Growth and flowering response of Lagurus (Lagurus ovatus L.) to Ascophyllum nodosum extract based biostimulant and gibberellic acid (GA3) application

Ritika Manhas; Arvinder Singh; Nomita Laishram; Shriya Gupta; Kedar Mahadev Gheware; Gurdev Chand; B K Sinha; Vikas Gupta

doi:10.1186/s12870-026-08098-5

. 2026 Jan 28;26:362. doi: 10.1186/s12870-026-08098-5

Growth and flowering response of Lagurus (Lagurus ovatus L.) to Ascophyllum nodosum extract based biostimulant and gibberellic acid (GA₃) application

Ritika Manhas ¹, Arvinder Singh ^1,^✉, Nomita Laishram ¹, Shriya Gupta ¹, Kedar Mahadev Gheware ¹, Gurdev Chand ², B K Sinha ², Vikas Gupta ³

PMCID: PMC12924620 PMID: 41606716

Abstract

Background

Lagurus (Lagurus ovatus L.) is an important ornamental annual grass with fluffy flower heads that are in high demand in the dry flower industry. The stems of Lagurus are frequently used in floral arrangements and dried flower crafts. The utility of this flower in the dry flower industry cannot be underrated. Despite the huge demand for this flower, the economic returns obtained from its sale are comparatively low, which is mainly due to the production of short stems and smaller heads that fetch low prices in the market. Therefore, a field experiment was undertaken in factorial randomized complete block design (RCBD) with two factors and three replications. The key objectives of the experiment was to assess the influence of different seaweed extracts containing Ascophyllum nodosum (control, 2 ml L⁻¹ and 4 ml L⁻¹) and GA₃ (control, 150 ppm, 250 ppm, 350 ppm and 450 ppm) on the growth and flowering of lagurus. The seaweed extract was applied both as a drench and foliar spray.

Results

A higher dose (4 ml L⁻¹) of seaweed extract performed superior in most of the vegetative and flowering traits including number of inflorescences per plant and flower head length. However, highest plant height and stem length was recorded in control plants without any seaweed extract. Among the tested GA₃ doses, the concentration of 450 ppm produced maximum plant height, number of inflorescences per plant, flower head length and stem length. However, GA₃ application at 350 ppm resulted in the highest root dry weight and root: shoot ratio, while maximum root fresh weight were found with GA₃ at 250 ppm. An increase in GA₃ dose resulted in a linear increase in growth and flowering parameters.

Conclusion

The study demonstrated that a higher dose of seaweed extract (4 ml L⁻¹) significantly improved vegetative growth, flowering, and yield-related traits. Similarly, GA₃ application enhanced plant performance in a dose-dependent manner, with 450 ppm GA₃ showing the best overall results for growth and flowering, while 350 ppm optimized root dry weight and root-to-shoot ratio. Overall, the interaction of seaweed extract at 4 ml L⁻¹ and GA₃ at 450 ppm proved most effective for achieving superior plant growth and productivity in lagurus.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12870-026-08098-5.

Keywords: Lagurus ovatus; gibberellic acid (GA₃), Seaweed biostimulant, Ascophyllum nodosum, Flowering traits

Introduction

Lagurus ovatus L. is an ornamental winter annual grass which belongs to Poaceae family. It grows upto 30–50 cm tall under optimum environmental conditions [1, 2]. This hardy, clump-forming grass features attractive panicles suitable for garden borders and are much demand in dry flower industry where dry stems are used in bouquets, arrangements, and decor [3, 4]. In India, production is regionally limited to meet the domestic demand, where longer stems and larger flower heads command premium market prices. Optimization of growth and flowering traits in such ornamental grasses is essential to meet market standards, particularly under sustainable production systems. In this context, the use of plant biostimulants and plant growth regulators has gained considerable interest as an eco-friendly approach to improve plant performance.

Seaweed extract-based biostimulants, particularly those derived from Ascophyllum nodosum, are recognized for their ability to enhance plant growth, nutrient uptake, stress tolerance, and physiological activity through the presence of bioactive compounds such as amino acids, polysaccharides and phytohormones particularly auxin-like compounds, cytokinins, gibberellins and betaine. It can also be used as an alternative to synthetic fertilizers to improve crop yields [5–7]. It was also reported earlier that seaweeds are a source of organic osmolites, amino acids, mineral nutrients and vitamins that helps in adaptation of plants to stressful conditions [5, 8, 9].

The extracts of brown seaweeds are extensively utilized in horticultural crops due to their ability to promote plant growth and enhance crop tolerance to abiotic stresses; including salinity, extreme temperatures, nutrient deficiency, and drought [10] and to foster the development and strengthen the quality performance of floricultural crops [11]. Studies conducted by various workers reported positive effects of seaweed extract in various ornamental crops and grasses [12–21]. However, to maximize the bio stimulant effects, the correct concentration must be used [15].

Similarly, gibberellic acid (GA₃) is a well-known plant growth regulator that plays a pivotal role in cell elongation, stem growth, and floral initiation, thereby influencing both vegetative and reproductive development. Gibberellic acid is known to trigger transitions from juvenile to adult stage, vegetative to flowering as well as grain development [22]. Many studies on growth promotion with GA₃ present an insight into its role in floral transition and elongation of stem and enhancement of flowers size [23].

Despite the widespread use of GA₃ to modulate growth and reproductive traits in many ornamentals, its specific effects on Lagurus ovatus remain largely unexplored. Existing literature primarily focuses on agronomic cereals or a limited number of ornamental species, leaving a clear knowledge gap regarding optimal GA₃ concentrations and their physiological impacts on L. ovatus.

Although the individual effects of seaweed extracts and GA₃ have been widely reported in various ornamental and crop species, information regarding their combined or comparative influence on Lagurus ovatus remains limited. Therefore, the present study addresses this gap by systematically evaluating the growth and flowering response of Lagurus ovatus L. to the application of an Ascophyllum nodosum extract and gibberellic acid. The research aims to assess their effects on key vegetative growth parameters, flowering behavior, and overall plant quality, with the intent of identifying effective treatment strategies for improving the ornamental value and commercial potential of Lagurus ovatus.

Methodology

Experimental site and location

The study was conducted at the Experimental Farm of the Division of Floriculture and Landscaping, Sher-e-Kashmir University of Agricultural Sciences and Technology of Jammu, Jammu and Kashmir, India during the year 2023–2024. The experimental site is situated at an elevation of 296 m above mean sea level (MSL) and at a latitude of 33°55′ North and longitude of 74°58′ East. The area experiences subtropical climate with hot dry summer, hot and humid rainy season, and cold winter. Meteorological data recorded during the cropping period shows that average rainfall ranges between 0.24 mm to 3.23 mm and minimum and maximum temperature ranges between 5.95 °C to 31.99 °C. Relative humidity during the period ranges from 42.13 to 91.97 percent.

Plant material

The seeds of Lagurus ovatus were obtained from the Division of Floriculture and Landscaping, Faculty of Horticulture and Forestry, SKUAST-J, main campus, Chatha.180009.

Nursery preparation

A nursery bed measuring 1.25 m × 3 m was prepared, with thorough hoeing and weeding. The bed was elevated 15 cm above ground level to facilitate proper drainage of excess water. Well composted farmyard manure was incorporated into the bed and seeds were sown in the mid of October month by line sowing method. The seeds were sown in rows 5 cm apart and at a depth of 2–3 cm. The opened rows were filled with a mixture of farmyard manure, soil, and sand in a 2:1:1 ratio. Nursery beds were mulched with straw and then watered using a fine rose can. Once the seed sprouted, the mulch was removed.

Field preparation, transplanting and aftercare

A preliminary study of the soil of the experimental field was conducted before initiation of the experiment for the physio-chemical properties. The composite soil samples were subjected to laboratory analysis for Soil pH, EC, available N [24], available Phosphorous [25] and available Potassium [26] and Organic carbon [27]. The physio-chemical characteristics revealed sandy loam textural class with available N of 256.85 kg. ha⁻¹, available P₂O₅ of 29.40 kg. ha⁻¹, available K₂O of 193.76 kg. ha⁻¹, EC of 0.93 dS.m⁻¹ and organic carbon content of 0.8%.

The experimental field was conditioned to a fine tilth by ploughing 2 to 3 times using a tractor equipped with a rotavator. After removing plant residues and weeds, the field was levelled. Subsequently, beds of the necessary dimensions were made as per the layout plan.

Healthy seedlings having fully expanded 4 leaves were transplanted in the experimental plots at a spacing of 30 cm × 30 cm, accommodating 9 seedlings per bed of dimensions 1 m x 1 m. To minimize transplanting shock, transplanting was carried out during the cooler evening hours. Immediately after transplanting, light irrigation was given. To ensure full plant population, mortality if any in the transplanted seedlings was replaced with fresh seedlings during the first ten days after transplanting. After the establishment of transplanted seedlings, standard intercultural operations were followed.

Experimental design

The experiment was laid out in factorial randomized complete block design with two factors and three replications. Treatments comprised three levels of seaweed extract soil drenches (untreated control, 2 ml L⁻¹ and 4 ml L⁻¹) and five levels of foliar sprays of Gibberellic Acid (untreated control, 150 ppm, 250 ppm, 350 ppm and 450 ppm).

Administration of treatments

The commercial seaweed extract BIOVITA® (PI Industries Ltd., Gujarat, India) was purchased from the market and used for the experiment. It is a commercial formulation of brown algae Ascophyllum nodosum, which contains 200 ppm sulphur, 500 ppm magnesium, 500 ppm calcium, 5000 ppm sodium, 20 ppm boron, 20 ppm iron, 1 ppm manganese, 1 ppm copper, 5 ppm zinc and traces of cytokinins, auxins, proteins and amino acids. As per the label, the recommended dose for any crop is given as 2 ml L⁻¹.

Seaweed extract was prepared in three concentrations of 0-, 2- and 4-ml L⁻¹ by diluting the commercial formulation with water. Seaweed extract was given as soil drench at 30, 60 and 90 days after transplanting. Control plants were drenched with water.

For administration of gibberellic acid, commercial formulation of gibberellic acid (CDH® Pvt. Ltd., New Delhi, India) was used. Gibberellic acid was prepared in five concentrations of 0, 150, 250, 350, 450 ppm. The plants were sprayed with gibberellic acid at 30, 60 and 90 days after transplanting. Control plants were sprayed with water. All the plants received thorough spray from the top to the ground level till runoff.

The concentrations of GA₃ used in this study were based on previous reports in ornamental and grass-like species, where both positive and negative effects at higher doses have been documented. In Solidago canadensis, GA₃ at 100–200 ppm was reported to be optimal for growth and flowering [57]. Nevertheless, a higher dose (up to 450 ppm) was included to evaluate dose-dependent responses under different experimental conditions, as GA₃ effects may vary with species, growth stage, application method, and environment.

Measurement of growth and flowering parameters

The data on various morpho-floral parameters were recorded for each treatment by randomly selecting five plants per treatment per replication. Plant height and plant spread were measured at peak flowering stage. The length and width of uppermost leaf was measured as flag leaf length and width respectively. Leaf area was determined by using a Leaf area meter 211 (SYSTRONICS® India Ltd.) during peak flowering stage. The sampling of leaf was done from the top, middle and bottom of the plant and the average was calculated. The chlorophyll content of leaf was recorded at 30, 60, and 90 days after transplanting with the help of a SPAD—502 chlorophyll meter (Minolta Corporation Ltd., Osaka, Japan) on three newly expanded leaves and three fully matured leaves separately and averaged at each group.

At full maturity, the representative plants were uprooted for destructive sampling. Plant parts were separated into roots and shoots. Fresh weight of each part was determined immediately after harvest, and the plant parts were dried in a hot air oven at 52 °C for 24 h until a constant weight was obtained. After drying, the shoot and root weight was calculated. The root: shoot ratio on a fresh and dry weight basis was derived to denote the ratio of water-absorbing area (root) and the transpiration area (shoot) of a plant and was calculated.

Statistical analysis

The data pertaining to the growth and flowering parameters were analysed using analysis of variance (ANOVA) to test the significance of the data recorded. The means were compared with Duncan’s Multiple Range Test at 5% probability where ANOVA indicated significant differences. The analysis was conducted using SPSS analytical package (IBM SPSS Statistics 27.0.1). Correlation and principal component analysis for various parameters were worked out using R-software package for data analysis.

Results

Growth traits

The results indicate that both seaweed extract and GA₃ treatments significantly affected growth attributes (Table 1, 2). The maximum plant height recorded was 69.13 cm with the application of 0 ml L⁻¹ seaweed extract and 450 ppm GA₃. Furthermore, the combination of 4 ml L⁻¹ seaweed extract combined with 450 ppm GA₃ resulted in notable increase in plant spread (49.20 cm) and leaf number (320.67). However, the effects on flag leaf length, flag leaf width, and leaf area did not show any significant results.

Table 1.

Effect of seaweed extract and GA₃ on vegetative traits of Lagurus ovatus L.

	Plant height (cm)			Plant spread (cm)			Number of leaves per plant
Gibberellic acid dose	Seaweed extract (SWE) drench			Seaweed extract (SWE) drench			Seaweed extract (SWE) drench
	Untreated control	2 ml. L⁻¹	4 ml. L⁻¹	Untreated control	2 ml. L⁻¹	4 ml. L⁻¹	Untreated control	2 ml. L⁻¹	4 ml. L⁻¹
Untreated control	32.84 ± 0.91 h	37.61 ± 1.94 g	37.45 ± 2.19 g	36.90 ± 2.96 a	40.70 ± 1.31 bc	42.53 ± 1.17b	202.13 ± 2.01 g	259.00 ± 9.56 ef	290.67 ± 2.72c
150 ppm	53.11 ± 4.16ef	49.79 ± 1.82 f	49.24 ± 1.32 f	38.52 ± 2.63 cd	40.43 ± 1.50bc	41.90 ± 0.72bc	252.67 ± 1.36 f	262.07 ± 6.39 e	271.47 ± 6.23 d
250 ppm	59.51 ± 2.93 cd	56.17 ± 1.93de	55.70 ± 2.48 de	39.87 ± 2.70 bcd	41.07 ± 0.59bc	42.33 ± 0.85 b	278.00 ± 4.23 d	291.47 ± 3.31 c	293.67 ± 5.67c
350 ppm	65.98 ± 3.03ab	60.67 ± 0.22c	56.19 ± 1.52de	41.80 ± 0.95 bc	41.47 ± 1.60bc	45.97 ± 2.24 a	291.93 ± 2.72c	302.13 ± 3.78 b	307.00 ± 1.97 b
450 ppm	69.13 ± 2.76 a	63.73 ± 1.79bc	63.57 ± 2.54bc	48.13 ± 0.91a	42.13 ± 1.51 b	49.20 ± 2.67 a	304.33 ± 3.29 b	319.33 ± 2.66a	320.67 ± 2.81 a

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Different letters indicate significant differences (P ≤ 0.05) between treatments using Duncans Multiple Range Test (DMRT) test. The results represented the mean and standard deviations (S.D.) of three replicates

Table 2.

Effect of seaweed extract and GA₃ on leaf morphology of Lagurus ovatus L.

	Leaf length (cm)			Flag leaf width (cm)			Leaf area (cm²)
Gibberellic acid dose	Seaweed extract (SWE) drench			Seaweed extract (SWE) drench			Seaweed extract (SWE) drench
	Untreated control	2 ml. L⁻¹	4 ml. L⁻¹	Untreated control	2 ml. L⁻¹	4 ml. L⁻¹	Untreated control	2 ml. L⁻¹	4 ml. L⁻¹
Untreated control	4.76 ± 0.05 h	5.16 ± 0.24 g	5.56 ± 0.03 ef	1.12 ± 0.01 fg	1.14 ± 0.04 defg	1.18 ± 0.02 bcde	3.75 ± 0.10 e	4.33 ± 0.27 de	4.62 ± 0.18 d
150 ppm	5.47 ± 0.02 f	5.77 ± 0.12 e	6.32 ± 0.18d	1.17 ± 0.01cdef	1.19 ± 0.02 bcde	1.21 ± 0.03 abc	4.41 ± 0.54 de	4.91 ± 0.40 cd	5.06 ± 0.10 bcd
250 ppm	6.45 ± 0.22d	6.91 ± 0.14c	7.37 ± 0.31b	1.19 ± 0.02 bcd	1.20 ± 0.04 abc	1.25 ± 0.06 a	5.37 ± 0.57 abc	5.63 ± 0.55 abc	5.71 ± 0.62 ab
350 ppm	6.46 ± 0.20 d	7.38 ± 0.21 b	7.46 ± 0.18 b	1.14 ± 0.03 efg	1.17 ± 0.03 cdef	1.23 ± 0.02 ab	5.52 ± 0.17 abc	5.79 ± 0.19 ab	5.84 ± 0.73 ab
450 ppm	7.28 ± 0.03 b	7.53 ± 0.15 b	7.89 ± 0.18 a	1.10 ± 0.03 g	1.15 ± 0.02 defg	1.22 ± 0.03 abc	5.73 ± 0.21 ab	5.86 ± 0.09 a	6.06 ± 0.85 a

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Leaf chlorophyll content

The findings indicate that both seaweed extract and GA₃ significantly influenced chlorophyll levels (Table 3). The highest chlorophyll content at all measured intervals (30, 60, and 90 days after transplanting) was observed with the conjoint application of 4 ml L⁻¹ seaweed extract plus 0 ppm GA₃, producing SPAD values of 30.97, 41.82, and 45.04, respectively.

Table 3.

Influence of seaweed extract and GA₃ on leaf chlorophyll content of Lagurus ovatus L.

	Chlorophyll content (SPAD value) 30 days of transplanting			Chlorophyll content (SPAD value) after 60 days of transplanting			Chlorophyll content (SPAD value) after 90 days of transplanting
Gibberellic acid doses	Seaweed extract (SWE) drench			Seaweed extract (SWE) drench			Seaweed extract (SWE) drench
	Untreated control	2 ml. L⁻¹	4 ml. L⁻¹	Untreated control	2 ml. L⁻¹	4 ml. L⁻¹	Untreated control	2 ml. L⁻¹	4 ml. L⁻¹
Untreated control	18.59 ± 1.85 e	27.29 ± 2.31 bcd	30.97 ± 2.27 a	23.36 ± 1.34 d	41.66 ± 1.59 a	41.82 ± 5.37 a	33.50 ± 1.42 h	42.08 ± 1.77 cde	45.04 ± 1.81 a
150 ppm	24.31 ± 2.08 d	25.27 ± 1.57 cd	27.79 ± 2.26abc	35.23 ± 1.74 c	35.99 ± 1.70 bc	37.60 ± 1.71 bc	39.76 ± 2.34 g	40.15 ± 1.05 fg	40.97 ± 2.56 efg
250 ppm	25.23 ± 0.84 cd	26.00 ± 2.20 bcd	28.28 ± 1.32 abc	36.49 ± 1.22 bc	36.65 ± 1.08 bc	38.13 ± 2.51 abc	40.30 ± 1.37 fg	40.91 ± 0.75 efg	41.35 ± 1.53 def
350 ppm	26.02 ± 1.50 bcd	27.03 ± 2.20 bcd	28.97 ± 2.01 ab	37.20 ± 0.82 bc	37.48 ± 2.57 bc	39.64 ± 1.76 ab	41.57 ± 1.72 cdef	42.01 ± 2.31 cde	42.53 ± 1.57 bcd
450 ppm	26.10 ± 1.93 bcd	28.10 ± 2.49 abc	29.00 ± 0.64 ab	38.26 ± 3.45 abc	38.47 ± 1.65 abc	40.00 ± 2.09 ab	42.67 ± 0.34 bcd	42.84 ± 1.20 bc	43.75 ± 0.59 ab

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Flowering traits

The different concentrations of seaweed extract and GA₃ also had a notable impact on flowering characteristics (Table 4, 5 and Fig. 1, 2). Application of 4 ml L⁻¹ seaweed extract + 450 ppm GA₃ reduced the number of days to first flower head initiation (95.00 days) and flowering (100.13 days) while increasing the inflorescences per plant to 188.27. However, the interaction effect of seaweed extract and GA₃ doses on the size of the flower heads was found non-significant. Of all the treatment combinations, 0 ml L⁻¹ seaweed extract + 450 ppm GA₃ resulted in the longest stem length (67.32 cm).

Table 4.

Effect of seaweed extract and GA₃ on flowering traits of Lagurus ovatus L.

	Days to first flower head initiation			Days to flowering			Number of inflorescences per plant
Gibberellic acid doses	Seaweed extract (SWE) drench			Seaweed extract (SWE) drench			Seaweed extract (SWE) drench
	Untreated control	2 ml. L⁻¹	4 ml. L⁻¹	Untreated control	2 ml. L⁻¹	4 ml. L⁻¹	Untreated control	2 ml. L⁻¹	4 ml. L⁻¹
Untreated control	105.50 ± 0.30 a	103.10 ± 0.90 b	101.80 ± 0.40 c	114.20 ± 0.53 a	111.80 ± 0.20 b	110.80 ± 0.40 b	110.67 ± 2.61 i	140.87 ± 1.10 g	160.80 ± 1.06 de
150 ppm	99.20 ± 0.20 d	98.90 ± 0.70 d	99.30 ± 0.10 d	108.13 ± 0.50 c	106.80 ± 0.60 cd	106.60 ± 1.93 d	134.47 ± 11.66 h	145.13 ± 3.72 g	163.07 ± 1.79 de
250 ppm	98.50 ± 0.50 de	97.50 ± 0.30 efg	97.00 ± 1.20 fg	105.20 ± 0.69 e	104.73 ± 1.29 e	104.60 ± 0.69 e	145.53 ± 4.47 g	158.73 ± 1.97 e	172.87 ± 4.11 c
350 ppm	97.60 ± 0.20ef	96.50 ± 0.30 fgh	96.20 ± 1.80 ghi	102.93 ± 0.76 fg	103.80 ± 0.20 ef	101.73 ± 0.50 gh	152.60 ± 2.55 f	166.33 ± 0.99 d	178.80 ± 1.51 bc
450 ppm	97.10 ± 0.10 fg	95.60 ± 0.40 hi	95.00 ± 0.40 i	102.33 ± 1.10gh	101.33 ± 0.23 hi	100.13 ± 0.31i	165.40 ± 2.82 d	180.00 ± 2.50 b	188.27 ± 1.75 a

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Table 5.

Effect of seaweed extract and GA₃ on flower quality and root biomass of Lagurus ovatus L.

	Length of flower head (cm)			Stem length (cm)			Fresh weight of root (g/plant)
Gibberellic acid doses	Seaweed extract (SWE) drench			Seaweed extract (SWE) drench			Seaweed extract (SWE) drench
	Untreated control	2 ml. L⁻¹	4 ml. L⁻¹	Untreated control	2 ml. L⁻¹	4 ml. L⁻¹	Untreated control	2 ml. L⁻¹	4 ml. L⁻¹
Untreated control	3.58 ± 0.04 h	3.70 ± 0.11 gh	3.76 ± 0.06 g	30.00 ± 1.18 f	35.35 ± 1.18 e	35.14 ± 0.88 e	10.07 ± 1.22 h	19.67 ± 2.05 de	20.67 ± 1.60 cd
150 ppm	3.96 ± 0.09 f	3.99 ± 0.08 f	4.08 ± 0.13 ef	51.46 ± 3.07 c	45.58 ± 3.08 d	45.03 ± 2.24 d	14.73 ± 1.75 g	19.73 ± 1.33 de	18.27 ± 0.50 def
250 ppm	4.05 ± 0.07 ef	4.11 ± 0.11 ef	4.22 ± 0.09 de	53.71 ± 4.17 c	52.75 ± 4.70 c	52.66 ± 3.45 c	19.53 ± 3.00 de	26.87 ± 4.11 a	23.13 ± 1.85 bc
350 ppm	4.34 ± 0.03 cd	4.43 ± 0.17 c	4.43 ± 0.18 c	60.13 ± 3.14 b	54.14 ± 4.07 c	53.32 ± 4.50 c	23.80 ± 2.60 b	15.20 ± 1.91 fg	24.00 ± 1.97 b
450 ppm	4.51 ± 0.08 bc	4.62 ± 0.05 ab	4.78 ± 0.05 a	67.32 ± 1.63 a	61.03 ± 1.18 b	60.42 ± 1.26 b	15.53 ± 1.42 fg	15.27 ± 0.81 fg	17.33 ± 1.67 efg

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Fig. 1 — Flowering of *Lagurus ovatus* L. influenced by various seaweed extract and gibberrellic acid doses

Fig. 2 — Flower head size of *Lagurus ovatus* L. influenced by various seaweed extract and gibberrellic acid doses

Root and shoot biomass

The characteristics of both roots and shoots were significantly influenced by the seaweed extract and GA₃ (Table 5, 6, 7). The best results for shoot fresh weight (108.85 g) and dry weight (52.07 g) were observed with the treatment combination of 4 ml L⁻¹ seaweed extract and 450 ppm GA₃. Additionally, the highest fresh root weight of 26.87 g was found with 2 ml L⁻¹ seaweed extract + 250 ppm GA₃. The treatment combination 4 ml L⁻¹ seaweed extract + 350 ppm GA₃ produced a dry root weight of 11.53 g and a root-to-shoot ratio of 0.24 on a dry weight basis. However, the interaction effects on the fresh root-to-shoot ratio and root length were found to be non-significant.

Table 6.

Effect of seaweed extract and GA₃ on dry matter production of Lagurus ovatus L.

	Fresh weight of shoot (g/plant)			Dry weight of root (g/plant)			Dry weight of shoot (g/plant)
Gibberellic acid doses	Seaweed extract (SWE) drench			Seaweed extract (SWE) drench			Seaweed extract (SWE) drench
	Untreated control	2 ml. L⁻¹	4 ml. L⁻¹	Untreated control	2 ml. L⁻¹	4 ml. L⁻¹	Untreated control	2 ml. L⁻¹	4 ml. L⁻¹
Untreated control	76.37 ± 2.90 f	99.20 ± 1.54 b	107.80 ± 1.60 a	4.33 ± 0.50 f	8.80 ± 0.20 bcde	9.87 ± 0.61 abcd	37.13 ± 2.89 h	45.00 ± 1.64 fg	48.33 ± 2.19 bcde
150 ppm	81.48 ± 2.53 e	88.93 ± 2.47 d	99.58 ± 2.25 b	7.20 ± 0.87 e	8.93 ± 0.12 bcde	9.00 ± 1.74 bcde	43.67 ± 1.10 g	46.10 ± 1.42 defg	48.20 ± 1.00 bcde
250 ppm	89.06 ± 3.28 d	90.99 ± 7.51 cd	101.74 ± 2.49 b	7.73 ± 1.36 de	10.27 ± 0.83 ab	10.07 ± 1.33 abc	45.40 ± 1.31 efg	48.13 ± 1.53 bcde	49.07 ± 1.72 abcd
350 ppm	93.87 ± 2.55 c	97.89 ± 3.07 b	106.82 ± 3.21 a	10.80 ± 1.59 ab	7.07 ± 1.51 e	11.53 ± 0.58 a	47.07 ± 2.34 cdef	49.60 ± 1.51 abc	50.07 ± 1.92 abc
450 ppm	99.31 ± 0.78 b	101.16 ± 1.35 b	108.85 ± 2.57 a	7.00 ± 2.12 e	7.93 ± 0.42 cde	9.47 ± 0.70 abcd	49.00 ± 1.31 bcd	51.00 ± 1.44 ab	52.07 ± 1.92 a

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Table 7.

Effect of seaweed extract and GA₃ on root: shoot ratio and root length of Lagurus ovatus L

	Root: shoot ratio on fresh weight basis			Root: shoot ratio on dry weight basis			Root length (cm)
Gibberellic acid doses	Seaweed extract (SWE) drench			Seaweed extract (SWE) drench			Seaweed extract (SWE) drench
	Untreated control	2 ml. L⁻¹	4 ml. L⁻¹	Untreated control	2 ml. L⁻¹	4 ml. L⁻¹	Untreated control	2 ml. L⁻¹	4 ml. L⁻¹
Untreated control	0.13 ± 0.02i	0.20 ± 0.03 defg	0.21 ± 0.03 def	0.12 ± 0.01 j	0.19 ± 0.01 efg	0.20 ± 0.02 cdef	9.91 ± 0.35 f	11.89 ± 0.08 bcd	12.44 ± 0.45 ab
150 ppm	0.18 ± 0.03fgh	0.22 ± 0.02 cde	0.23 ± 0.02bcd	0.14 ± 0.01 ij	0.20 ± 0.02 cde	0.22 ± 0.01abc	11.08 ± 0.22 e	12.24 ± 0.75 abcd	12.26 ± 0.24 abcd
250 ppm	0.22 ± 0.04 bcd	0.23 ± 0.02 bcd	0.25 ± 0.02abc	0.17 ± 0.02 gh	0.21 ± 0.02 cde	0.23 ± 0.01 ab	11.55 ± 0.15 de	12.30 ± 1.00 abcd	12.35 ± 0.32 abcd
350 ppm	0.25 ± 0.03 abc	0.26 ± 0.02 ab	0.28 ± 0.05 a	0.21 ± 0.01 bcd	0.22 ± 0.01 abc	0.24 ± 0.01 a	11.59 ± 0.08 cde	12.42 ± 0.75 abc	12.51 ± 0.31 ab
450 ppm	0.16 ± 0.02 hi	0.17 ± 0.01 gh	0.19 ± 0.02 efgh	0.16 ± 0.01 hi	0.18 ± 0.02 fgh	0.19 ± 0.01 defg	11.73 ± 0.12 bcde	12.45 ± 0.02 ab	12.92 ± 0.89 a

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Correlation analysis

The correlation plot provides an in-depth look at how different plant traits interact with each other, revealing both positive and negative relationships (Fig. 3). Understanding these relationships allows to make more informed decisions about which traits to prioritize for improving overall plant performance. The plant height exhibits strong positive correlations with plant spread (r = 0.56, p = 0.74), number of leaves (r = 0.74, p = 0.74), number of inflorescence (r = 0.62, p = 0.05) and dry weight of shoot (r = 0.65, p = 0.01). Length of flower head was found to be positively correlated with plant spread (r = 0.75, p = 0.01) and stem length (r = 0.63, p = 0.05). Stem length was also positively correlated with plant spread (r = 0.60, p = 0.05), number of leaves (r = 0.75, p = 0.01) and fresh weight of shoot (r = 0.54, p = 0.05). This means that plants with greater height tend to increase plant spread, greater number of leaves and inflorescences. As plant height increases, so does the number of leaves and inflorescences, which are also indicators of overall plant vigor and health.

Fig. 3 — Pearson’s correlation matrix of various growth and flowering parameters of Lagurus ovatus L. in response to seaweed extract drench and foliar GA₃ applications. PLH- plant height; PS-plant spread; NOL-number of leaves; FLL-flag leaf length; FLW- flag leaf width; LA-leaf area;30-chorophyll content (SPAD value) at 30 days after transplanting; 60-chorophyll content (SPAD value) at 60 days after transplanting; 90-chorophyll content (SPAD value) at 90 days after transplanting; FHI-days to first flower head initiation; DTF- days to flowering; NOI-number of inflorescence; LFH-length of flower head;; SL-stem length; FWR- fresh weight of root; FWS-fresh weight of shoot; DWR- dry weight of root; DWS-dry weight of shoot; RSF-root: shoot ratio on fresh basis; RSD- root: shoot ratio on dry basis; RL-root length

On the other hand, traits associated with early flowering, such as the first flower head initiation and days to flowering, show strong negative correlations with traits like plant height, plant spread, number of leaves, chlorophyll content, number of inflorescences and root length. This suggests that plants that flower earlier tend to have lower plant height, lower plant spread, fewer leaves and lower chlorophyll content, which might reflect a trade-off where energy is allocated more towards reproductive processes at the expense of vegetative growth.

Yield attributes parameter i.e. number of inflorescences shows a significant positive correlation with parameters viz., stem length (r = 0.63, p = 0.05), dry weight of root (r = 0.59, p = 0.05) and root: shoot ratio on dry weight basis (r = 0.65, p = 0.01).

Principal component analysis

The best treatment for enhancing growth, flowering and yield of lagurus was evaluated using principal component analysis, wherein a significant relationship between growth and flowering attributes due to different treatments viz., seaweed extract drenches and GA₃ foliar dose applications, was analyzed.

Growth and flowering parameters from 15 treatment combinations were subjected to PCA for analysis of compositional variations. The correlation coefficients of different variables in PCA were evaluated by the cosine of the angle between their vectors [28].

Principal component analysis indicated that three components (PC1, PC2 and PC3) with eigen value more than one accounted for about 90.11% of the total variation among 21 characters of Lagurus ovatus. The principal component PC1, PC2 and PC3 contributed about 64.58%, 17.08% and 8.45% respectively, to the total variation (Table 8,9). The association among the different variables in PC-1 and PC-2 with factor loadings is presented in Fig. 4. Biplot depicts the variation contribution of parameter with respect to first two principal components. X-axis represents PC-1 and Y-axis represents PC-2. From the biplot it can be seen that highest amount of contribution among the traits is observed in plant height, stem length and length of flower head.

Table 8.

Eigen values and percentage of variance corresponding to each principal component

	Eigen value	Percentage of variance	Cumulative percentage of variance
Comp 1	13.56	64.58	64.58
Comp 2	3.59	17.08	81.66
Comp 3	1.77	8.45	90.11
Comp 4	0.79	3.77	93.88
Comp 5	0.44	2.09	95.97
Comp 6	0.36	1.70	97.68
Comp 7	0.18	0.87	98.55
Comp 8	0.11	0.51	99.07
Comp 9	0.10	0.47	99.54
Comp 10	0.04	0.20	99.74
Comp 11	0.03	0.14	99.88
Comp 12	0.02	0.07	99.96
Comp 13	0.01	0.03	99.99
Comp 14	0.00	0.01	100.00

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Table 9.

Contribution of each parameter towards variance of principal components

	PC1	PC2	PC3	PC4	PC5
PLH	3.71	1.04	2.95	6.64	9.53
PS	4.40	1.12	6.64	4.96	4.13
NoL	6.89	4.54	0.94	5.65	7.87
FLL	5.77	3.63	0.93	4.80	1.27
FLW	1.81	5.97	9.14	3.17	8.03
LA	6.23	2.51	2.09	1.40	9.05
30	5.02	5.01	6.32	2.49	2.17
60	4.40	3.97	7.14	8.52	4.21
90	5.09	1.50	10.27	5.68	2.83
FHI	5.78	3.60	2.97	1.24	2.08
DTF	5.58	5.31	2.23	4.17	2.47
NOI	6.80	3.85	1.09	5.31	1.48
LFH	5.05	7.79	0.03	1.02	1.27
SL	3.73	1.10	1.47	6.75	6.31
FWR	2.02	9.07	10.17	1.57	1.28
FWS	4.93	2.25	10.17	2.29	2.49
DWR	3.59	8.83	2.79	6.01	1.40
DWS	7.05	1.66	1.28	3.80	1.66
RSF	2.42	7.07	15.67	3.16	8.13
RSD	3.85	8.05	4.61	6.76	1.67
RL	5.87	2.36	1.09	2.82	3.43

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Fig. 4 — PCA biplot representing different treatments of seaweed extract and GA3 along with various parameters of Lagurus ovatus. PLH- plant height; PS-plant spread; NOL-number of leaves; FLL-flag leaf length; FLW- flag leaf width; LA-leaf area;30-chorophyll content (SPAD value) at 30 days after transplanting; 60-chorophyll content (SPAD value) at 60 days after transplanting; 90-chorophyll content (SPAD value) at 90 days after transplanting; FHI-days to first flower head initiation; DTF- days to flowering; NOI-number of inflorescence; LFH-length of flower head;; SL-stem length; FWR- fresh weight of root; FWS-fresh weight of shoot; DWR- dry weight of root; DWS-dry weight of shoot; RSF-root: shoot ratio on fresh basis; RSD- root: shoot ratio on dry basis; RL-root length

Almost all the variables are positively contributing. The analysis revealed that the treatment combinations viz., 2 ml L⁻¹ seaweed extract + 250 ppm GA₃, 4 ml L⁻¹seaweed extract + 150 ppm GA₃, 4 ml L⁻¹ seaweed extract + 250 ppm GA₃ and 4 ml L⁻¹ seaweed extract + 350 ppm GA₃ were located on the positive side of PC1 in the upper right quadrant resulting in plants with higher flag leaf width, root shoot ratio on fresh weight and dry weight basis, root length, fresh weight and dry weight of shoot and chlorophyll content at 60 and 90 days after transplanting. Parameters like days to first flower head initiation and days to flowering are located in the upper left quadrant of the biplot.