Final Germination Research Articles

Improvement Wheat Germination by Using some Biostimulants Substances

A laboratory experiment was carried out at Seed Testing Laboratory, Agronomy Department, Faculty of Agriculture, Mansoura University, Egypt, during November and December 2018 to study the effects of application methods and seeds treatments with some biostimulants on germination parameters of bread wheat Misr 2 cultivar. The experiment was conducted in factorial experiment in Completely Randomized Design (CRD) with 4 replications. The experiment included two factors. The first factor included two application methods with some biostimulants (soaking and priming). The second factor integrated with eleven seed treatments with biostimulant substances. The obtained results showed that the priming method surpassed soaking method in final germination percentage, germination index and co-efficient of germination. Nevertheless, soaking method surpassed priming method in abnormal seedlings %, speed germination index, mean germination time and germination energy %. Treating seeds with yeast extract surpassed the other studied treatments in speed germination index, mean germination time and germination energy percentage. Conversely, treating with mixture of ascorbic acid and salicylic acid surpassed other studied treatments in final germination percentage and germination index. However, treating with mixture of humic acid + amino acid + algea extract + yeast extract surpassed other studied treatments in abnormal seedlings percentage. It could be recommended that priming seeds of bread wheat Misr 2 cultivar with the mixture of ascorbic acid and salicylic acid at the rate of 200 mg/L of each or yeast extract at the rate of 100/L as an effective way for improving germination parameters.

Seed physiological quality and seedling growth of pea under water and salt stress

ABSTRACT The aim of this study was to evaluate seed physiological quality and initial pea (Pisum sativum) seedling development at different water and salt potentials. Polyethylene glycol 6000, sodium chloride and potassium chloride solutions with different osmotic potentials (0; -0.2; -0.4; -0.6; -0.8; -1.0, and -1.2 MPa) were used, and the experiment had a 3 × 7 factorial arrangement. The physiological quality and initial seedling growth characteristics (first germination count, final germination count, strong normal seedlings, epicotyl and taproot lengths, epicotyl dry matter, and root dry matter) were evaluated in a completely randomized experimental design, with four repetitions. Decreases in the observed variables showed that the simulated stress conditions negatively affected physiological performance, germination and initial seedling growth. The water and salt stresses induced by the sodium chloride and potassium chloride solutions were greater than the stress induced by polyethylene glycol 6000.

Quantifying seed germination response of melon (Cucumis melo L.) to temperature and water potential: Thermal time, hydrotime and hydrothermal time models

Quantifying the germination behaviour of seeds against fluctuating environmental conditions can use as a useful tool for seed ecological studies. The response of seed germination rate to temperature (T) and water potential (Ψ) can be described using thermal time (TT), hydrotime (HT), and hydrothermal time (HTT) models. The germination behaviour of Persian melons (C. melo L.) were studied over a range of constant temperatures and water availability to assess the performance of hydro-thermal time models and to provide a data set of germination thresholds and parameters for the Persian melons. The seeds of melons were germinated in the laboratory over a water potential range from 0 to –1.25 MPa at 10, 15, 20, 25, 30, 35, 40 and 45 °C. The results showed that germination percentage was affected by water potential, temperature and their interactions. Germination increased with increasing temperature within the range of 15–25 °C, then decreased as temperature increased from 25 to 45 °C. Furthermore, final germination percentages were reduced with decreasing Ψ, although significant reduction was observed at Ψs less than –0.25 MPa. The model analysis showed that the dynamics of seed germination were generally well described by the TT model within Ψs range < –1 MPa (R2 = 83–96), HT (R2= 0.77–0.93) and HTT models (R2=0.89–0.90). Using the models analysis, the base, optimum and ceiling germination temperatures were estimated to be 9.4, 27.3 and 41.4 °C, respectively. Thermal time analysis showed that thermal time required for germination of Persian melon, Tb and Tc were affected by water availability. Furthermore, the estimated minimum water potential threshold for germination was –1.19 MPa using the HT model, but it shifted towards a higher values with temperatures above or below 25 °C. The amount of hydrothermal time required to germinate was 33 MPa °C days on the suboptimal temperatures range and increased by 36% with increasing temperature from the suboptimal temperatures to the supraoptimal temperatures. The HTT model showed that the Ψb(50) increased by 0.09 MPa with every degree increase in temperature above To. The interaction of Ψ and temperature affected the model parameters and finally the performance of germination models, then varying model parameters with changing environmental condition should be considered for predicting germination time in a complex growth environment.

Seed priming alleviated salinity stress during germination and emergence of wheat (Triticum aestivum L.)

Seed priming is known to often alleviate salinity stress during seed emergence and subsequent crop growth. This study compares the effects of salinity stress on the germination and emergence of wheat (Triticum aestivum L.) seeds untreated (control) and primed with ascorbic acid (Asc), potassium silicate (K2SiO3), proline (Pro), spermidine (Spd) and Lake Urmia saline water (LUsw). Saline water from Lake Urmia (Iran) was diluted to produce salinities with electrical conductivities (EC) of 2, 4, 6, 8, 10, 12, 14, 20 dS m−1, while distilled water (EC ≈ 0 dS m−1) was used for the control. Two independent sets of experiments were conducted. The first experiments were used to select the most effective concentration of each priming agent based on the final germination percentage (GP) and germination rate (GR). The second set of experiments aimed to analyze the measured data in terms of salinity response functions in order to quantitatively determine the most effective priming agent(s). The first experiments showed that the most effective concentrations of Spd (0.5 mM), Pro (25 mM), K2SiO3 (1.5 mM) and LUsw (100 mg L−1) mitigated the negative impacts of salinity on GR by 32, 18, 17 and 22 %, respectively. The second experiment showed that the Maas and Hoffman (1977) and van Genuchten and Hoffman (1984) salinity response functions provided effective descriptions of seedling and early growth response to salinity stress. Mean values of the salinity threshold (EC*) and the salinity at which a given trait was reduced by 50 percent (EC50) in these functions were 3.4 and 10.8 dS m−1 for the control, respectively. By comparison, the EC* values for the K2SiO3, Pro, Spd and LUsw primed seeds were 5.3, 4.5, 4.7, and 4.2 dS m−1, respectively, and the EC50 values were 12.4, 11.4, 11.9, and 9.4 dS m−1, respectively. The beneficial effects of K2SiO3 on seedling growth were more evident than those of the other priming agents. K2SiO3 had the highest effect on EC* and EC50 of the vitality index (VI), showing increases of 151 and 34 %, respectively. The highest increases of EC* and EC50 for seedling dry weight (72 and 24 %, respectively) were obtained with Spd and K2SiO3. The findings provide much insight on relieving the negative effects of salinity through cost-effective seed priming operations so as to improve the production of wheat under saline conditions.

Basic Features of the Analysis of Germination Data with Generalized Linear Mixed Models

Germination data are discrete and binomial. Although analysis of variance (ANOVA) has long been used for the statistical analysis of these data, generalized linear mixed models (GzLMMs) provide a more consistent theoretical framework. GzLMMs are suitable for final germination percentages (FGP) as well as longitudinal studies of germination time-courses. Germination indices (i.e., single-value parameters summarizing the results of a germination assay by combining the level and rapidity of germination) and other data with a Gaussian error distribution can be analyzed too. There are, however, different kinds of GzLMMs: Conditional (i.e., random effects are modeled as deviations from the general intercept with a specific covariance structure), marginal (i.e., random effects are modeled solely as a variance/covariance structure of the error terms), and quasi-marginal (some random effects are modeled as deviations from the intercept and some are modeled as a covariance structure of the error terms) models can be applied to the same data. It is shown that: (a) For germination data, conditional, marginal, and quasi-marginal GzLMMs tend to converge to a similar inference; (b) conditional models are the first choice for FGP; (c) marginal or quasi-marginal models are more suited for longitudinal studies, although conditional models lead to a congruent inference; (d) in general, common random factors are better dealt with as random intercepts, whereas serial correlation is easier to model in terms of the covariance structure of the error terms; (e) germination indices are not binomial and can be easier to analyze with a marginal model; (f) in boundary conditions (when some means approach 0% or 100%), conditional models with an integral approximation of true likelihood are more appropriate; in non-boundary conditions, (g) germination data can be fitted with default pseudo-likelihood estimation techniques, on the basis of the SAS-based code templates provided here; (h) GzLMMs are remarkably good for the analysis of germination data except if some means are 0% or 100%. In this case, alternative statistical approaches may be used, such as survival analysis or linear mixed models (LMMs) with transformed data, unless an ad hoc data adjustment in estimates of limit means is considered, either experimentally or computationally. This review is intended as a basic tutorial for the application of GzLMMs, and is, therefore, of interest primarily to researchers in the agricultural sciences.

Enzymatic activities triggered by the succession of microbiota steered fiber degradation and humification during co-composting of chicken manure and rice husk

The carbon to nitrogen ratio (C/N) is well known for its importance in the composting process, however the fiber degradation and humification associated with enzymatic activity and microbial variation derived from different C/N ratios are poorly studied. Here, we designed two treatments of chicken manure with 15% (initial C/N ratio 9.61) and 50% (initial C/N ratio 17.3) rice husk to adjust the moisture of mixtures for turning feasibly by towable fertilizer turner in industrial level. Compared to the C/N ratio 9.61, the suitable C/N ratio of 17.3 significantly enhanced the composting efficiency and the final germination index (23.7%). Moreover, the suitable C/N ratio increased the relative abundance of Bacilli, which played an important role during the mesophilic and thermophilic phases. Bacilli abundance was related to cellulose and β-glycosidase activities, thus improved fiber degradation and humification. This study not only seeks a swift method in industrial level to process chicken manure but also provides insight into the enzymatic activity of microbial community related to high-efficient composting.

Germination Test of Shea Seeds (Vitellaria paradoxa C.F. Gaertn) in Nursery on Substrates of Northern Côte d’Ivoire

Aims: The present study aims to evaluate the effect of some abiotic factors on the quality of seed germination of shea tree, a plant of great economic interest for the rural populations in Northern Côte d'Ivoire.&#x0D; Study Design: The trials were conducted in a nursery where two factors were considered. These were the substrate, with six modalities and shelter with two modalities. Six small pits, each of size 60 x 60 cm, surface 3600 cm2 and 15 cm of depth were dug and then filled with different substrates.&#x0D; Place and Duration of Study: The work was carried out in 2018 in the district of Korhogo in Northern Côte d'Ivoire.&#x0D; Methodology: Each treatment received 36 seeds of shea tree giving a total of 216 seeds per test. The seeds used were all dark brown, ellipsoid in shape with masses ranging from 10 to 11 g. The experiment was carried out with a total of 12 treatments, six under a greenhouse hermetically covered with transparent polyethylene plastic and six under a shade made up of a rack covered with maximum Panicum leaves. &#x0D; Results: The first germination was observed at the level of the organic manure treatment at 6 months of degradation installed under the greenhouse (ManB_G = 28 days). The lowest final germination rate was obtained with the organic fertilization at 3 months of degradation installed under the shade (FGP ManA_S = 2.95%) while the highest was observed in the sawdust installed under the greenhouse (FGP S_G = 64.18%).&#x0D; Conclusion: It is concluded that for each substrate, soil or biowaste, the seeds of shea tree have a better ability to germinate under a greenhouse than under a shelter covered with straw.

Breaking seed coat impermeability to aid conservation and utilization of wild Vigna species

The extent of hardseededness due to seed coat impermeability and pre-treatments to overcome it have been worked out in 34 accessions comprising 14 species of V. luteola (Jacq.) Benth. Mart., V. vexillata (L.) A. Rich., V. wightii (Bedd.) Babu and S.K.Sharma, V. pilosa (Klein ex.Willd.) Baker, V. parkeri Baker, V. reticulata Hook. f., V. dalzelliana (Kuntze) Verdc., V. hainiana Babu, Gopinath and S.K.Sharma, V. trinervia var. bourneae Gamble, V.radiata var. sublobata (Roxburgh) Verdc.(6), V. radiata var. setulosa (Dalzell) Ohwi and Ohashi, V. membranacea A.Rich., V. stipulacea (lam.) Kuntze, V. racemosa (G Don) Hutch. & Dalziel. The percentage of hard seeds ranged from 45 to 95 within accessions and species tested. All the pre-treatments, which are mechanical scarification, hot water soaking at 50 °C for 15, 25 and 30 min and at 80 °C for 15 and 30 min, reduced hard seed percentage and increased final germination significantly (p < 0.01) as compared to the controls. There were significant differences between the species, treatments and species over treatments. In general, mechanical scarification was the best pre-treatment in most of (eleven out of fourteen) species studied with germination ranging from 73 to 100% among the species. This was followed by hot water at 50 °C for 30 min (40–100%) and hot water at 50 °C for 25 min (43–99%).

Jačina varijabilnosti morfološkog i funkcionalnog sjemenskog polimorfizma različitih majčinskih biljaka ambrozije (Ambrosia artemisiifolia L.) iz istih populacija

The aim of the research was to determinate the degree of variation in morphological (seed weight) and functional polymorphism (final germination, dormancy, seed mortality and germination dynamic) within two seed populations of Ambrosia artemisiifolia L. Seeds were collected separately from 20 plants/population in Jastebarsko (45°40'18˝N; 15°39'03˝E), population-J and Popovaca (45°34´1˝N; 16°40´43˝E), population-P in 2014. Seed weight of J and P populations had weak variability (CV-J = 18.2%, CV-P= 29.8%) with an average of 4.05 g (J) and 4.54 g (P). Estimated variability was strong for amount of death seeds in the J (CV = 67.6%), but weak for geminated (CV = 4.9%) and moderate for dormant seeds (CV = 51.0%). Variability within P population was moderate for both germinated and dead seeds (CV = 34.5%; 34.1%), while variability within amount of dormant seeds was weak (CV = 14.2%). Variability in medium germination (T50) was relatively low for both experimental populations (CV – J = 12.0%; CV – P = 22.4%). Despite determined intrapopulation variation, degrees of variability between researched parameters (final germination, dormancy and medium germination – T50) were weak or moderate and therefore acceptable for further experiment base on seed testing.

SEED GERMINATION AND MORPHO-PHYSIOLOGICAL CHARACTERIZATION OF THREE TOMATO (LYCOPERSICON ESCULENTUM) VARIETIES IRRIGATED WITH TREATED WASTEWATER

The ability to reuse treated wastewater (TWW) would be of significant benefit to agriculture whilst at the same time providing a valuable water resource. This study concerned the effects of three various levels of treated wastewater (0%, 50% and 100% TWW) on seed germination and plant development of three different varieties of tomato (Lycopersicon esculentum) (viz. Toufan, Heinz and Bouzina). Irrigation with TWW persisted 15 days for the germination stage and 120 days for the growth and development stage. A control plot irrigated with a pure water (groundwater) was also set up in order to compare the seeds and the plants response to different concentrations of irrigation water. The final germination was expressed as a percentage of the total number of seeds in each treatment. This study has demonstrated that treated wastewater improves the germination in Heinz variety and had no effect on both Toufan and Bouzina varieties whether it is pure or diluted by half. For the growth stage, the statistical analysis showed that the Toufan variety has tolerated successfully the TWW irrigation with its high and moderate concentrations, and this by analysing all the morpho-physiological parameters studied in this work (leaves numbers, stem and root length and dry biomass, relative water content and rate water loss).

SEED GERMINATION AND SEEDLING ESTABLISHMENT OF CHERIMOYA (ANNONA CHERIMOLA MILL.) AT DIFFERENT TEMPERATURES

Cherimoya (Annona cherimola Mill.) has an exceptional flavor and aroma, which makes it a fruit with great potential. However, little is known about its propagation by seeds. According to the scientific literature, the germination of cherimoya seeds is affected much more by external conditions than by internal conditions. Germination of cherimoya variety ‘Concha Lisa’ were tested for germination at constant temperatures of 25, 30, 40°C, and at room temperature, varying from 20-25°C, coupled with total darkness. Seeds were sown in Petri dishes (0.8% agar water), for 25 days of incubation. The kinetics of germination was determined according to five closely related parameters, viz. final germination percentage (FGP), mean germination time (MGT), coefficient of velocity of germination (CVG), time to 50% germination (T50) and seedling length (SL). The temperature of 30°C was found optimally suitable with 70.8% FGP, 17.5 days MGT and 3.91 cm SL, while the room temperature of 20-25°C slightly improved germination with only 25% FGP. Furthermore, significant decrease in FGP and SL was observed at 25°C and 40°C of temperature in comparison to 30°C. The analysis also revealed that cherimoya seed germination, day 10-15 after seed sowing is suitable for final counts. An overview on the emergence of cherimoya seedlings, during a 12-week period in pots is presented.

Seed Germination Traits of Loquat (Eriobotrya japonica Lindl.) As Affected by Various Pre-Sowing Treatments (Cutting of Cotyledons, Removal of Perisperm, Moist Chilling and/or Exogenous Application of Gibberellin)

The purpose of this study was to investigate the effects of various presowing treatments on the germinability (final germination percentage) and germination rate of loquat seeds in order to increase seedling production in nurseries (applied research) as well as provide answers for important physiological issues related to loquat seeds and their seed coat (basic research). Three experiments were carried out with various pre-sowing treatments. These treatments included full or partial removal of seed coat (perisperm), partial cutting of cotyledons as well as moist chilling at 5°C for 13 days and/or soaking the seeds in water or 250 ppm gibberellic acid (GA3) solution for 24 h. According to the results, cotyledons excision resulted in delayed germination, regardless of the presence or absence of the seed coat in comparison with the decoated seeds that demonstrated the highest germination rate amongst them. In addition, even the partial excision of seed coats affected positively both the germinability and the germination rate, compared to the control-intact seeds. Furthermore, control-intact seeds had a higher germination percentage when exposed to moist chilling independently of the application or not of gibberellin; while the combination of gibberellin application and moist chilling improved both the percentage and the rate of germination of decoated seeds. In conclusion, the role of perisperm (seed coat) in the germination procedure of loquat seeds seems to be important, indicating the existence of seed coat-imposed dormancy on loquat seeds. Finally, the existence of a mild endogenous embryo-dormancy on loquat is also discussed.

Seed germination and antioxidant enzyme activity in seedlings of diploid and tetraploid bahiagrass under water restriction

ABSTRACT: The objective of the following research was to investigate the physiological responses of two bahiagrass genotypes (Paspalum notatum Flügge) submitted to water restriction, induced by polyethylene glycol (PEG6000), during seed germination. Seeds of cv. Pensacola (diploid) and Bagual ecotype (tetraploid) were placed on paper moistened with osmotic solutions at potentials of 0.0; -0.1; -0.2 and -0.3 MPa. Composed of two subsamples of 100 seeds and four experimental units per treatment, the germination test was conducted in a germination chamber under alternating temperatures of 30 °C (8 hours) and 20 °C (16 hours), with presence of light during the higher temperature. Final germination percentage and germination speed index of the seeds, as well as early growth, activity and expression of antioxidant enzymes of seedlings were evaluated. The water restriction induced by PEG6000 reduced the percentage of germination in Pensacola (from 74% to 59%) and Bagual (34% to 10%). For the latter, the evaluation of seedlings showed higher dry mass in relation to cv. Pensacola (1.7 times higher in root and 1.6 times in shoot). In response to moderate water restriction, the genotypes showed increases in root growth (1.7 times higher in -0.1 compared to 0.0 MPa), both in expression and enzymatic activity (superoxide dismutase and catalase).

EFFECT OF COLD STRATIFICATION ON SEED GERMINATION OF THE MULTIPURPOSE FRUIT SHRUB, ZIZIPHUS LOTUS (L.) LAM. (RHAMNACEAE)

Shrubs and trees of the genus Ziziphus are a good example of naturally occurring multipurpose plant species with great potential in arid regions. This study was conducted to investigate the effect of cold stratification on seed germination and seedling growth of Ziziphus lotus (L.) Lam. Seeds were subjected to 0, 45, 90 and 120 days of cold stratification at 5°C. We also examined fruit, kernel and seed morphology. For each treatment period, four replicates of 50 seeds were incubated in plastic containers between two layers of moist sand at 15% and under greenhouse conditions for 15-day period. At the end of the experiment, the final germination percentage (FGP), shoot length and root length were assessed. The results clearly indicated that increasing duration of cold stratification improved seed germination. The most effective stratification period was 120 days where Z. lotus recorded 83% of FGP and 16.5 cm of total seedling length. Cold stratification treatments significantly increased shoot height, root length, as well as seedling total length. 120 days stratification treatment resulted in the highest shoot and root length (6.80 cm and 9.75 cm, respectively). An overview on the emergence of Z. lotus seedlings during a 15-day period was also illustrated.

Hydrological and thermal responses of seeds from four co-occurring tree species from southwest Western Australia.

Seed germination is a critical stage in the life cycle of most plants and is defined by specific tolerance thresholds beyond which rates and success of germination rapidly decline. Previous studies have demonstrated that widespread plant species commonly germinate over a broad range of temperatures and water stress levels, whereas range-restricted species often exhibit a narrower germination window in terms of temperature and moisture. We investigated the relationships of the key germination traits of maximum germination (G max) and time to 50% germination (t 50) in response to temperature (5-35°C) and water stress (-1.5-0MPa) in four co-occurring Western Australian native Eucalyptus species with widely varying biogeography. Eucalyptus caesia subsp. caesia and E. ornata exhibit a highly localized distribution and a narrow geographical range, being restricted either to granite outcrops or the upper slopes and tops of lateritic rises, respectively. These two species were compared with the two widespread and dominant congenerics E. salmonophloia and E. salubris. There was a distinctive hump-shaped response of t 50 to temperature and an exponential response to water stress, characteristic of rate- and threshold-limited processes, but no consistent pattern in the response of G max. The four species were significantly different in their thermal performance of t 50, with E. caesia and E. ornata displaying narrower thermal tolerance ranges than the two widespread species. In terms of mean final germination percentage, the two range-restricted endemic taxa exhibited higher lability in their response to thermal stress and drought stress compared to the two broadly distributed congenerics. These findings indicate a link between distributional extent, temperature and water stress tolerance and may have implications for identifying ecological filters of rarity and endemism.

Physiological performance of Garcinia gardneriana (Planch. &amp; Triana) Zappi: a species with recalcitrant and dormant seeds

Abstract: Garcinia gardneriana (Planch. &amp; Triana) Zappi is a native species widely distributed in Brazil. It has ornamental features, edible fruits, and its leaves have medicinal properties; however, its potential has not been explored. The aim of this study was to evaluate seed physiological performance due to dormancy, desiccation and storage tolerance. Only decoated seeds germinated. Seeds had an initial water content of 1.07 g H2O.g-1 dw and final germination of 95%. Both desiccation to 0.67 g H2O.g-1 dw and storage at 25 ºC for ninety days resulted in decreased germination, 43 and 41%, respectively. Desiccation below 0.25 g H2O.g-1 dw and storage for ninety days at 5 ºC were lethal. A rapid decrease in enzymic protection by superoxide dismutase and ascorbate peroxidase was correlated to desiccation sensitivity. Total polyamines content was higher in fresh seeds and markedly decreased with desiccation. The decrease in enzyme activity and polyamines content seems to be associated with seed viability loss. In sum, G. gardneriana seeds have a low tolerance to desiccation and are sensitive to chilling. Therefore, the seeds can be categorized as recalcitrant and dormant, a rare combination in terms of seed biology.

Efeito alelopático do extrato aquoso das folhas de Callistemon viminalis (Sol. ex Gaertn.) G.Don sobre a germinação de picão-preto (Bidens pilosa L.)

O picão-preto é uma planta daninha encontrada em lavouras anuais e perenes no Brasil. Em decorrência da aplicação de produtos químicos alguns biótipos da espécie B. pilosa tem apresentado resistência, dessa forma estudos recentes têm avaliado a eficiência de substâncias alelopáticas como alternativa no controle do picão-preto. Neste contexto, o objetivo do trabalho foi avaliar o efeito alelopático das folhas de Callistemon viminalis sobre a germinação de picão-preto. Para tal, foram avaliadas cinco concentrações de extratos de C. viminalis 0% (testemunha), 20%, 25%, 50%, 100%, em delineamento experimental inteiramente casualizado, com quatro repetições. A qualidade das sementes foi avaliada por meio da avaliação da germinação das sementes, realizando-se leituras diárias durante quatorze dias. Os dados foram submetidos ao pacote Seedcalc, gerando variáveis de germinação final e índices de vigor, os quais foram submetidos ao teste de Shapiro-Wilk a (p≤0,05), seguido do teste de Scott-Knott (p≤0,05), utilizando-se do software R. O extrato de C. viminalis provocou efeitos negativos e positivos na germinação e nos índices de vigor das sementes, sendo a concentração de 20% estimulante e as concentrações de 25%, 50% e 100% inibitórias. Portanto os extratos de C. viminalis apresentaram ação alelopática na germinação de sementes de picão-preto.

Germination and seedling growth responses of Sri Lankan grown Sesame/Thala (Sesamum indicum L.) for simulated drought conditions

The agriculture sector is often challenged by dry weather, thus a better understanding of growth responses of crops to changes in climate is imperative. However, drought responses of many economical crops are yet to be comprehensively studied. Therefore, this research was carried out to investigate the responses of 10 Sri Lankan grown sesame varieties/cultivars: Uma, Malee, Idal, Pokuru, Black-seeded sesame and its wild relatives, to reduced water availability during germination and seedling growth. Drought conditions were simulated in a laboratory with three different treatments [polyethylene glycol (PEG) 6000, mannitol and sodium chloride] at 0, - 0.25, - 0.5 and -1.0 MPa water potentials under complete randomised design with 10 replicates each having eight seeds per petri plate per variety/cultivar. The final germination percentage of sesame seeds after 10 days was calculated. Seedlings were further exposed to the same treatments and their root and shoot lengths were measured after 10 days. Germination was assessed using binary data analysis and the seedling data were subjected to ANOVA. Results revealed that the highest tension of PEG (-1.00 MPa) inhibited seed germination and the emergence of seedlings, while that of mannitol (-1.00 MPa) negatively affected seedling growth only (p

Heteromorphic seeds of wheat wild relatives show germination niche differentiation.

Crop wild relatives are fundamental genetic resources for crop improvement. Wheat wild relatives often produce heteromorphic seeds that differ in morphological and physiological traits. Several Aegilops and Triticum species possess, within the same spikelet, a dimorphic seed pair, with one seed being larger than the other. A comprehensive analysis is needed to understand which traits are involved in seed dimorphism and if these aspects of variation in dimorphic pairs are functionally related. To this end, dispersal units of Triticum urartu and five Aegilops species were X-rayed and the different seed morphs weighed. Germination tests were carried out on seeds, both dehulled and left in their dispersal units. Controlled ageing tests were performed to detect differences in seed longevity among seed morphs, and the antioxidant profile was assessed in terms of antioxidant compounds equipment and expression of selected antioxidant genes. We used PCA to group seed morphs sharing similar patterns of germination traits, longevity estimates and antioxidant profile. Different seed morphs differed significantly in terms of mass, final germination, germination timing, longevity estimates and antioxidant profile in most of the tested species. Small seeds germinated slower, had lower germination when left in their dispersal units, a higher antioxidant potential and were longer-lived than large seeds. The antioxidant gene expression varied between morphs, with different patterns across species but not clearly reflecting the phenotypic observations. The results highlight different trait trade-offs in dimorphic seeds of Aegilops and T.urartu, affecting their germination phenology and longevity, thereby resulting in recruitment niche differentiation.

Improvement of barley (Hordeum vulgare L.) germination by application of biochar leacheate in steeping solution to upgrade malt quality.

To investigate an improvement of barley germination by application of biochar leacheate in the steeping solution for upgrading malt quality. Barley germination was improved when biochar leacheate was used in the steeping water during the first steeping cycle. A clear decrease in the time to reach 50% of final germination percentage was detected due to an addition of biochar leacheate, but no significant difference was observed in the percent germination at the end of germination. Hydrolase activities including α-amylase, proteinase and β-glucanase in barley grains were maximally increased during the malting process when 10% biochar leacheate was added to the first steeping water. The wort yielding indexes including both glucose and maltose content and the free amino nitrogen content were significantly increased but the β-glucan content was significantly decreased at a level of p < 0.05 when 10% biochar leacheate was added to the steeping water. Biochar leacheate could be used as a stimulator in the steeping solution during the first steeping cycle to improve barley germination and so upgrade malt quality.