and leaves displaying heightened susceptibility to infection compared to other plant organs. Some of the beneficial bacterial taxa enriched in the diseased plants were also identified in networks, they showed an antagonistic relationship with Fusarium, suggesting a potential for these bacteria to be used in biologically based control strategies against rot disease. These insights could prove invaluable for the development of biocontrol agents aimed at combating this plant ailment.ConclusionThese findings significantly advance our understanding of saffron-microbiome interactions and could provide fundamental and important data for improving saffron yield and quality in the process of sustainable development.

CsERECTA alternative splicing regulates the flowering numbers depending on temperature in Crocus sativus L.

Saffron, utilized for its medicinal properties in its pistils, can significantly boost yield by increasing the flowering numbers. Several strategies have been implemented to enhance saffron yield, but they may not guarantee the consistent inheritance of desirable traits. However, identifying and manipulating the genes responsible for flower production through molecular breeding offers considerable potential for innovating saffron germplasm resources. Here, a comparative transcriptomic analysis of single-flowered and multi-flowered apical buds was performed to mine the key genes. CsERECTA gene (Crocus sativus L. ERECTA, CsER), which has two spliceosomes in saffron: CsER long transcript (CsERlt) and CsER short transcript (CsERst), was identified as a putative regulator of flower production. To elucidate the effect of CsER alternative splicing on the flowering numbers, a series of molecular biology and genetics experiments were conducted. We found the expression of CsERlt decreased by 1.5-fold in multi-flowered apical buds compared to single-flowered apical buds at 22 ℃, while CsERst increased by 6.47-fold in the non-flowering apical buds at 9 ℃. Overexpression of CsERlt and CsERst in Arabidopsis thaliana revealed that CsERlt suppresses flowering numbers and the application of small-molecule inhibitors targeting CsERlt in flowering-competent corms led to a notable enhancement in the flowering numbers, increasing by up to 139.25 %. qRT-PCR and immunohistochemistry assays revealed a widespread expression pattern of CsERlt in various plant structures. The subcellular localization demonstrated that CsERlt predominantly localized at the cell membrane, while CsERst exhibited both at the membrane and cytoplasm. The transcriptomic data and yeast two-hybrid library screening indicated CsER alternative splicing may regulate flowering numbers through the mitogen-activated protein kinase (MAPK) signaling pathway. Taken together, our findings identify a CsER gene associated with flowering numbers in saffron, and its function in modulating flowering numbers is temperature-dependent, and the MAPK pathway may be involved in the regulation of flowering numbers in saffron.

Corm size and planting density affect the yield and longevity of saffron (Crocus sativus L.)

The effect of the corm size of saffron (Crocus sativus L.) and the planting density was determined on a field study for six years. The objective of the present study was to determine the impact of the corm size and planting density on flower and stigma yields. Two corm sizes were used: corms with a diameter up to 2.5 cm and corms with a diameter greater than 2.5 cm, and five planting density: 22, 27, 33, 44 and 67 corms/m2 with planting distances 30, 25, 20, 15 and 10 cm on the plant row, respectively. The results showed that the year (growing season) and the interaction of year (growing season) with corm size affected all the characteristics that were studied. Over the six-year study period, there was a gradual increase in flowering from the first to the third year, followed by a decline in the fifth and sixth years. The yield of larger corms (greater than 2.5 cm) was higher during the first three years, while smaller corms (less than 2.5 cm) produced higher yields in the fourth through sixth years. On the contrary, the planting density, did not significantly affect the characteristics studied over the six years of cultivation and therefore did not affect the stigma yield of saffron. Therefore, corm size together with the environment are important factors that can affect the productivity and the longevity of the crop and should be considered when planting a new saffron cultivation.

Optimizing saffron (Crocus sativus) yield and quality through nutrient inputs and timing

The study was conducted from 2016 to 2020 and involved the application of eight fertilizer treatments. These treatments included single doses of 45 g m−2 of NPK 15–15-15 applied in autumn (A), winter (W), and spring (S); double doses of 90 g m−2 split evenly in autumn-winter (AW), autumn-spring (AS), and winter-spring (WS); and a triple dose of 135 g m−2 split evenly in autumn-winter-spring (AWS). A control group (C) received no fertilizer. The triple dose treatment yielded the most effective results in terms of saffron yield parameters. The number of flowers m−2 in AWS increased from 73.0 in 2017 to 547.6 in 2020, while control exhibited a slight increase from 32.0 in 2017 to 68.1 in 2020. Double dose treatments were also effective in enhancing yield parameters compared to the control. A single dose treatment applied in spring (S) had a limited impact compared to A and W treatments. Over five years, S, A, and W treatments exhibited an average flower number of 97.9 m−2, 181.1 m−2, and 136.1 m−2 respectively. The qualitative characteristics of saffron, including color (crocin), taste (picrocrocin), and aroma (safranal), were not significantly influenced by fertilization treatments. These attributes remained within the natural limits defined by ISO-3632.

Revealing the dynamics of saffron growth: Optimizing corm size and planting depth for increased yield synergies.

Saffron, the "golden spice" derived from Crocus sativus L., is renowned for its richness in secondary metabolites such as crocin and safranal, contributing to its unique properties. Facing challenges like decreasing global production, optimizing cultivation techniques becomes imperative for enhanced yields. Although the impact of factors like planting density, planting depth, spacing, and corm size on saffron growth has been studied, the interaction between corm size and planting depth remains underexplored. This study systematically investigates the interactive effects of corm size and planting depth on saffron growth and yield, providing evidence-based guidelines for optimizing cultivation. A factorial experiment, employing a completely randomized design, was conducted to assess the influence of corm size (05-10g, 10.1-15g, 15.1-20g) and planting depth (10cm, 15cm, 20cm) on saffron yield. Uniform-sized corms were obtained, and a suitable soil mixture was prepared for cultivation. Morphological and agronomic parameters were measured, and statistical analyses were performed using ANOVA and Tukey's HSD test. The study revealed that planting depth significantly affected saffron emergence. The corms sown under 15cm depth showed 100% emergence regardless of corm size (either 05-10g, 10.1-15g, 15.1-20g) followed by 10cm depth corms. Corm dry weight exhibited a complex interaction, where larger corms benefited from deeper planting, while intermediate-sized corms thrived at shallower depths. Similar patterns were observed in shoot fresh weight and dry weight. Specifically, the largest corm size (t3, 15.1-20g) produced the greatest fresh-weight biomass at the deepest planting depth of 20cm (T3), while intermediate-sized corms (t2, 10.1-15g) were superior at the shallowest 10cm depth (T1). The total plant biomass demonstrated that larger corms excelled in deeper planting, while intermediate-sized corms were optimal at moderate depths. This research highlights the intricate interplay between corm size and planting depth in influencing saffron growth. Larger corms generally promote higher biomass, but the interaction with planting depth is crucial. Understanding these dynamics can aid farmers in tailoring cultivation practices for optimal saffron yields. The study emphasizes the need for a coordinated approach to corm selection and depth placement, providing valuable insights for sustainable saffron production and economic growth.

Understanding the Saffron Corm Development-Insights into Histological and Metabolic Aspects.

The reproduction of Crocus sativus L., a sterile triploid plant, is carried out exclusively through corms, whose size determines the saffron yield. The development of daughter corms (DC) is supported by photoassimilates supplied by the leaves as well as by the mother corms (MC). While biomass partitioning during DC development is well studied, growth dynamics in terms of cell number and size, the involved meristems, as well as carbohydrate partition and allocation, are not yet fully understood. We conducted a comprehensive study into saffron corm growth dynamics at the macroscopic and microscopic levels. Variations in carbohydrate content and enzymatic activities related to sucrose metabolism in sources and sinks were measured. Two key meristems were identified. One is involved in vascular connections between DC and MC. The other is a thickening meristem responsible for DC enlargement. This research explains how the previously described phases of corm growth correlate with variations in cell division, enlargement dynamics, and carbohydrate partitioning among organs. Results also elucidated that the end of DC growth relates to a significant drop in MC root biomass, limiting the water supply for the DC growth, and establishing the onset of leaf wilting. The lack of starch accumulation in aged leaf cells is noteworthy, as is the accumulation of lipids. We hypothesize a signaling role of sugars in DC growth initiation, stop, and leaf aging. Finally, we established a predominant role of sucrose synthase as a sucrolytic enzyme in the maintenance of the high flux of carbon for starch synthesis in DC. Together, the obtained results pave the way for the definition of strategies leading to better control of saffron corm development.

Bioactive compounds and apoptotic effects of saffron (Crocus sativus L.) in different fertilizer conditions

In this study, the qualitative traits of stigma (crocin, picrocrocin and safranal content) and the apoptotic effects of stamen and petal extracts (real-time PCR analysis for evaluating the expression of Bax, Bcl2, CAS3 and CAS6 genes) of saffron were investigated under organic and conventional conditions at the Agricultural Research Field of the University of Birjand, Iran over three years. The treatments included field age (one, two, and three-year-old farm) and also organic and conventional cultivations with different levels (low, moderate, and high levels) of cow manure and chemical fertilizers, respectively. The results indicated that the crocin, picrocrocin and safranal contents were considerably increased using organic and chemical fertilizers compared to the control. The highest crocin, picrocrocin and safranal contents were obtained under applying a high level of manure in organic farming system (OFS-H), that safranal content in this level have no significant difference with applying a moderate level of manure in organic farming system (OFS-M), and applying a high level of chemical fertilizers in conventional farming system (CFS-H). Among the field ages, the three-year-old farm resulted in the highest qualitative yield of saffron compared to the one-year-old farm and the two-year-old farm. The real-time PCR analysis also showed that petal and stamen extracts led to up-regulation of Bax, CAS3 and CAS6 (Pro-apoptotic genes) and down-regulation of Bcl2 (Anti-apoptotic gene) in both cultivation ways. The highest and the lowest bioactive compounds and the expression of Pro-apoptotic genes belonged to stamen extract at organic farming system and petal extract at conventional farming system, respectively. The findings of this study could significantly contribute to identification of the best crop management strategy for increasing the qualitative and medicinal properties of Saffron.

Molecular warfare between pathogenic Fusarium oxysporum R1 and host Crocus sativus L. unraveled by dual transcriptomics.

Phenylpropanoid biosynthesis and plant-pathogen interaction pathways in saffron and cell wall degrading enzymes in Fusarium oxysporum R1 are key players involved in the interaction. Fusarium oxysporum causes corm rot in saffron (Crocus sativus L.), which is one of the most devastating fungal diseases impacting saffron yield globally. Though the corm rot agent and its symptoms are known widely, little is known about the defense mechanism of saffron in response to Fusarium oxysporum infection at molecular level. Therefore, the current study reports saffron-Fusarium oxysporum R1 (Fox R1) interaction at the molecular level using dual a transcriptomics approach. The results indicated the activation of various defense related pathways such as the mitogen activated protein kinase pathway (MAPK), plant-hormone signaling pathways, plant-pathogen interaction pathway, phenylpropanoid biosynthesis pathway and PR protein synthesis in the host during the interaction. The activation of pathways is involved in the hypersensitive response, production of various secondary metabolites, strengthening of the host cell wall, systemic acquired resistance etc. Concurrently, in the pathogen, 60 genes reported to be linked to pathogenicity and virulence has been identified during the invasion. The expression of genes encoding plant cell wall degrading enzymes, various transcription factors and effector proteins indicated the strong pathogenicity of Fusarium oxysporum R1. Based on the results obtained, the putative molecular mechanism of the saffron-Fox R1 interaction was identified. As saffron is a male sterile plant, and can only be improved by genetic manipulation, this work will serve as a foundation for identifying genes that can be used to create saffron varieties, resistant to Fusarium oxysporum infection.

Propagation of Saffron (Crocus sativus L.) Using Cross-Cuttings under a Controlled Environment

Saffron (Crocus sativus L.) is a valuable geophyte plant and one of the most expensive spices in the world. Recently, the demand for saffron spice has increased in worldwide markets owing to its enormous application and value. However, the production of saffron is limited by the vegetative propagation technique and the limited number of high-quality corms planted. Furthermore, climatic changes, notably increasing temperatures, negatively influence saffron multiplication and growth. Thus, it is important to develop alternative cultivation and propagation techniques for saffron under a controlled environment, which could ensure an increase in saffron yield and avoid the negative impact of climatic changes. The present study aimed to develop an alternative method for vegetative propagation of Crocus sativus under controlled conditions. The effect of different cross-cuttings, including basal cuttings (BCs) and top-to-bottom cuttings (CTBs), was evaluated on shoot, leaf, flower, and daughter corm production. All the growth parameters examined were influenced by the cutting treatment applied. The results showed that the highest number of shoots formed was obtained by BCs and CTBs, with an average of 6.68 and 5.47 shoots per corm, respectively, compared to the control with an average of 2.70 shoots per corm. The cutting treatment positively affected the formation of daughter corms in which, the high mean number of corms recorded was obtained by the BC treatment. Meanwhile, the lower size of the daughter corms was obtained after the cross-cutting treatment. This is the first report that provides an alternative propagation for saffron using a controlled environment, which could help to improve the production of saffron.

Water footprint and production of rain-fed saffron under different planting methods with ridge plastic mulch and pre-flowering irrigation in a semi-arid region

Most of the saffron cultivation areas in Iran are irrigated and with pre-flowering irrigation being necessary to facilitate flower emergence. However, the growers face shortage of water. Post- flowering rain-fed (PFRF) saffron cultivation could be a solution, and ridge and furrow rainfall harvesting (RFRH) with plastic mulch could be used to collect runoff in the field planting areas. In this regard, the objectives of this study were to determine the effects of interaction of two different saffron planting methods (basin and furrow planting), using plastic mulch and without plastic mulch on ridge of the furrow planting, using irrigation at pre-flowering and without irrigation on saffron growth, yield, yield components, economic water productivity (EWP) and water footprint of saffron in two growing seasons with low (167 mm) and high (367 mm) seasonal rainfall in a semi-arid region. Without irrigation in pre-flowering (NPFI) produced a saffron yield reduction of 70% compared with pre-flowering irrigation (PFI). It is concluded that 90 mm of irrigation water should be applied as PFI for adequate flowering and yield. In addition, the use of the RFRH system resulted in a runoff coefficient of 0.85 and increased soil water storage (48% at low seasonal rainfall), saffron yield (51%), leaf dry matter, LDM (90%) and EWP (17%). The blue water footprint (BWF) with low rainfall (165 mm) was higher than that with abundant rainfall (367 mm), because saffron yield in the second year was lower due to the older age of saffron in field, which resulted in lower yield and consequently higher BWF. Likewise, green water footprint (GWF) was higher (4810 m3 kg−1) than those that obtained as BWF (739 m3 kg−1) due to the fact that pre-flowering irrigation is necessary for onset of flower and the regional rainfall is insufficient to initiate flowering. The effects of low seasonal precipitation (less than 200 mm) on saffron were manifested in yield and LDM reduction of 70% and 42%, respectively, compared to high seasonal precipitation, decreasing as seasonal precipitation increased. Precipitation reached around 300 mm in rain-fed with pre-flowering irrigation caused no reduction in saffron yield and LDM. Therefore, in PFRF conditions, furrow planting with ridge plastic mulch and pre-flowering irrigation is recommended. The economic water footprint of saffron under PFRF conditions with PFI was 50% of that obtained for irrigated saffron production, which is preferable in virtual water trade.

Simulation of saffron growth using AquaCrop model with high-resolution measured data

Saffron is one of the most expensive and worth-to-cultivate crops in countries struggling with water scarcity due to its low water requirement and compatibility with arid climates. This study was conducted to calibrate and validate the AquaCrop model for saffron at the research farm of the Ferdowsi University of Mashhad (FUM), Iran, in two growing seasons of 2021–2022 (two-year-old saffron) and 2022–2023 (three-year-old saffron). The soil water content, canopy cover, and biomass values were measured continuously during both growing seasons. The field measurements of the first and second growing seasons were used to calibrate and validate the AquaCrop model, respectively. Furthermore, using the Particle Swarm Optimization (PSO) algorithm, a new module for the inverse solution of the AquaCrop model has been presented. The module was successfully employed to fine-tune sensitive soil parameters of the field. The results showed that the AquaCrop model could accurately simulate soil water content, biomass, and canopy cover in both growing seasons. The root mean square error (RMSE) of simulations for soil water content, biomass, and canopy cover comparing to in-situ measured data was 8.3 mm, 0.3 ton ha−1 and 3.4% for the first year and 5.5 mm, 0.4 ton ha−1 and 2.7% for the second year, respectively. In these simulations, the saffron daughter corm production was considered as the crop yield, because the stigma yield is affected by the climatic conditions of the past year while corms are produced at the end of the prevailing season. To investigate the effect of cold and heat on saffron yield, the hottest and coldest growing seasons in the past 30 years were determined in 6 regions besides Mashhad, and the biomass in these seasons was simulated using the model. It was concluded that the cold growing season had a more significant effect than the hot season in reducing the saffron corm yield.

Genetic variability assessment of indigenous and exotic saffron germplasm through morpho-agronomic characterization at Jammu and Kashmir, India

AbstractThe present study analysed a total of 272 saffron (Crocus sativus L.) genotypes using multivariate analysis. We carefully observed and recorded information about the floral, morphological and corm attributes. Significant variations were observed among the genotypes for all the traits, indicating a high level of variability and suggesting a great potential for saffron improvement. The phenotypic variances were found to be greater than the estimated genotypic variances. Descriptive data on various morphological traits revealed significant differences in the frequency of phenotype classes as well as a wide distribution range. The high heritability estimates were observed in average number of daughter corms per plant (ANDCPP), initial weight of corms (IWC g), no. of buds/corm (NBPC), – no. of leaves in main sprout, (NLMS), number of sprouted buds per corm (NSBpC) and total number of leaves (TNL), whereas average weight of daughter corms per plant (AWBCPP), corm diameter (CDcm), pistal length (PL) cm, style length (STYLcm), fresh weight of pistals per plant (FWOPPPmg) and stigma length (STML cm), revealed medium sense of heritability. The traits dry weight of pistals per plants (DWOPPP mg), inner tepal width (ITW cm), leaf length (LLcm), number of flowers per corm (NFpC), outer tepal length (OTLcm), parianth length with tube (PLWT cm) and weight of stigma (WSTG mg) exhibited low broad-sense heritability. Principal component analysis (PCA) divulged that the first eight component characters had an eigenvalue greater than one with a contributory cumulative variance of 66.15% to the total variance, while as rest of the 16 components contributed 33.85% of total variation in a set of 272 genotypes of saffron. The eigenvalues for yield attributing traits for significant PCs ranged from 5.48 (PC1) to 1.03(PC8). The current study has revealed that there was a sufficient variability in a set of saffron germplasm lines which forms the basis for performance-based clonal selection. Moreover, identified elite genotypes based on saffron yield and corm attributes could be used in the saffron breeding programme for the development of saffron varieties.

Climate and management factors influence saffron yield in different environments

AbstractThe economic yield of saffron (Crocus sativus L.) has a wide range in different parts of the world, and it is not clear why this considerable difference exists. In this research saffron yield and yield components of 13 fields with varied geographic and climatic conditions were studied to determine which factor(s) are more important. Among the studied factors, temperature, field age, soil texture, bulk density, soil and water pH, irrigation events, and growth period had the greatest effect on saffron yield. The highest dry stigma weight, as economic yield, was obtained in three regions of Birjand (27 kg ha−1), Sarayan (24 kg ha−1), and Golshan (23.5 kg ha−1), followed by Neyshabur (18 kg ha−1) and Kashmar (17.5 kg ha−1), which had lower temperatures, coarse soil, balanced soil, and water pH, and longer growth periods. The average yields were increased until the sixth or seventh year (20.8 kg ha−1) and then decreased, however, it seems to be economic before the 10th year. Lower temperatures in early fall were important to stimulate flowering and increase yield in that year, and warm and sunny days in the spring are important for next year yields. We found that the optimal temperature for the first irrigation is ∼16°C and for flowering is ∼5°C–10°C. High‐yield fields did not have higher irrigation water volumes but more irrigation events (6.3), resulting in less water volume per irrigation. No direct relationship was observed between manure consumption and yield; however, processed manure increases yield by improving the soil structure and moisture retention ability. Fields with a complete chemical fertilizer composition had higher yields. It was concluded higher yields are achieved in saffron fields where regions are higher in altitude (at least 1300 m) and lower temperature in early autumn with complete fertilizer composition (especially sulfur and iron). There was no evidence of high salinity sensitivity of saffron.

Improved growth and quality of saffron (Crocus sativus L.) in the field conditions through inoculation with selected native plant growth-promoting rhizobacteria (PGPR)

The use of bioresources such as bio-fertilizers especially those containing plant growth promoting rhizobacteria (PGPR), may be a strategy for sustainable agriculture that respects the environment while ensuring optimal plant growth. The objective of this study was to investigate the effects of selected PGPR strains on the growth, yield and quality of saffron. The bacteria tested were isolated from the saffron rhizosphere and selected for important plant beneficial activities (phosphate solubilization, siderophore, and auxin production). The best strains were identified by 16S rRNA gene sequence analysis. Strains S11P1 and S11A1a were identified as Rahnella aquatilis, while strain S12S4 belonged to the species Variovorax paradoxus. An inoculation field experiment was conducted in a 1575 m2 field area in Taliouine (Morocco). Four different inoculants were set-up: the three single selected strains and their mixture. Using the PGPR isolates as inoculum affects positively different saffron plant parameters, such as the number of leaves (28.87 ± 6.1 vs. 22.47 ± 8.19 for control treatment) and chlorophyll content. Underground parts, in particular, daughter corms production was significantly increased about 1.91 times more than the control. In addition, the quality of inoculated saffron was in accordance with the category I specifications (Crocin > 200, Picrocrocin > 70 and Safaranal >20). Overall these results bode well the possibility of using these rhizobacteria, and specially the treatment T2 (Rahnella aquatilis S11P1), as effective biofertilizers for saffron organic cultivation.

Alteration of Flower Yield and Phytochemical Compounds of Saffron (Crocus sativus L.) by Application of Different Light Qualities and Growth Regulators

Saffron is the world’s most coveted spicy plant that has medicinal value. Currently, due to diverse types of difficulties in growing this plant outdoor, the tendency to produce it indoor has been increased. Optimized indoor conditions for growing saffron plants is not fully determined so far. This study was conducted to investigate the interactive effects of two plant growth regulators (PGRs), including gibberellic acid (GA3) and γ-aminobutyric acid (GABA) and four light recipes, including white, monochromatic blue, monochromatic red, and a combination of 50% red and 50% blue on the flower yield and phytochemical components (such as crocin, picrocrocin and safranal) in stigmas of indoor-grown saffron. The results showed that exogenous GABA application and combined red and blue LED lights enhanced the performance of saffron flowers in terms of the number of flowers (up to 1.97 per corm) as well as the fresh and dry weight of flowers and stigmas. In saffron, the concentration of three major secondary metabolites is of great importance since it determines its commercial, pharmaceutical quality. GABA induced saffron’s chemical ingredients toward the phytochemicals safranal (up to 5.03%) and picrocrocin (up to 15.8%), while GA3 induced them toward the carotenoid pigment crocin (up to 25.1%). In conclusion, the application of GABA with a combination of red and blue lights enhanced the production of high-quality stigmas and positively affected the yield of flowers in saffron plants.

Growth and production response in saffron-chickpea intercropping under different irrigation regimes

The present study aimed to evaluate saffron production in intercropping with chickpea under different irrigation regimes. The experiment was a split plot based on a randomized complete block design with three replications during two years (2018–19 and 2019–20). The main plot consisted of two irrigation regimes [i.e. one-time and conventional irrigations], and the sub-plot included eight planting ratios [i.e. saffron mono-crop (C1), chickpea mono-crop (C2), 100% saffron + 50% chickpea (C3) and 100% saffron + 100% chickpea (C4) as additive ratios, and 1:1 (C5), 2:2 (C6), 2:1(C7), and 3:1(C8) saffron:chickpea as replacement ratios]. Based on the results, the effect of the irrigation regime was not significant on flower number, fresh weight of flower, and dried stigma yield of saffron. In intercropping ratios, the highest flower number (141.5 ± 4.26 m−2), fresh weight of flower (108.22 ± 3.4 g m−2), and dried stigma yield (4.1 ± 0.01 kg h−1) were observed in saffron mono-crop and approximately equaled by C3 treatment. The conventional irrigation regime increased the pod and seed numbers, the grain and biological yields, and the harvest index of chickpea. In the intercropping ratios, the maximum aforementioned traits were obtained by chickpea mono-crop. The maximum total land equivalent ratio (1.86) was obtained by the C3 treatment, which showed an intercropping advantage as compared to mono-crop. In summary, the C3 treatment showed the same effects as the mono-crop treatment on the saffron parameters, therefore, this treatment could be considered a proper alternative combination as compared to mono-crop for improving environmental resources absorption and soil fertility.

Influence of Corm Weight and Planting Distance on Production of Saffron in Agro-climatic Condition of Kabul

The effect of phosphorus and plant density on floral yield and corm production of Crocus sativus was studied at horticulture department, faculty of agricultural Kabul University during 2019-2020. Four different phosphorus (P) doses i.e. 0, 20, 40 and 60 kg ha-1 were applied to five different densities viz. 242, 107, 54, 30 and 20 plants m-2. The experiment was laid out in randomized complete block design with split plot arrangements. P effect was largely non-significant, whereas planting densities had considerable effects. Maximum days to sprouting (29.8), and in the second year maximum saffron yield ha-1 (10.4 kg) were produced by 242 plants m-2, while minimum in these were recorded at 20 plants m-2 density. Maximum stigma weight (5.33 mg), Maximum flowers size (3.8 cm) was produced by 30 plants m-2 density at 20 kg ha-1 P, and maximum flowers per plant (1.5) were produced by 20 plants /m-2 densities at 20 kg ha-1 P. Minimum flowers per plant (1.0) were produced by corms at 107 plants m-2 density supplied with 60 kg ha-1 P, and minimum flower size (2.8 cm) was observed in plants grown at 54 m-2 density fed with 40 kg ha-1 P.