Seedling Vigor Research Articles

Correlation of Germination, Seedling Vigour Indices and Enzyme Activities in Response to Liquid Organic Kunapajala to Predict Field Emergence in Late Sown Wheat

A laboratory experiment was conducted to correlate the germination test with seed vigour parameters and enzyme activities to predict seedling vigour and planting value on late sown wheat variety UP-2526. The experiment was conducted at GBPUA and T, Pantnagar during rabi season of 2020-2. The experiment consisted of five treatments viz; no priming (control), hydropriming, 10%, 25% and 50% kunapajala priming for 16 hrs. Results revealed that germination percentage was positively and significantly correlated with speed of germination (0.914*), seedling vigour index-II (0.890*), α-amylase activity at 12 and 16 hrs of priming (0.942* and 0.947*, respectively), seed reserve mobilization efficiency on 4th day (0.954*) after incubation and imbibition rate after 16 and 24 hrs of soaking duration (0.933* and 0.894*, respectively). Heat stress both low and high temperature are major reason of declining yield in wheat when sown delayed. Prediction of seedling vigour and field emergence of seed before sowing is prime important for assured yield in late sown condition.

Effect of Stimulating Maize Seeds with Potassium Nitrate and Licorice Extract on the Seed Viability and Vigor

Germination and field emergence are delayed and their duration is prolonged due to the declining soil temperature during the spring season, which is reflected in the subsequent stages of crop growth, therefore, this study aimed to improve germination. Under a wide range of environmental conditions, a laboratory factorial experiment was carried out to study the effect of seed stimulation with potassium nitrate (distilled water only (0), 2, 4, and 6 mg L-1) and with an aqueous extract of licorice roots (distilled water only (0), 3, 6, and 9 g L-1) on the seed viability and vigor. The laboratory experiment was carried out according to the Completely Randomized Design (CRD) with four repetitions. The results showed the superiority of the interaction treatment between the two concentrations 6 gm L-1 and 6 mg L-1 for each of licorice root extract and potassium nitrate by giving the highest average of the final germination 99%, the seedling vigor index reached 3846, the germination percentage at accelerating age test of 75%, and the germination percentage at the cold test of 76%. We can conclude that there was a response to soaking the seeds in licorice root extract at specific concentrations, with a clear response to potassium nitrate, and the response could be better when soaking in potassium nitrate at concentrations higher than 6 mg L-1. We also recommend that the soaking duration in any of the two factors is 18 hours to improve germination under a wide range of environmental conditions.

Complexity of SMAX1 signaling during seedling establishment.

Karrikins (KARs) are small butenolide compounds identified in the smoke of burning vegetation. Along with the stimulating effects on seed germination, KARs also regulate seedling vigor and adaptive behaviors, such as seedling morphogenesis, root hair development, and stress acclimation. The pivotal KAR signaling repressor, SUPPRESSOR OF MAX2 1 (SMAX1), plays central roles in these developmental and morphogenic processes through an extensive signaling network that governs seedling responses to endogenous and environmental cues. Here, we summarize the versatile roles of SMAX1 reported in recent years and discuss how SMAX1 integrates multiple growth hormone signals into optimizing seedling establishment. We also discuss the evolutionary relevance of the SMAX1-mediated signaling pathways during the colonization of aqueous plants to terrestrial environments.

SALINITY STRESS AS AN ABIOTIC FACTOR AT GERMINATION STAGE ON DRY BEAN (Phaseolus vulgaris L.) CULTIVARS

The study focused on germination parameters as the most critical stage of plant development in dry bean cultivars under different salt treatment. For two used cultivars (Akman-98, Karaman-2016) the data on germination percentage, mean germination time, seedling shoot length, seedling root length, seedling length and seedling vigor indexes were reached under the different salinity levels of irrigation water (0 mM, 25 mM, 50 mM, 100 mM, 150 mM, and 200 mM of NaCl) in Petri plates. The data indicates that these parameters could be used as screening the dry bean cultivars against salt stress levels. This study was carried out in a Completely Randomized Design (CRD) with a total of 12 treatments (6 salinity x 2 cultivars) for the germination and seedling data each comprising of three replicates. The results demonstrated that; i) From the overall observation of the germination characters, at 100 mM and over salt treatments showed decreasing in the germination percentage, the seedling length and the seedling vigor index in the mean of the cultivars, ii) Significantly decreasing in the seedling shoot length were observed in the mean of the cultivars at just after 25 mM and gradually at all salt concentrations, iii) Although the root length showed increasing in 25 and 50 mM treatments than the control plants, a sudden decrease occurred after 100 mM salt treatment in the mean of the cultivars and in each cultivars separately, iv) The mean germination time were sharply in increasing starting with 25 mM treatment in the mean of the cultivars, v) Except the seedling shoot length, in the mean of all the salt treatments between the cultivars did not show statistically differences in the calculated parameters, vi) Any correlation was found between the salt concentrations and the cultivars.

Standardization of Nipping Technique for Enhancement of Seed Yield and Quality in Sunn Hemp

A field experiment entitled “standardization of nipping technique for enhancement of seed yield and quality in sunn hemp” was conducted during Kharif 2019-20 and 2020-21 at Seed Production Block, NSP, Seed Unit, UAS, Raichur. The experiment was laid out in a randomized complete block design with fifteen treatments including nipping and foliar spray of cycocel and their combinations in three replications. The results emanated from the experiment recorded maximum plant height (cm), early 50 per cent flowering and maturity in T1 (no nipping). Whereas, nipping at 30 and 40 DAS and foliar spray of cycocel at 50 DAS (T15) recorded maximum number of branches per plant, chlorophyll content (SPAD Values), leaf area (cm2), number of pods per plant, seed yield per plant, seed yield (q ha-1), seed germination (%), total seedling length (cm), seedling dry weight (mg) and seedling vigour index I and II. While the nipping at 30 DAS and foliar spray of cycocel @ 1000 ppm at 40 DAS (T12) is a better option in terms of obtaining higher net returns and B:C ratio in sunn hemp. Whereas, maximum cost of cultivation was found in nipping at 30, 40 DAS and 50 DAS (T8).

Effects of Seed Invigoration Treatments with Bio-priming on Germination, Vigour and Seedling Growth in Black Gram (Vigna mungo L.)

A study had been conducted in black gram to observe the effect of different seed invigoration treatments with bio-priming for seed germination, seedling growing and vigour. The variety of black gram i.e., Uttara, was selected and seed had been treated with control (T1); Seeds soaked in distilled water/ hydropriming (T2); Rhizobium leguminosarum 10% (T3); Rhizobium leguminosarum 15% (T4); Rhizobium leguminosarum 20% (T5); Rhizobium leguminosarum 25% (T6); Rhizobium leguminosarum 30% (T7) respectively. Treated seeds were grown in different glass plate and patri plate at Seed Testing Laboratory, Bidhan Chandra Krishi Viswavidyalaya, Mohanpur, Nadia, West Bengal, India. Seed invigoration with Rhizobium leguminosarum at 20% followed by T4 was found very effective for seed germination with vigorous seedlings. Higher seed germination percentage (82.60), shoot length (17.89 cm), root length (12.99 cm), seedling fresh weight (1.87 g), seedling dry weight (0.19 g), seedling vigour index I (2393.62) and seedling vigour index II (15.96) results were observed for the seed bioprimed with Rhizobium leguminosarum at 20%. Seed treatment with Rhizobium leguminosarum at 20% recorded better performance than rest the treatments for all characters observed. The present investigation clearly depicted that the germination, vigour and seedling growth revalidated seed lots can be improved by pre-sowing and invigoration treatments.

Registration of eight germplasm lines of upland cotton (Gossypium hirsutum L.) resistant to reniform nematodes (Rotylenchulus reniformis) with elite agronomic performance

AbstractCotton (Gossypium hirsutum L.) germplasm lines BARBREN‐713‐8 (Reg. no. GP‐1138, PI 701080), BARBREN‐713‐11 (Reg. no. GP‐1131, PI 701073), BARBREN‐713‐13 (Reg. no. GP‐1132, PI 701074), BARBREN‐713‐25 (Reg. no. GP‐1133, PI 701075), BARBREN‐713‐32 (Reg. no. GP‐1134, PI 701076), BARBREN‐713‐33 (Reg. no. GP‐1135, PI 701077), BARBREN‐713‐41 (Reg. no. GP‐1136, PI 701078), and BARBREN‐713‐48 (Reg. no. GP‐1137, PI 701079) were developed and released by the USDA‐ARS, Texas A&M AgriLife Research, and Cotton Incorporated in 2014. The objective of the release was to provide breeders with agronomically elite germplasm that is resistant to reniform nematode (Rotylenchulus reniformis). Four lines (BARBREN‐713‐8, ‐32, ‐33, and ‐48) also have simple sequence repeat (SSR) DNA markers for the Mi‐1 or Mi‐2 gene for resistance to root‐knot nematode [Meloidogyne incognita (Kolfoid & White) Chitwood]. The lines have excellent seedling vigor in fields infested with both nematodes and fungal root‐rot pathogens. Resistance to reniform nematode was transferred from G. barbadense GB713 (PI 608139) and is associated primarily with the Ren2GB713 gene on chromosome 21. This gene could be detected with the codominant SSR marker BNL3279_105 or the single nucleotide polymorphism marker GI‐187401. In controlled environment assays, these lines reported here suppressed numbers of reniform nematode eggs by 74–92% compared with ‘FiberMax FM966’. The lines outyielded and had fiber quality equal to or greater than several commercial cultivars.

Genome-wide association studies in rice germplasm reveal significant genomic regions for root and yield-related traits under aerobic and irrigated conditions.

The development of nutrient-use efficient rice lines is a priority amidst the changing climate and depleting resources viz., water, land, and labor for achieving sustainability in rice cultivation. Along with the traditional transplanted irrigated system of cultivation, the dry direct-seeded aerobic system is gaining ground nationwide. The root-related traits play a crucial role in nutrient acquisition, adaptation and need to be concentrated along with the yield-attributing traits. We phenotyped an association panel of 118 rice lines for seedling vigour index (SVI) traits at 14 and 21 days after sowing (DAS), root-related traits at panicle initiation (PI) stage in polythene bags under controlled aerobic condition, yield and yield-related traits under the irrigated condition at ICAR-IIRR, Hyderabad, Telangana; irrigated and aerobic conditions at ARS, Dhadesugur, Raichur, Karnataka. The panel was genotyped using simple sequence repeats (SSR) markers and genome-wide association studies were conducted for identifying marker-trait associations (MTAs). Significant correlations were recorded for root length, root dry weight with SVI, root volume at the PI stage, number of productive tillers per plant, spikelet fertility, the total number of grains per panicle with grain yield per plant under irrigated conditions, and the total number of grains per panicle with grain yield per plant under aerobic condition. The panel was divided into three sub-groups (K = 3) and correlated with the principal component analysis. The maximum number of MTAs were found on chromosomes 2, 3, and 12 with considerable phenotypic variability. Consistent MTAs were recorded for SVI traits at 14 and 21 DAS (RM25310, RM80, RM22961, RM1385), yield traits under irrigated conditions (RM2584, RM5179, RM410, RM20698, RM14753) across years at ICAR-IIRR, grain yield per plant (RM22961, RM1146) under the aerobic condition, grain yield per plant at irrigated ICAR-IIRR and SVI (RM5501), root traits at PI stage (RM2584, RM80, RM410, RM1146, RM18472). Functionally relevant genes near the MTAs through in-silico expression analysis in root and panicle tissues viz., HBF2 bZIP transcription factor, WD40 repeat-like domain, OsPILS6a auxin efflux carrier, WRKY108, OsSCP42, OsMADS80, nodulin-like domain-containing protein, amino acid transporter using various rice expression databases were identified. The identified MTAs and rice lines having high SVI traits (Langphou, TI-128, Mouli, TI-124, JBB-631-1), high yield under aerobic (Phouren, NPK-43, JBB-684, Ratnamudi, TI-112), irrigated conditions (KR-209, KR-262, Phouren, Keibi-Phou, TI-17), robust root traits like root length (MoirangPhou-Angouba, Wangoo-Phou, JBB-661, Dissi, NPK-45), root volume (Ratnachudi, KJ-221, Mow, Heimang-Phou, PUP-229) can be further employed in breeding programs for the targeted environments aimed at improving seedling vigour, yield-related traits under irrigated condition, aerobic condition as adaptability to water-saving technology.

Synthesis and characterization of nickel oxide nanoparticles and their effect on seed germination of Vigna radiata

Nickel oxide (NiO) nanoparticles, using chemical reduction method, have been synthesized by the reaction of nickel chloride hexahydrate (NiCl2.6H2O) salt with triethylamine (Et3N) as a reducing agent at 700C and thermal decomposition of the precursor nickel hydroxide Ni(OH)2 nanoparticles from 3000C to 6000C at an increment of 1000C. The product was characterized by using X-Ray diffraction (sharp picks at 280,380,600), Scanning electron microscopy (average particle ranges between 1-100), UV-Vis spectrophotometer (absorption band at 320-350 nm), Fourier transform infrared spectroscopy (strong band at 750 cm-1), Energy dispersive X- ray spectroscopy (% weight of NiONPs is 12.73) analysis etc. The synthesized nanoparticles and nickel salt have been investigated for biophysical parameters like germination percentage, radical length (RL), Plumule length (PL) and seedling vigor index (SVI) on Vigna seed germination. The seeds treated with lower concentration show enhancement in germination% and SVI.

Genotypic variation in germination rate, seedling vigor, and seed phenotype of Kentucky bluegrass cultivars

AbstractKentucky bluegrass (Poa pratensis L.) is the most widely used cool‐season turfgrass for athletic fields, but its seeds germinate slowly. The objective was to determine the germination rate, seedling vigor, and seed phenotype of Kentucky bluegrass cultivars. Germination and seedling vigor tests were conducted using a seed incubator set at alternating 25/15°C (day/night) temperatures and an 8 h day−1 photoperiod. Twenty‐one cultivars were tested using two seed lots for each. Germination was most rapid among the experimental genotype PST‐T15‐44 and the commercial cultivar "After Midnight, as they took the minimum days to reach 50% germination in only 7.9–8.0 or 8.8 days, respectively. Cultivars Tirem and Volt required >12 days in both lots to reach 50% germination (12.0–13.7 days). There was a difference of 5–6 days in 50% germination between cultivars. Seedling vigor was also measured but few differences between cultivars were noted. Data on seed phenotype including seed length, width, area, circularity, and thousand seed weights (TSW) all varied by cultivar. ‘‘After Midnight’’ had the longest seeds (3.065 mm). ‘‘Moonlight SLT’’ seeds were the shortest in length (2.366 mm), narrowest in width (0.717 mm), and smallest in area (1.328 cm2). Across all cultivars, seed length and circularity were correlated with germination rate (r = 0.62, p = 0.0025; r = −0.53, p = 0.0141). Seed phenotyping could be an important tool in breeding for improved germination rate. By identifying and using rapidly germinating Kentucky bluegrass cultivars, it may be possible to establish turf more rapidly.

Influence of Fungicidal Seed Treatments against Pathogen Complex Found on Paddy Seed and Their Effects on Seedling Germination, Growth, and Plant Vigor

A paddy (Oryza sativa) seed treatment study was conducted by the Plant Pathology Department, GRDB, RRS, Burma to evaluate the effectiveness of eight fungicides [Amistar Xtra 28SC, Saaf 75 WP, Glory 75WG, Tridium 70WG, Antracol 70WP, Rodazim 50 SC, Carbendazim 50SC and Manzate Pro Stick TM], at varying rates, along with a healthy check and untreated control, on germination and seedling vigour of paddy, and identifying suitable fungicides to be used as pre-sowing seed treatment. Trials were carried out under laboratory, potted and field conditions. A completely randomized block (CRD) was used for the laboratory and pot trials and randomized complete block design (RCBD) was used for the field trials, with three replicates. These trials were conducted in both rice growing seasons (Spring and Autumn) in Guyana during 2020 and 2021. Dry seed examination and blotter test unearthed the presence of four dominant pathogenic genera (Curvularia lunata, Bipolaris oryzae, Pyricularia oryzae and Aspergillus spp). from the paddy seeds before being treated and in the untreated control. The results of the germination test during 2020 showed variability among treatments, percentage germination ranged from 61% in seeds treated with Amistar Xtra 28 SC 3.7ml/L to 91% in seeds treated with Saaf 75 WP 5.6g/L. While in 2021 the percentage germination ranged from 79% in seeds treated with Tridium 70 WG 4.3g/L to 95% in seed treated with Saaf 75 WP 5.6g/L. Results from the in vitro studies showed seeds treated with Saaf (3.1g/L and 5.6g/L), Manzate Pro Stick TM (3.7 g/L), Glory at 12.4g/L, Rodazim (at 3.7ml/L) and the healthy control produced seedlings with taller shoots, longer roots and ultimately the higher seedling vigour at 14 and 21 days after treatment as compared to other treatments and the untreated control. Similarly, under potted condition seed treated with Rodazim (1.2ml/L and 3.7ml/L), Saaf (5.6g/L) and Glory (7.4g/L and 12.4g/L) demonstrated SVI compared to the other treatments and the untreated control. Further, under field condition the three fungicides viz. Rodazim, Manzate and Glory found to be promising in previous trials were selected and evaluated against an untreated control. Data collected revealed no significant difference among any of the treatments for grain yield, number of tillers/m2, plant height, the weight per 1000 grain nor the number of unfilled grains per panicle. However, treatment with Manzate Pro Stick TM (3.7 g/L) produced the largest number of filled grains as compared to the other treatment and control. It is therefore recommended that farmers should employ seed treatment prior to sowing if do not have clean, certified disease free seeds and use the paddy seed treatment [Saaf (5.6g/L), Manzate Pro Stick TM (3.7 g/L), Glory at (12.4g/L), Rodazim (3.7ml/L)] as a method of controlling seed borne pathogens, enhancing germination, seedling vigour and ultimately improving productivity.

Integrated management of seed borne pathogenic fungi of different varieties of cotton (Gossypium hirsutum L.)

Single and combined doses of fungicides, plant extracts, and antagonists were used to control of nine cotton pathogens through a pot experiment. A total of 19 treatments, and controls with or without inocula of the pathogen were tested. Out of 19 treatments, T1 (Tilt) and T11 (Tilt + Azadirachta indica + Trichoderma viride) exhibited maximum seed germination and seedling vigor index against Aspergillus flavus, A. niger, Curvularia lunata, Fusarium nivale, Mucor sp. and A. tamarii, Colletotrichum gloeosporioides, F. moniliforme, Rhizoctonia solani respectively. T5 (T. viride), T10 (Tilt + Psidium guajava + T. viride) and T14 (Tilt + A. indica) showed promising germination percentage and seedling vigor index against A. flavus, R. solani and A. tamarii, F. nivale and A. niger, C. gloeosporioides, C. lunata, F. moniliforme, Mucor sp. respectively. Among all the treatments, the combined use of Tilt + A. indica + T. viride showed the best results for reducing the growth of the test pathogens and increasing the germination percentage of seeds. J. Asiat. Soc. Bangladesh, Sci. 49(1): 27-42, June 2023

Seedlings germination aspects of the Carapa guianensis and its ecological conservation for the Amazonian peoples

Anthropic action with intense fruit exploitation for medicinal purposes has caused genetic erosion of ‘andirobeira’ (Carapa guianensis Aublet.), associated with unusual phasic germination, generating the need for research to obtain vigorous seedlings. Therefore, the objective of this work was to evaluate different substrates on seedling germination and phasic development, contributing to the conservation of this important, very threatened, species. The experimental design used was randomized blocks, with three treatments: Yellow Latosol (LA), Quartzarenic Neosol (NQ) and Haplic Gleysol (GH), and three replications of 40 plants each. The following characteristics were evaluated: seedling height (AP), root length (CR), stem diameter (DC), and leaf area (AF), along with dry weights from seeds (PSS), roots (PSR), stems (PSC) and leaves (PSF), in addition to the total dry weight (PST), relative growth rate (TCR), and net assimilation rate (TAL). The conclusions were that the days after emergence do not influence the TCR and TAL, but the substrate characteristics affect seedling development. The substrate LA, relative to NQ and GH, should be chosen to obtain seedlings with better development, resulting in superior seedlings. Indeed, the development of seedlings in NQ and GH substrates indicates that their use in the recovery of degraded areas is possible, and the andirobeira presents phasic seedling development, which must be known for effective ecological conservation. Damage to the cotyledons must be avoided to supply the period in which the seedling returns to the heterotrophic state, otherwise the subsequent development of the plant may be compromised.

Effect of biosynthesized ZnO nanoparticles on the seed germination and seedling vigour index of sesame (Sesamum indicum L.)

Sesame is an important oilseed crop, and the establishment of sesame in the field is critical because of its poor seed quality. One of the opportunities to improve seed germination and seedling establishment is the use ofnanoparticles. Therefore, the studywas conducted toevaluate the effects of biosynthesized zinc oxide nanoparticles (ZnO NPs) from a medicinal weed, Tridex daisy (Tridex procumbens L.) on seed germination, and seedling vigour ofsesame (Sesamum indicum L.). Zinc oxide nanoparticles were synthesized through the green synthesis method by using zinc acetate as precursor and Tridax procumbens leaf extract as reductant. The synthesized product has been characterized byParticle Size Analyzer (PSA), UV-visible spectroscopy,scanning electron microscope (SEM), and transmission electron microscope (TEM). Then, the sesame seeds were treated with ZnO NPs, and seed germination and seedling vigour were quantified. The result indicated that the size of the ZnO NPs was 94 nm, assessed through a particle size analyzer. The UV-visible spectrum of synthesized colloidal ZnO NPs had themaximum absorbance peak at 298 nm. The SEM and TEM analysis indicates that ZnO NPs are spherical in shape. EDX confirms the purest form of Zn in ZnO NPs. The ZnO improved the seed germination and root growth ofsesame compared to untreated control. Thus, it is evident that seed treatment with ZnO NPs can be a potential approach to improve the seedling establishment of sesame.

Bioregulators promote emergence of african mahogany seedlings?

Using bioregulators has proven to be effective for the vigor of seedlings of several forest species, besides reducing the unevenness of emergence and development. In view of the above, the present study establishes the following research problem: can Acadian® and Stimulate® applied to African mahogany seeds at different doses be effective in promoting emergence and vigor of seedlings? The experimental design used was completely randomized, in a 2 x 5 factorial scheme, corresponding to two hormones (Stimulate® and Acadian®) and five doses (0.0; 0.05, 0.1; 0.2 and 0.4 ml L-1), with four replicates, each with 25 seeds. Acadian® at the dose of maximum technical efficiency of 0.17 ml L-1 is efficient in reducing emergence time and increasing the percentage of seedlings with two expanded leaves, promoting better uniformity of seedlings and higher yield in the use of African mahogany propagating material. Stimulate® does not promote gains in the percentage of emergence and inhibits the vigor of African mahogany seedlings.

The Allelopathic Effect of Root Exudates of Mungbean and Maize Plants Affected by Metabiolic, Fertilizer and Mechanical Stress Factors on some Indicators of Germination of Cowpea Seeds

Allelopathic compounds are secondary metabolites created biologically by plants and microbes from the metabolism of carbohydrate, fats and amino acids. The process of their synthesis is affected by the type of plants, the path of its photosynthesis, its nutrition and various stress processes. When released to the rhizosphere, its effect begins on soil organisms, as it is considered a from of communication between plants. Which affects biological and agricultural systemis. A randomized complete block design (RCBD) was adopted with a factorial experiment with three factors and three replication. The experiment was carried out in one of the fields of Al-Taliáh sub-district/Babylon governorate to find out the allelopathic effect of root exudates of mungbean (Vigna radiata L.) and maize (Zea mays L.) affected by metabolic factors, fertilizer and mechanical stress on some germination indicators of cowpea seeds (Vigna unguiculata L.). The allelopathic effects of root exudates varied on the studied traits, as root exudates of mungbean caused a significant decrease in radicle length (RL), seedlings length (SL), and vigor index (VI) of cowpea plants for treatments affected by chemical fertilizer and not affected by mechanical stress, and a significant decrease in radicle length for treatments affected by mechanical stress and organic fertilizer, and a significant decrease in seedlings length and vigor index for treatments affected by mechanical stress and biofertilizer.

Evaluation of different fungicides against rice seedling rot incited by Sclerotium rolfsii Sacc.

Seedling rot disease in rice incited by Sclerotium rolfsii Sacc. in the rice nursery raised during December to January for summer rice cultivation is an emerging threat to rice cultivation in South Gujarat. In the present climate change scenario, rice crop is facing the challenges of new diseases which were otherwise not touching the economical threshold. Eight fungicides were evaluated under in vitro condition. Tebuconazole 50% + trifloxystrobin 25%, mancozeb 63%+ carbendazim 12%, azoxystrobin 18.2%+difenoconazole 11.4%SC, azoxystrobin 11.5% + mancozeb 30.0% and thiram 75 WS gave complete mycelial growth inhibition at 50 ppm concentration. Whereas azoxystrobin 23SC and tebuconazole 2% DS showed good mycelial growth inhibition ability with 83.30 and 90.74%, respectively. Most effective fungicides under in vitro were evaluated against seedling rot disease under field conditions during 2018 to 2020. Seed treatment with fungicides revealed that rice seeds treated with azoxystrobin 23SC @ 1ml /kg seed and soil application with Trichoderma harzianum (2×106 cfu/g) @ 1 g/m2 which was at par with seeds treated with azoxystrobin 23SC @ 1ml/kg seeds and azoxystrobin 18.2% + difenoconazole 11.4 %SC @ 1ml/kg seeds effectively managed seedling rot disease and given highest plant population with minimum seedling mortality, improved shoot and root length and good seedling vigor index.

Rethinking Iconic Species Reforestation in West Africa: Seed Shape Harnessing Is Strategic for Enhanced Germination and Vigorous Growth in Khaya senegalensis and Parkia biglobosa

Seed size is a critical factor that can impact the regeneration process of plant populations. The objective of this study is to identify optimal seeds for the cultivation of two overexploited native forest species in Côte d’Ivoire, namely Khaya senegalensis (Desr.) A.Juss., 1830 and Parkia biglobosa (Jacq.) R.BR. ex G. Don, 1830. A total of 1080 seeds per species were evaluated for germination and seedling vigour in two distinct environments (dry and humid) in Côte d’Ivoire. The results demonstrated that, for Khaya senegalensis, larger seeds exhibited higher germination rates, whereas for Parkia biglobosa, smaller and medium-sized seeds showed better germination performance. However, regardless of species and study site, larger seeds consistently produced more vigorous seedlings. In this case, pretreatment tests on large seeds of Parkia biglobosa can potentially enhance their germination performance. Large seeds, ranging from 0.25–0.37 g in Khaya senegalensis and 0.2–0.32 g in Parkia biglobosa, appear to be the most suitable and best candidates for high-quality, high-performance seeds to optimise the cultivation of these species in Côte d’Ivoire. Distributing such seeds to farmers can contribute to the success of reforestation and agroforestry programs involving these target species in Côte d’Ivoire. These findings contribute to the sustainable management of the target species and can serve as a basis for restructuring forest regeneration policies in Côte d’Ivoire.

Effect of different methods of depulping on viability, germination, seedling vigour and its economic analysis in neem (Azadirachta indica A. Juss.)

The present study was conducted to determine the effect of different methods of de-pulping on viability, germination, seedling vigour and the economics of post-harvest seed management in terms of its quality for seedling production and industrial application. The physiologically matured ripe yellowish green-coloured fruits of neem were harvested manually, and the seeds were extracted by manual and mechanical de-pulping. In each method, skin weight (kg), pulp weight (kg), man-hour requirements, cost of de-pulping (Rs/kg), seed recovery (%) and moisture content (%) were calculated. After de-pulping, seeds were manually washed with water and time taken for washing the de-pulped seeds was also calculated. After that seeds were dried in threshing yard and moisture content of seed was calculated. Dried seeds were processed using cleaner cum grader in mechanical method and sieves in manual method. In both the methods, fruit to seed recovery (%) were calculated. The effect of manual and mechanical seed extraction on viability (%), germination (%) and seedling vigour was analyzed. Results revealed that mechanical method of de-pulping (45.5kg) exhibited an additional wet seed weight of 1.5kg compared to manual method (44kg). The seed recovery from one ton of neem fruits was 170.5 kg in manual de-pulping and 164 kg in mechanical de-pulping. The processing cost of one kg of neem seed was Rs.9.03 for manual de-pulping and Rs.2.49 for mechanical de-pulping. Among the two methods of seed extraction, even though there was not much variation in seed recovery, germination and seedling vigour, mechanical method had the advantage of 160 minutes less time duration for extraction and minimal processing cost per kg of seed extraction with higher seedling vigour index.

Molecular Mechanisms in Understanding Anoxia Tolerance in Rice Seeds under Submergence and Their Implication in Rice Biotechnology

Submergence in rice fields creating inundation stress and realizing anoxia or hypoxia is a problem in agriculture. Seeds under this oxygen deficit are faced with fermentative respiration, where the end product would be poisoning the tissue viability. This is more aggravated in direct seeded rice cultivation with the accumulation of lactate as a poison. This review is concerned with the basic insights into anoxia tolerance in seeds and possible strategies to reduce anoxic shock through the modification of metabolism preceded by gene expression. The major concern of anoxic germination is starch metabolism and downstream physiological realization to facilitate escape or quiescence strategy, overcoming submergence stress. The coleoptiles facing hypoxic stress mated with transcripts for oxidative traits, energy metabolism, and proteins for membrane peroxidation in support of energy metabolism are the most important. Hypoxic genes are recovered from traditional indica and japonica land races of rice, and show changes in glycolytic flux and sugar sensing. Anoxic germination and seedling vigor are based on a combinational regulation of oxidative stress and fermentative catabolism. De novo antioxidant and antioxidative enzyme production can support improved seed germination in this condition. Pre-harvest spouting with seed-coat-induced dormancy, hormonal ratios, and hydrolyses would be of concern. Therefore, comprehensive analysis aimed to understand rice seed priming for better gas exchange, diffusion, temperature sensitivity, ion uptake, redox balance, and others. Still, in-depth insights are being awaited for better understanding the physiological and molecular basis using a multi-omics approach for better seed priming to overcome the anoxic/hypoxic revelation mostly acquainted with submergence stress.