Mean Germination Percentage Research Articles

Effect of ultrasonic treatment on seed germination and seedling emergence in seven vegetable species

This study was performed to determine the effect of ultrasound treatment on seed germination, seedling emergence and mean germination and emergence times in seeds of watermelon, melon, leek, pepper, carrot, tomato and aubergine. Seeds treated with 40 kHz ultrasound over 30 minutes (US), hydroprimed seeds (HP) and dry controls (C) were tested. US-treated seeds had 85% mean germination percentages compared to 82 and 78% for HP and C seeds, respectively. Corresponding values for seedling emergence were 83, 75 and 72%. US treatment reduced mean germination and emergence times. The maximum advantages obtained from US in germination were observed in watermelon (13%), carrot (11%), pepper (13%), leek (10%), and pepper (7%) compared to C and HP seeds, respectively. Advantages in seedling emergence obtained by US were greatest in watermelon (20%), leek (22%) and tomato (13%) compared to C and for pepper (14%), tomato (12%), melon (11%), watermelon (10%) and leek (10%) compared to HP. US treatment reduced both germination and emergence times. Results showed that US treatment was more effective on seedling emergence than germination. US treatments have the potential to increase germination and seedling emergence in vegetable seeds.

Seed propagation, adaptation to cultivation conditions, determination of ornamental plant properties, and ex situ conservation of the endemic species Centaurea hermannii F. Hermann

This study focused on seed propagation and ex situ conservation of the endemic species Centaurea hermannii F. Hermann. Plant properties such as vegetation cycle, adaptation to the cultivation environment, morphological characteristics of the plants and seeds, and esthetic properties as an ornamental variety were investigated. The percentage of viability of the seeds, as well as the effects of different seed germination methods when applied to the germination speed, were also explored. C. hermannii specimens planted in soil adapted quickly under field conditions and flowered over a period of two months, with a bright-orange color and glossy blossoms. In addition, the plants displayed all the type-specific botanical and esthetic properties, as well as provided value as an ornamental plant. An ex situ conservation area was created with the plants collected. To determine the best germination conditions for C. hermannii seeds, various methods were explored. Among these, a combination of 200 ppm of GA3 treatment during a three-month storage period at 4 °C, followed by cold-wet stratification at 4 °C for three months, produced the best results in terms of mean percentage germination (70.5 %) and mean germination speed (3 days).

Effect of storage period on different seed viability parameters in rajmash (Phaseolus vulgaris)

Seed longevity mainly depends on initial seed quality and storage conditions therefore; farmers and gene bank curators need to be aware of the storage potential of rajmash cultivars that contribute to the production of high quality seed during routine germplasm regeneration/multiplication. Consequently, it is important to generate information on seed longevity of rajmash. In the present investigation, 14 high yielding rajmash cultivars were stored for 4 years and periodical germination percent, time to initiate germination (t1), time to achieve 50% germination (t50) and uniformity of germination (U7525; time between 25 and 75 % germination) were recorded. The varieties exhibited the mean germination percentage of 93, 93, 73, 3 and 0.9 when stored for 0, 1, 2, 3 and 4 years, respectively. The results demonstrated that, all the 14 varieties could be safely stored for a minimum period of 1 year at ambient condition. Seven varieties (Arka Komal, IPR 98-5, IPR 98-3-1, HUR 137, HUR 203, HPR 35, Gujarat Rajmash 1) could be stored for 2 years as they demonstrated more than the minimum germination requirement (75%) of Indian Minimum Seed Certification Standard. Storing seeds for extended period not only decreased the final germination percentage, but also increased the time for t1, t50 and t7525, suggesting that use of aged seeds could result into poor field establishment coupled with delayed and non-uniform germination.

Germination responses of Cola acuminata (Pal. De Beauv.) seeds to different substrates, photoperiods and dehydration

Cola acuminata (Pal. De Beauv.), one of the many forest tree species which are of socio-economic importance in Western and Central Africa, is still exploited in the wild by subsistence farmers because it has not been domesticated yet. As a contribution to its domestication, the present study aimed at determining germination requirements and desiccation tolerance of seeds. Three substrates (forest topsoil, river sand and mixture of forest top soil and river sand), two photoperiods (12 hours/day and continuous darkness) and dehydration were investigated for their effects on seeds germination percentage. To evaluate the seeds’ tolerance to desiccation, fresh seeds were dried at laboratory temperature for 16 days during which seeds moisture content, seeds germination percentage and electrical conductivity of seeds leachate were monitored at two-day intervals. Results showed that the mean germination percentage recorded on the mixture of forest top soil and river sand (97.2 ± 1.0%) was significantly higher than that recorded on forest topsoil (85.5 ± 4.0%), which was in turn higher than that obtained on river sand (70 ± 1.5%). The effect of photoperiod on germination percentage was not significant (p = 0.112). As response to seeds drying, the mean germination percentage slightly decreased as moisture got lost, then drastically dropped when moisture content was below 45.95 ± 4.2%. Seeds failed to germinate when their moisture content fell below 27.1 ± 2.1%. Electrical conductivity of seed leachate exhibited a highly significant negative correlation with both germination percentage (p ˂ 0.01, r = -0.926) and moisture content (p ˂ 0.01, r = -0.931). It is concluded that the best substrate for C. acuminata seeds’ germination is the mixture of forest top soil and river sand in a 1/1 (v/v) ratio. Cola acuminata seeds are desiccation-sensitive and their storage behavior is recalcitrant. This is a significant constraint for conservation that should be addressed in further researches.Keywords: Cola acuminate, seed germination, photoperiod, desiccation tolerance, moisture content, storage behavior.

Comparative Effects of Rice and Melon Wastes on Sitophillus Zeamais, Storage Pest of Maize Grains in Nigeria

World’s calories supply from maize accounts for 20% but global postharvest grain loss caused by insect pests was estimated to be 10%. Control is mostly by synthetic insecticides with consequences such as insect resurgence and resistance and negative effect on non- target organisms. Maize grain losses to weevils are so enormous that effective local solution has to be sought. Thus this research aimed at assessing the effectiveness of powders and ash of rice husk and melon shell in controlling Sitophillus zeamais (Mots) in stored maize. Four treatments, Rice husk powder (RHP), Rice husk ash (RHA), Melon shell powder (MSP) and Melon shell ash (MSA) were applied at eight levels of 0 - 2.0 g 20 g-1 maize grain in three replicates. Five pairs (males and females) of freshly emerged S. zeamais were introduced into each treatment. Mortality test was carried out on the insects at 48 and 96 hours after introduction. Germination test was conducted on ten randomly selected grains after weevil emergence. Significantly higher (p≤0.05) mortality was recorded in treated seeds than the control. Virtually 100% mortality of S. zeamais was attained in both RHA and MSA treated maize in 96hrs at all application rates. Mean adult emergence in maize treated with both RHA and MSA were zero, with no weight loss like those of grains treated with standard control of P. guinensis. Also maize grain treated with Rice husk ash (RHA) and Melon shell ash (MSA) recorded a mean WPI of zero irrespective of application rates as in P. guinensis. The mean percentage germination of maize grain was significantly higher (p≤0.05) in P. guinensis than those recorded on treatments, while germination of treated maize is higher than the control. Thus rice husk and melon shell are effective alternatives to insecticides against S. zeamais in stored maize.

Effects of smoke water on germination, seedling vigour and growth of Sceletium tortuosum

Sceletium tortuosum (L.) N. E. Br. is a South African protected species widely utilized in traditional medicine. The plants' mesembrine-type alkaloids have immense potential in modern pharmacology as treatments for numerous medical and psychological disorders. Fresh plant material is paramount for researchers and pharmaceutical companies as it is presently the only available alkaloid source. Although S. tortuosum is a conservation concern and valuable to the pharmaceutical industry, information on germination behaviours of this species is scant. This study highlights the effects of the bio-stimulant smoke water (SW) on germination, seedling vigour and growth of Sceletium tortuosum in vitro. A standardized smoke extract was diluted to concentrations of 1:500, 1:1000, 1:1500, 1:2000, 1:2500 (v/v). Seeds were pulse-treated with SW solutions for 1, 2, 8 and 24 h. The study included positive and negative control treatments. The highest mean germination percentage and germination rate were recorded for 1:1000 SW for 24 h (83 ± 1.9%) and 1:2500 SW for 24 h (6.35 seeds germinated/day). Vigour index was highest for 1:1000 SW (24 h). Smoke water only improved seedling growth when germination occurred slowly. Although mean shoot length was optimal for 1:2500 (1 h) – 4.19 ± 0.15 mm – mean root length and seedling size were highest in the negative and positive (1 h) control treatments. This investigation showed that SW effectively improved germination and seedling vigour of S. tortuosum, however, alternatives must be investigated to optimize seedling growth when this biostimulant is applied.

Impact of Seed Maturation and Drought on Seed Germination and Early Seedling Growth in White Clover (Trifolium repens L.)

Background: Understanding the drought tolerance of white clover seeds during germination and early seedling growth and how that is linked to seed maturation in legume species, is crucial to developing new stand establishments.Methods: An experiment was conducted in Randomized Block design in two factorial concept to explore how seed maturation and drought tolerance influence seed germination and early seedling growth using the two factors: seed coat color (yellow and brown, two levels as one factor) and drought intensity (control: 0 MPa [distilled water], mild drought: -0.2 MPa, moderate drought: -0.4 MPa and severe drought: -0.6 MPa, four levels as another factor).Result: In contrast to the yellow-coated seeds, the mean germination percentage, germination index, seedling vigour index and radicle length of the brown-coated seeds were lowered by 7.9%, 23.1%, 20.5% and 12.9%, respectively. Compared to the control, introducing drought conditions reduced the mean of germination percentage, germination index, seedling vigour index and radicle length of yellow-coated seeds by 52.4%, 64.1%, 41.9% and 23.2%, respectively. Meanwhile, drought affected brown-coated seeds more than yellow-coated seeds. The results indicating that the seed quality of white clover seed lots with yellow-colored coats higher than the seed lots with brown-coloured coats. In agronomic practice, a larger proportion of yellow-coated seeds should be harvested to improve new stands successful establishment under environment easy to dry.

Rapid generation cycling transforms pyrethrum (Chrysanthemum cinerariifolium) into an annualized perennial

AbstractPyrethrum [Chrysanthemum cinerariifolium (Trevir.) Vis.] is an important “green pesticide” crop widely used for insect control on plants and for humans. Pyrethrum flowers have the highest Pyrethrin I/Pyrethrin II ratio (%Py) and are harvested at specific stages to maximize yield. Selection for correlative early seed germination and flowering in first year pyrethrum seedlings is challenging and has not been accomplished previously. The breeding objectives for this study were to sample a wide germplasm base to select for rapid generation cycling (RGC) traits of early and high germination in Weeks 1–4, earliness of visible bud date (VBD) and flowering, accelerated growth, high leaf unfolding rates per week, number of shoots, and %Py in the 1st–12th flowers. Seven seed lots were evaluated for germination rate and timing (N = 141,120 seeds) in Year 1 for RGC traits. Seedling germination was recorded weekly with toothpicking to identify germination weeks with successive selection occurring at transplanting. Grand mean percentage germination was low (24.5%), whereas individual seed lots varied (18.4–38.9%). Seedling death was 0.0–6.8%. On average, it took 34–39 wk to reach VBD and an additional 3–4 wk to flower. Thus, flowering in <1 yr without vernalization is a new trait (annualized perennial) selected in this crop. Germination week was significantly correlated with VBD and flowering dates and is an important trait to use for selecting early‐flowering genotypes in plug trays. Pyrethrum breeding programs could select the earliest germinating seedlings (Weeks 1–4 after sowing) at transplanting to enhance the likelihood of selecting early‐flowering genotypes in the first year and provide an additional year of harvest to increase yield.

Performance of Pod Orientation at Sowing on Germination and its Related Attributes in Peanut (Arachis hypogaea L.)

Background: A Field experiment was conducted at Agricultural College and Research Institute, Madurai, India during summer, 2020 to evaluate performance of different orientations of double pod sowing in comparison with kernel sowing (practice) on germination variability, yield and its related parameters of peanut. Methods: The experiment set up with four treatments replicated four times with pods sowing orientations viz., i) Sowing with vertical posterior-upwards ii) Vertical posterior-downwards iii) horizontal sowing and iv) sowing with kernels. Result: Results showed a little variation in germination between sowing orientation of double pods compared to kernel sowing. Though, mean germination percentage, germination energy, germination value and emergence energy value were higher in kernel sowing, pod sowing with vertical-posterior downwards elevated germination percent up to 97.45% and also inflated germination attributes and yield.

The Effectiveness of Different Priming Treatments on Seeds of Eggplant (Solanum melongena L.) Varieties

Bu araştırmada, farklı patlıcan çeşitlerine ait tohumların hidropriming (HP), ozmopriming (OP) ve termopriming (TP) uygulamalarının tohum çimlenme kalitesi üzerine etkileri araştırılmıştır. Manisa kır çizgili (MKÇ), Kemer 27 (K) ve Aydın Siyahı (AS) çeşitlerinin farklı olgunluk seviyelerinde hasat edilen (çiçeklenmeden sonraki 50, 55, 60 ve 75 gün sonra) patlıcan tohumları 35 0C’de 4 ve 8 saat (1:2/karanlık-aydınlık koşulda) süre boyunca, %10’luk PEG-6000 ile OP, 35 0C’de 4 ve 8 saat (1:2/karanlık-aydınlık koşulda) sürede saf su ile HP ve 50°C’de 2 farklı sürede (15 ve 30 dakika) su banyosunda TP işlemlerine tabi tutulmuştur. Tüm çeşitlerde kontrol ve uygulama gruplarında tohum nem miktarları belirlenmiştir. Uygulamalar sonunda tohumlar yüzey kuruluğu sağlanıncaya kadar bekletilerek ardından petri çimlendirme testine tabi tutulmuştur. Denemeler sonucunda, patlıcan tohumlarının OP, HP ve TP uygulamaları ile canlılık (ortalama çimlenme oranı ve süresi, fide kök-sürgün uzunlukları) bazında değerlendirilmiştir. İncelenen parametreler değerlendirildiğinde, priming olumlu etkisi tohumların olgunluğu ile ilişkili olduğu görülmüştür. Bağımlı değişkenler olan normal ve toplam çimlenme parametreleri; priming, çeşit, olgunluk ve bunların interaksiyonu ile istatistiksel olarak anlamlı bulunmuştur (p

Variations in seed quality of primed onion seed lots during storage at -20°C

This work was carried out on twenty onion seed lots to test changes in seed quality during storage at -20°C after priming treatment. Seeds were matric primed at 20°C by mixing seed, vermiculite and water at the ratio of 2:1:3 for 48 hours at 15°C and subsequently dried to 7% seed moisture content. They were then hermetically stored at -20°C over 60 days, and samples were taken after 0 (unstored), 15, 30 and 60 days. Seed germination percentages (20°C, 12 days) and mean germination times were determined. Results indicated that mean germination percentages of the control and primed but not stored seed lots were 80 and 85% respectively. Germination percentages after 15 and 30 days at -20°C remained as high as those of primed and unstored seeds, which were 87%. However, by 60 days after storage, primed seed germination percentages were reduced to 82%, which was non-significant compared to the control. The fastest germination - the lowest mean germination times - were also recorded as 3.64 days after 30 days of storage (p<0.05). Results indicated that the benefit obtained from priming may remain in onion seeds for about 30 days after storage at -20°C. Extended storage of up to 60 days can reduce the advantage that is obtained from priming. Storage of primed onion seeds at freezing temperatures can be an alternative method to reduce seed ageing and to maintain high seed quality longer for a certain period.

Temperature fluctuation improves oil palm (Elaeis guineensis) dura × pisifera seed germination

Oil palm is mainly propagated using dura × pisifera (D × P) hybrid seeds. Among the issues in D × P seed production are relatively poor seed germination and uniformity, despite heat treatment at 40°C to break dormancy. The conditions for germination post-heat-treatment may be a contributing factor. This study aimed to evaluate and compare the effect of constant 30°C or ambient temperature fluctuation at two different locations, Sime Darby Oil Palm Breeding Seed Processing Renggam, Johor and the Seed Production Unit (SPU) Banting, Selangor on oil palm D × P seed germination. At both locations, final mean germination percentage and speed were higher at fluctuating temperatures compared with constant 30°C. Under fluctuating conditions, the Oil Palm Breeding Seed Processing Renggam environment resulted in higher germination (85.8%) compared with SPU Banting (69.8%). Thus, the higher temperature amplitude (difference between daily maximum and minimum temperatures) was an important factor, resulting in higher germination. Therefore, oil palm can be germinated under ambient temperature conditions to obtain higher germination than under constant temperature, avoiding the need for maintaining expensive constant temperature germination rooms. In addition, a sufficiently high temperature amplitude can be beneficial in improving the ability to germinate and the speed of germination.

WILD MEDICS FROM DIFFERENT ORIGINAL HABITATS CAN BE USED AS FORAGE LEGUMES IN SALT AFFECTED SOIL

Legumes are a key player in sustainable agriculture. They are a potential tool as forage for reclamation of saline soils. However, still there is a need to balance between tolerance of the forage during different developmental stages and its productivity. The present work aimed to study salinity tolerance of four wild Medicago species, as an initial step to select new species that can be grown in salt-affected soils or used as wild relatives to improve alfalfa. Seeds of M. polymorpha, M. intertexta, M. truncatula and M. lupulina, collected from different natural habitats, as well as alfalfa were germinated under different salinity levels to evaluate germination percentage and germination speed. Generally, seeds of M. truncatula collected from desert habitat showed the highest mean germination percentage followed by alfaalfa, while seeds of M. intertexta collected from salt-affected habitat exhibited the highest mean germination speed, followed by M. lupulina. Under severe salt stress, M. intertexta exhibited the highest aerial biomass index, followed by M. truncatula and M. lupulina, while M. polymorpha and alfalfa came as inferiors. Mineral contents and ion leakage of the studied species were determined and discussed. M. intertexta, M. truncatula and M. lupulina, collected from stressful habitats, tended to maintain osmotic and ionic homeostasis by relying on accumulation of the less energetic cost ions (Na+) in roots and sugars and K+ in shoots scoring the highest aerial biomass and tolerance index, orderly. Therefore, the results recommend cultivating these species in salt-affected lands or using them as wild relatives to improve alfalfa.

Origin-dependence of variation in seed morphology, mineral composition and germination percentage in Gynandropsis gynandra (L.) Briq. accessions from Africa and Asia

BackgroundSpider plant [Gynandropsis gynandra (L.) Briq.], an economically promising African leafy vegetable, characterized for leaf yield components and nutritive quality, exhibits poor seed germination that hinders a wider expansion of the crop in urban and periurban horticultural systems. So far, there is little information pertaining to seed morphological traits and mineral elements content that may be associated with higher seed germination. This research investigated the hypothesis that spider plants from different geographical areas exhibited differences in seed mineral composition, morphological traits, and germination capacity. To this end, twenty-nine accessions of Gynandropsis gynandra from West and East-Southern Africa, and Asia were screened for variation in seed size (area, perimeter, length, width), 10-seed weight, mean germination time, germination percentage and mineral content variations. The scanning electron microscopy (SEM), light microscopy and energy dispersive spectroscopy (EDS) solution were used to study seed morphology and mineral composition.ResultsWe show for the first time the external and internal structure of the seeds of Gynandropsis gynandra and measured eight mineral elements, including carbon (C), oxygen (O), magnesium (Mg), aluminium (Al), phosphorus (P), sulphur (S), potassium (K) and calcium (Ca). The accessions differed significantly (p < 0.001) with respect to seed size (area, perimeter, length, width), 10-seed weight, mean germination time and germination percentage. The hierarchical cluster analysis based on fourteen variables grouped the accessions into three distinct clusters, partially dependent on their geographical origin. Asian accessions exhibited smaller seeds and recorded higher values in terms of germination percentage. West African accessions had bigger seeds but with lower germination percentage. Variation in minerals such as potassium, carbon, and calcium content showed different patterns according to geographical origins.ConclusionSmaller seeds in G. gynandra exhibited better germination capacity. The Asian germplasm is a potential source of cultivars with a higher germination percentage for improving seed quality in the species.

Tuzluluk Stresi altında Lathyrus sativus L.'nin Çimlenme ve Büyümesini İyileştirmede, Salisilik Asit ile Tohum Priming Uygulaması

Increasing the ability of crops to maintain growth and productivity under saline conditions is of paramount importance. The effect of salicylic acid (SA) priming on germination and physiological traits of Lathyrus sativus under salinity stress was studied in a factorial experiment based on a completely randomized design. The experimental treatments composed of SA at three levels (0, 0.1, and 0.2 mM) and NaCl salinity at three levels (0, 50, and 100 mM). The effect of salinity level and SA priming was significant on all recorded factors, except from final germination percentage. As salinity level increased, all germination and physiological traits declined compared with control, whereas the mean germination time and percentage of cell death were increased. Moreover, as salinity was intensified, the Hill reaction was decreased significantly. Salinity exhibited the strongest effects at NaCl rate of 100 mM. Seed priming with SA increased germination speed index, reduced mean germination time, and increased leaf relative water content, seedling fresh and dry weight compared with plants from non-primed seeds. Seedling vigor index was increased by 23.4% in primed seeds with 0.2 mM SA. SA priming especially at 0.2 mM rate increased the Hill reaction rate and reduced percentage of cell death. SA priming could be regarded as a practical approach to improve germination traits, seedling growth, and physiological traits of Lathyrus sativus L. under salinity stress conditions.

Effect of environmental factors on the germination of Megathyrsus maximus: an invasive weed in sugarcane in Argentina

Abstract Background: Megathyrsus maximus (Jacq.) is a perennial weed that affects many crops. In Argentina, sugarcane is the most affected. Objective: Study effective techniques to break dormancy and the effect of environmental factors on the germination of this weed. Methods: Experiments were carried out in cabinet incubators twice, with five replicates per treatment. The experimental unit was made up for 50 seeds. Results: Seed dormancy was strongly associated with the presence of glumes. Manual extractions of glumes and immersion in sulphuric acid were the most effective techniques for breaking dormancy. Megathyrsus maximus did not depend on light to germinate, and it did so both under a 12 h-light-dark photoperiod and in complete darkness, with maximum mean germination percentages of 73 and 76%, respectively. Mean germination percentage (G) and coefficient of germination (CG: number of germinated seeds per day) showed that this weed responded to a wide range of temperatures, the optimal varied between 25 and 35 °C. Both mean germination percentages and CG decreased as osmotic potential became increasingly negative (0 MPa to -0.6 MPa), and as sodium chloride solution concentrations increased (10 to 130 mmol L-1). No germination was observed at -0.8 MPa and with a 150 mmol L-1 sodium chloride solution. Conclusions: The optimal germination conditions for M. maximus can be found in central sugarcane areas in Argentina, since soils are in ideal conditions and are kept under irrigation. In marginal areas, M. maximus germination would depend on rainfall and certain sodium chloride concentrations in the soil.

The Effect of Seed Source and Pre-sowing Treatment on Germination of Canarium schweinfurthii [Engl] Seeds

This study examined the effect of seed source and pre-sowing treatment on germination of Canarium schweinfurthii [Engl] seeds. The seeds were sourced from Unubi in Anambra state (T1) and Jos in Plateau state (T2) in Nigeria. The experiment was conducted at the University of Benin and lasted for 14 weeks. It was laid out in a completely randomized design (CRD) pattern using 2x7 factorial combinations of 2 sources and 7 pre-sowing treatments.&#x0D; The pre-sowing treatments were complete removal of seed coat (CR), partial cracking (PC), burning under dry grass (BG), 70% H2S04 (7H), 80% H2S04 (8H), 3 days (72 hours) soaking in water (SW) and control (CT). Germination parameters investigated were days to germination, germination percentage, germination energy, germination period and germination value. Data collected were subjected to Analysis of variance (ANOVA) at 5% significance and significant means were separated using LSD. There was no significant difference in the mean days to germination (20.7 days in T1 and 21 days for T2) and mean germination percentages (31.14% in T1 and 31.71% for T2) of the sources. The treatments days to germination were significantly different with CR being the first to germinate (12 days) while 7H germinated last (41 days). There was significant difference in the mean germination period (31.71 days in T1 and 23.57 days for T2), germination energy (1.24 in T1 and 2.38 for T2) and germination values (0.3 in T1 and 0.54 for T2) in the investigated sources, while the mean germination percentages of the pre-sowing treatments irrespective of source were significantly different. Treatments BG had the best mean germination percentage followed by treatment SW and CT while 8H had the poorest.&#x0D; It is therefore recommended that treatment BG is the best followed by SW for increase in germination percentage. But where seedlings are needed in little quantity within a short time, treatments CR and PC are recommended. Acid treatment is unsuitable for the seeds of Canarium schweinfurthii.

Screening of Black Gram (Vigna Mungo L. Hepper) Varieties for Tolerance to Salinity

Salinity is one of the most important abiotic stress that affects the yield in most of the crops under cultivation. The area under black gram (Vigna mungo L. Hepper) is decreasing in recent years due to soil salinity problem. Thirteen black gram genotypes viz., VBN1, VBN2, VBN3, VBN(Bg) 4, VBN(Bg ) 5, VBN(Bg) 6, VBN 7 and VBN 8, VBG 12-034, VBG 12-062, VBG 12-110, VBG 12-111, VBG 13-003 and VBG 14-016 were screened under three EC level (4.0 EC, 11.0 EC and 16.0 EC) and compared with 0.0 EC (control). The mean germination percentage of all the thirteen genotypes studied illustrated reduced level of germination percentage with increasing salinity level. At the highest salinity level (16.0 EC) the germination percentage was significantly affected compared to 4.0 EC and 11.0 EC. The grand mean of plumule length was more at 4.0 EC and was reduced to half (16.0 EC) as compared to control. The root grew longer at 11.0 EC (4.91 cm) as compared to 4.0 EC (4.83 cm) and 0.0 EC (3.02 cm), where ever showed drastic reduction at 16.0 EC (1.92 cm). The grand mean value of dry matter weight increased concomitantly with salinity. The radical length had positive and significant correlation with dry matter weight at 11.0 EC (0.657) where as positive and non-significant correlation with 4.0 and 16.0 EC suggested that radicle length is the most useful parameter to select salinity tolerant black gram genotypes. Based on grand mean performance of the thirteen genotypes evaluated, the genotype VBG-14-016 followed by Vamban 4, Vamban 8 and VBG-12-062 outperformed than all other genotypes, while VBG-13-003 was highly susceptible followed by VBG-12-034.

Seed germination responses to seasonal temperature and drought stress are species-specific but not related to seed size in a desert steppe: Implications for effect of climate change on community structure.

Investigating how seed germination of multiple species in an ecosystem responds to environmental conditions is crucial for understanding the mechanisms for community structure and biodiversity maintenance. However, knowledge of seed germination response of species to environmental conditions is still scarce at the community level. We hypothesized that responses of seed germination to environmental conditions differ among species at the community level, and that germination response is not correlated with seed size. To test this hypothesis, we determined the response of seed germination of 20 common species in the Siziwang Desert Steppe, China, to seasonal temperature regimes (representing April, May, June, and July) and drought stress (0, −0.003, −0.027, −0.155, and −0.87 MPa). Seed germination percentage increased with increasing temperature regime, but Allium ramosum, Allium tenuissimum, Artemisia annua, Artemisia mongolica, Artemisia scoparia, Artemisia sieversiana, Bassia dasyphylla, Kochia prastrata, and Neopallasia pectinata germinated to >60% in the lowest temperature regime (April). Germination decreased with increasing water stress, but Allium ramosum, Artemisia annua, Artemisia scoparia, Bassia dasyphylla, Heteropappus altaicus, Kochia prastrata, Neopallasia pectinata, and Potentilla tanacetifolia germinated to near 60% at −0.87 MPa. Among these eight species, germination of six was tolerant to both temperature and water stress. Mean germination percentage in the four temperature regimes and the five water potentials was not significantly correlated with seed mass or seed area, which were highly correlated. Our results suggest that the species‐specific germination responses to environmental conditions are important in structuring the desert steppe community and have implications for predicting community structure under climate change. Thus, the predicted warmer and dryer climate will favor germination of drought‐tolerant species, resulting in altered proportions of germinants of different species and subsequently change in community composition of the desert steppe.

Physiological maturity of Solanum sisymbriifolium seeds

The objective of this work was to evaluate the physical and physiological quality of juá seeds (Solanum sisymbriifolium Lam.), in five maturation stages, treated with three concentrations of GA3 and submitted to the cold test. The biometric characteristics of the fruits, thousand mass and water content of the seeds, standard test and mean germination time, percentage and mean time of normal seedling formation were determined. The fruit biometry was analyzed using estimated parameters using descriptive statistics. For the other variables, a completely randomized experimental design was used in a 5 x 2 x 3 triple factorial scheme, with five maturation stages: stage 1 (green fruits), stage (2 light green fruits), stage 3 (yellow fruits), stage 4 orange fruits), and stage 5 (red-carmine fruits); seeds submitted or not to the cold test and; three concentrations of gibberellic acid (GA3), 0% (water), 0.025% (250 mg L-1) and 0.050% (500 mg L-1), with four replicates of 25 seeds each treatment. The analysis of variance showed interaction between the maturation stage of the fruits and the doses of GA3, where the maturation stages 3, 4 and 5, together with the solutions of GA3, favored the germination of the seeds. The formation of normal seedlings was higher from seeds obtained from fruits at the maturation stage 5.