Difference In Germination Percentage Research Articles

Seed morphology characterization and salinity effects on two popular rice (Oryza sativa L.) varieties of Nagaland

Salinity is one of the significant problems in rice production as it limits its growth and development. Salinity can occur through natural processes due to weathering and human intervention, such as irrigation. The present study reports two different rice varieties, 'Makrilha' and 'Thevur' which are categorized as very long (< 7.50 mm) and slender in shape (< 3.0 mm) and subjected to different salt treatments (0 mM, 100 mM, 200 mM, and 300 mM NaCl solutions) and their germination responses, such as germination percentage (GP), germination index (GI), mean germination time (MGT), vigor index (VI), root and shoot length. The study concluded that Makrilha has a higher GP (88.33%) as compared to Thevur (63%) at 200 mM NaCl solution. Both the rice showed 100% germination in the control 0 mM and 100 mM salt solutions, and no germination was recorded in the 300 mM NaCl solution. GI was recorded at its maximum in Makrilha as compared to Thevur. MGT and VI were more concentrated in Thevur than Makrilha. There was a significant difference in GI, VI, root, and shoot length (P < 0.05) as salinity increased for both rices. There was no significant difference in GP (P = 0.122) and MGT (P = 0.088). The study also found a positive correlation between GI and GP. MGT is negatively correlated with GP and GI. VI is positively correlated with GP, and GI is negatively correlated with MGT. Root and shoot length are positively correlated with GP, GI, and VI but negatively correlated with MGT for both rice varieties. The rice root and shoot length are affected as salt concentration increases and are statistically significant (root P = 0.012, shoot P = 0.001). Salt is used to control weeds in almost every part of Nagaland. Thus, the effect of salt applications needs to be studied in rice. Based on the data obtained for germination parameters such as GP, GI, VI, MGT, root and shoot length, 'Makrilha' tends to show more tolerance towards salinity as compared to 'Thevur' under controlled environmental conditions. Thus, this study can provide insight into selecting rice with a higher salt tolerance for cultivation.

Seed Germination and Seed Vigour Induction through Foliar Application of Plant Growth Regulators and Nutrients under Drought Stress in Chickpea (Cicer arietinum L.)

Chickpea cultivation in rainfed regions, such as Madhya Pradesh, faces challenges due to water stress, impacting crop yield and quality. The study conducted assesses the impact of foliar spray with plant growth regulators and nutrients on the germination percentage, seedling length, and seed vigour indices of chickpea varieties (JG 36 and JG 14) under water deficit conditions. Cytokinin analogues, known for breaking dormancy, and other growth regulators and nutrients were applied during the flowering stage. The results revealed significant differences in germination percentage, seedling length, seed vigour index I, and seed vigour index II among irrigation levels, varieties, and foliar spray of plant growth regulators and nutrients. Under different irrigation levels, D1 (Irrigation at 30 DAS and at flower initiation) recorded the highest germination percentage (97.24%), seedling length (31.41 cm), seed vigour index I (3054.81), and seed vigour index II (52.77) compared to control D2 (Drought stress at Flowering up to physiological maturity). JG 14 (V1) performed well, achieving the highest germination percentage of 96.99%. Among the treatments, foliar application of Benzyladenine (BA) at 40 ppm (T3) resulted in the highest germination percentage (98.17%) and seed vigour index II (60.33), whereas T8 (BA 40ppm + ZnSO4 1%) exhibited the highest seedling length (31.83 cm) and seed vigour index I (3099.85). This study demonstrates that foliar spray with plant growth regulators and nutrients, particularly Benzyladenine at 40 ppm, significantly improved germination percentage, seedling length, and seed vigour index, offering potential solutions for enhancing chickpea productivity under water deficit conditions.

Germination ecology and seedling growth of invasive Ageratum species and allied native Adenostemma lavenia

AbstractThe success of invasive plants can be better understood by comparing their traits with closely related native species. This study compared germination ecology and seedling growth of invasive Ageratum houstonianum and Ageratum conyzoides with co‐occurring and allied native Adenostemma lavenia. Seeds were germinated under a different light (12 h photoperiod/complete dark), temperatures (low: 25°C/15°C day/night, and high: 30°C/20°C), and different levels of water stress (−0.1, −0.25, −0.5, −0.75, and −1 MPa). Seedlings were grown to determine biomass allocation, relative growth rate (RGR), plant height, and number of leaves. The seed mass and size of native A. lavenia were higher than those of invasive species. Seeds of all species were positively photoblastic. At low temperature and in all levels of water stress, all measured parameters except mean germination time were the highest in A. houstonianum. However, at high temperature, there was no significant difference in germination percentage between A. houstonianum and A. lavenia. No germination of A. conyzoides and A. lavenia was recorded beyond −0.5 MPa water potential, but seeds of A. houstonianum germinated up to −0.75 MPa. A. houstonianum had higher root mass fraction, root‐to‐shoot ratio, and number of leaves than the other two species. Stem mass fraction and the height of seedling were highest in A. conyzoides. The RGR was 1.6 times higher in invasive Ageratum species than the native species; it was slightly higher in A. houstonianum than in A. conyzoides. Overall, the results suggest that germination traits and seedling growth performance can be used as predictors of a species' invasiveness.

Oryzalin delays germination and induces putative polyploidy plants in local North Sumatra garlic (Allium sativum L.)

Oryzalin is anti-mitotic herbicide. It has been used to induce polyploidy in several plants. The aim of this study was to determine the effectiveness of oryzalin in inducing polyploids and its physiological effects on North Sumatran local garlic (Allium sativum L.) germination. This study used a factorial completely randomized block design (CRBD). The first factor was oryzalin concentration with 5 treatment levels, namely R1 (0 µM), R2 (100 µM), R3(200 µM), R4 (300 µM) and R5 (400 µM). The second was soaking duration, consisting of H1 (24 hours) and H2 (48 hours). The parameters observed were percentage of germination and sprout morphology, observed at 1 and 3 weeks after treatment. The collected data were processed using ANOVA and if they were significantly different, it was continued with the DMRT test at a 5% significant level. The results showed that oryzalin suppressed garlic germination in the first week, but the effect disappeared and there was no significant difference in germination percentage at 3 weeks after soaking. Treatment with 200 µM for 48 hours and 400 µM oryzalin for 24 hours induced putative polyploidy garlic, the morphological shoot showed higher and thicker leaves than control.

Physiological Potential of Seeds of Handroanthus spongiosus (Rizzini) S. Grose (Bignoniaceae) Determined by the Tetrazolium Test

Tetrazolium test (TZT) can quickly evaluate in detail the viability and vigor of seeds. This study aimed to determine the optimal conditions for conducting the TZT on seeds of Handroanthus spongiosus. For this purpose, seeds from three lots were pre-soaked in water for 16 h, followed by extraction of the tegument and immersion in tetrazolium salt solutions at different concentrations (0.01–0.1%), for increasing periods (1–4 h) and at 30 °C in the dark. The experimental design was completely randomized with a 4 × 4 factorial scheme with 25 seeds per repetition. We applied generalized linear models and the Tukey test for pairwise comparisons of the means at 5% probability. The viability/vigor results were compared with data obtained from the germination test at 25 °C using a subsample of seeds from the same lots. The time (1 h to 4 h) of immersion of the seeds in tetrazolium salt solutions did not cause a clear coloration difference. The seeds subjected to all treatment concentrations for 3 h presented average viability greater than 60%, with no difference in germination percentage. The TZT at 0.01% tetrazolium salt solution for 3 h was most efficient in assessing the viability of the Handroanthus spongiosus seeds.

REPRODUCTIVE GROWTH RESPONSE OF SWEET PEPPER (Capsicum annum L) IN SOIL AMENDED WITH FALSE YAM (Icacina oliviformis) TUBER BIOCHAR

Biochar, carbon rich stable solid material, is used mostly for soil amendment. The main objective of this study was to assess false yam tuber biochar performance or effect on the vegetative growth of pepper. Pepper seeds were obtained at Wumpini agrochemical shop in Tamale which were sown, and growth parameters were assessed (germination percentage, plant height, number of leaves and leaf area index). The soil was amended with biochar produced from false yam tuber. The experiment consisted of seven treatments (T1, T2, T3, T4, T5, T6, T0) replicated three times including the control (soil only). The soil and biochar mixture were done in two different levels (6 g/pot and 12 g/pot) each at three different times (four weeks before planting (4WBP), two weeks before planting (2WBP) and at planting (DOP)) with control as soil only. Results obtained indicated that there were no significant differences in germination percentage among the treatments both at one week and two weeks after planting. The highest growth performance (plant height, number of leaves and leaf area index) was recorded in the control. The least growth performance was recorded in treatment T1 (6 g of biochar applied at 4 weeks before planting (4WBP)). The application rate of false yam tuber biochar (6 g/pot and 12 g/pot) as soil amendment might not be the right amendment for sweet pepper production.

Effects of γ-radiation on chickpea (Cicer arietinum) varieties and their tolerance to salinity stress

Chickpea (Cicer arietinum L.) is a bisexual and self-pollinated legume. It improves the soil fertility through its natural ability to fix atmospheric nitrogen with its symbiotic bacteria. Salinity is one of the most important abiotic stress factors affecting plant growth. γ-radiation is a very effective tool for inducing mutations in many plants. This study evaluated the γ-radiation effect on germination, cell division and plant growth of first-generation plants. Seeds of seven chickpea varieties were irradiated with γ-radiation doses ranging between 50 Gy and 600 Gy. Non-significant differences in germination percentage were recorded for seeds exposed to 50 Gy, 100 Gy, and 200 Gy of γ-radiation in comparison to the corresponding controls except ILC 484. The mitotic index (MI) of root cells increased at the low doses of 50 Gy, 100 Gy and 200 Gy comparing and reduced at the higher doses in all chickpea varieties to the control. All doses of γ-radiation induced a variable range of chromosomal abnormalities; the most common were bridges, laggard chromosomes, stickiness at metaphase, chromosome breaks, micronuclei and binucleate cells. The 300 Gy to 600 Gy doses induced degradation of nuclear membranes. The salinity treatments at 25 mM NaCl and 60 mM NaCl reduced seedling’s growth of all cultivars. The dose of 100 Gy alleviated the impact of salinity at a concentration of 25 mM NaCl for all varieties, except FLIP 84-188 and FLIP 97-263. The 60 mM NaCl treatment significantly reduced early growth of all cultivars and its effect was not alleviated by the γ-radiation.

Mucilage affects seed water imbibition and germination time of subtropical monsoonal forbs

The role of seed mucilage in the moist environments of monsoonal subtropics is poorly understood. We studied germination of six forb species from subtropical monsoonal China. Mucilage presence had little to no effect on germination percentage (G%), except for a significant decline for the large-seeded Prunella vulgaris. Dark treatments reduced G% for all species, while the combination of mucilage removal and high temperatures delayed the mean germination time (MGT). Seed fresh mass was negatively correlated with G%, but only for intact seeds incubated at 12/12 hours of 25/35 °C. The MGT of de-mucilaged seeds varied with seed shape index, also under the warmer temperature regime. Temperature and light are fundamental to drive germination processes, and the presence of mucilage influences MGT of subtropical monsoonal species. Presence or absence of mucilage had little to no difference in germination percentage, but can be important to drive germination timing, also promoting water uptake and seed adhesion to soil.

Combining ability and heterosis in Sorgum (Sorghum bicolor L.)

For the sustainable improvement of sorghum (Sorghum bicolor L.), local genotypes were conventionally crossed in East Java, Indonesia to determine a) the crossing success of different genotypes, b) germination percentage and seed setting traits, and c) the combining ability and heterotic effect of sorghum parental genotypes and their F1 diallel hybrids. Three sorghum genotypes (‘Lamongan-1’, ‘Tulungagung-2’, and ‘Jombang’) from the local germplasm were collected from various regions in East Java, Indonesia, and were crossed in a complete diallel design. The experiment was carried out in a randomized complete block design with four replications during 2018–2019 at the Agrotechnology Laboratory, Faculty of Agriculture, University of Muhammadiyah, Malang, Indonesia. Results showed that the parental genotypes and their F1 hybrids exhibited significant differences in seed weight and seed diameter and nonsignificant differences in germination percentage and seed setting. The parental genotype ‘Tulungagung-2’ and its hybrids ‘Jombang’ × ‘Tulungagung-2’, ‘Tulungagung-2’ × ‘Lamongan-1’, and ‘Jombang’ × ‘Tulungagung-2’ presented the highest germination percentages, seed setting, seed weights, and seed diameters. The genotype ‘Tulungagung-2’ had the highest general combining ability and was identified as a good general paternal and maternal parent for the production of promising F1 hybrids. The hybrid ‘Jombang’ × ‘Lamongan-1’ had the highest specific combining ability for all of the characters and was recognized as a promising F1 hybrid for improving sorghum yield. Cluster analysis divided all of the parental genotypes and their F1 hybrids into two large groups with a similarity of 13.13%.

Presence and seed transmission of phytoplasmas in tomato fields in Italy

Tomatoes are the second most consumed vegetable, quite often severely affected by phytoplasma-associated diseases worldwide. The identification and confirmation that the phytoplasmas associated with the disease in Southern Italy are also transmitted through seeds was achieved. DNA extractions from mother plants collected in 2020 and 2021 and the seedlings from these plants, tested at different times, allowed the detection of phytoplasmas in both mother plants and seedlings grown under an insect-proof greenhouse. Phytoplasmas enclosed in groups 16SrX-B (‘Candidatus Phytoplasma prunorum’) and 16SrV-A (‘Ca. P. ulmi’) were identified in 2020 samples, and the same phytoplasma groups were identified in the seedlings. Phytoplasmas enclosed in groups 16SrI and 16SrXII were identified in mother plants collected in 2021 and were also identified in the seedlings. Moreover, a difference in germination percentage was observed. The 16SrXII-A group phytoplasmas detected in the mother plants and were identified as variants St5 for the stamp gene, tuf-b1 for the tuf gene and Vm44 for the vmp1 gene. This research is a significant confirmation of previous laboratory results on transmission of phytoplasmas through seeds from several diseased plant species. The epidemiological role of phytoplasma seed transmission is an essential knowledge for efficient management strategy planning for a seed production aimed at reducing the impact of phytoplasma-associated diseases in horticultural relevant crops such as tomatoes.

In vivo and in vitro performance studies on groundnut (Acharis hypogea L.) genotypes for yellow witchweed (Alectra vogelii Benth.) resistance

Witchweed (Alectra vogelii Benth.) is a legume parasitic weed that causes severe yield reduction of groundnut (Acharis hypogea L.) in Africa. The study was conducted to screen and identify Alectra vogelii resistant and/or tolerant groundnut genotypes evaluated under both laboratory and glasshouse at the University of Zimbabwe during 2018/19 cropping season. The findings of the lab agar-gel screening experiment revealed significant differences in germination percentage and germination distance between genotypes. Significant genotype x A. vogelii infestation interaction on plant biomass, root to shoot ratio and shelled grain yield were observed. Alectra vogelii parasitism significantly reduced plant biomass and shelled grain yield across groundnut genotypes. Conversely, genotypes like Njiva, Ilanda and Guinea fowl did not support any haustorial attachment, and had the highest shelled grain yield under all A. vogelii infestation levels. Assessment of A. vogelii tolerance based on groundnut growth, physiological and yield related parameters revealed that the groundnut genotypes Njiva, Ilanda and Guinea fowl tolerated A. vogelii infection, whereas Dendera, Jessa, Nyanda and Tern could be susceptible. Field studies are expected to validate the initiative of breeding with farmers of tolerance groundnut genotypes to A. vogelii infection.

Seed dispersal by the brown bear in a mixed temperate forest: fruit type matters

The brown bear (Ursus arctos L.) is an omnivorous large mammal that has an essential function in many ecosystems as a seed disperser. We studied the brown bear’s role as a seed dispersal agent in a mixed temperate forest in northern Anatolia, Turkey. We collected 197 fecal samples from the field during the brown bear’s active period for two consecutive years. We extracted seeds of 34 plant taxa from fecal samples. Among these taxa, 29 had intact seeds, whereas seeds of 5 were found to be entirely or mostly physically damaged. Damaged seeds belonged to fruits of acorn, capsule, nut, and drupe-like nut types, while no or few seeds from fleshy fruits such as berry, drupe, pome, and rosehip types had damage. Seeds from pome type fruits of Malus sylvestris and Pyrus elaeagnifolia had a higher germination percentage in feces than in the control (fresh seeds collected from the field), but that was quite the opposite in berries of Lonicera caucasica and Vaccinium arctostaphylos. No difference in germination percentage was found between feces and control groups in seeds from rosehips. Our results reveal that seeds of several species found in the study area are dispersed by the brown bear, especially those with fleshy fruits (e.g., Rosaceae members). In this study, we established the role of the brown bear as a seed dispersal agent in northern Anatolian mixed temperate forests. Our study suggests that fruit type is a determinant of the success of endozoochorous seed dispersal by the brown bear.

Protection of Italian ryegrass (Lolium multiflorum L.) seedlings from salinity stress following seed priming with L-methionine and casein hydrolysate

AbstractSeed priming with water (hydropriming or HP) has been shown to be beneficial for seed germination and plant growth. However, there is little information on the effects of seed priming with amino acids and casein hydrolysate (CH) compared with HP, particularly in relation to early post-germinative seedling growth under salinity stress. In this study, Italian ryegrass seeds (Lolium multiflorum L.) were primed with 1 mM of each of the 20 protein amino acids and CH (200 mg l−1) before they were germinated in 0, 60 and 90 mM NaCl in Petri dishes for 4 d in darkness. Germination percentage (GP), radicle length (RL) and peroxidase (POD) activity in the root of 4-d-old Italian ryegrass seedlings were investigated. Generally, when the seeds were germinated in 0, 60 and 90 mM NaCl, there was no significant difference in GP of seeds among various priming treatments, except that a higher GP was observed in seeds of HP treatment compared with the non-primed seeds when incubated in 60 mM NaCl. When incubated in 60 and 90 mM NaCl, seedlings from seeds primed with L-methionine or CH exhibited greater RL (greater protection against salinity stress) and higher root POD activity than those from non-primed and hydro-primed seeds. Under salinity stress, there were higher levels of malondialdehyde (MDA) in the root of 4-d-old Italian ryegrass seedlings, a marker of oxidative stress, but seed priming with CH was effective in reducing the salinity-triggered increase in MDA content. These results suggest that priming with L-methionine or CH would be better than HP for the protection of seedling root growth under salinity stress and might be associated with enhanced antioxidative defence against salinity-induced oxidative stress.

Effect of seed size on germination in three species from arid Arabian deserts

In many species, seeds with different sizes show diverse responses in their requirements for temperature and light for optimal germination. In this study, the effect of seed size (i.e., small and large) on germination was tested in seeds of Brassica tournefortii Gouan, Lotus garcinii DC., and Salvadora persica L. from arid Arabian Desert habitats. The mean seed size of all three study species differs significantly between small and large-sized seeds. Differences were observed in seed germination between large and small seeds of B. tournefortii and L. garcinii. We found that the large seeds of B. tournefortii and L. garcinii showed a higher germination percentage at all tested temperatures than that displayed by the small seeds. However, both small and large seeds of S. persica germinated equally (100%) well under all tested incubation conditions. Our results show significant differences in germination percentage between the small and large seeds of B. tournefortii at 25/35 °C under a 12 h light regime. However, seeds of L. garcinii showed a significant difference in germination percentage at low temperatures (15/25 °C) under a 12 h light regime.

Effect of polyhouse conditions on germination and seedling growth of Morus alba var. Kokuso

The present investigation entitled “Effect of Polyhouse conditions on germination and seedling growth of Morus alba var. Kokuso”was carried out at Faculty of Forestry, Benihama, Ganderbal J&K.The seedling nursery of Morus specieswas raised in polyhouse as well as under field conditions. Studies conducted on nursery raising of Morus alba varietyKokuso revealed that raising of seedlings under polyhouse conditions were much superior than those grown in field. The performance of seedling nursery in both cases was assessed in terms of various parameters and then put to statistical analysis revealed that there was a highly significant differences in germination percentage, survival percentage, plant height, collar diameter and root length. Germination percentage (88.66%), survival percentage (80.70%), average plant height (24.66 cm), average collar diameter (5.66 mm) and average root length (10.40 cm) was recorded highest in seedlings raised under polyhouse conditions while as germination percentage (67.66%), survival percentage (58.44%), average plant height (17.20 cm), average collar diameter (4.22 mm) and average root length (7.16 cm) was recorded lowest in seedlings raised in open conditions.

Effect of Different Media on Germination and Seedlings Performance of Chili Pepper (Capsicum annum)

The production of vegetable seedlings is an important business for some farmers in most parts of the world with poor media being a major constraint. An experiment was conducted to investigate the effect of different media on germination and nursery performance of chili pepper at the Department of Horticulture, Kwame Nkrumah University of science and Technology (KNUST). A Randomized Complete Block design with six treatments and three replications was used in the study. Media treatments were used either alone or in combination and they were: topsoil only, rice hull ash only, rabbit waste only, topsoil and rice hull ash (1:1), topsoil and rabbit waste (1:1) and topsoil and river sand (1:1). There were significant differences in germination percentage, seedling height, number of leaves and stem girth as function of the media treatments. The different media however did not affect days to 50% germination significantly. Comparatively, the highest and the lowest germination percentages (77.50% and 62.00%) were obtained by nursing seeds in the mixture of topsoil and rice hull ash as well as rabbit waste only respectively. In terms of growth characteristics, plant height and number of leaves were highest in seedlings nursed in topsoil and rice hull ash mixture (18.36 cm and 13.23 cm) respectively at the end of the study period. The highest stem girth was seedlings nursed in topsoil (3.129 mm) at the end of the experiment. Plants nursed in rabbit waste only had the lowest growth performance in terms of plant height (2.75 cm), number of leaves (4.50) and stem girth (1.27 mm) at the end of the experiment. Growth medium consisting of a mixture of proportion of topsoil and rice hull ash is therefore recommended for growing chili pepper seedlings since this combination improved both germination and subsequent growth as compared to the other media used in the experiment. Rice hull ash is not recommended to be used alone in raising chili pepper seedlings since it has a high pH which decreases seedling growth. Partially decomposed rabbit waste is also not suitable to be used as nursery medium because it retards seedling growth.

Effect of germination potential on storage lipids and transcriptome changes in premature developing seeds of oilseed rape (Brassica napus L.).

We provided a gene pool of moderate size for selecting or manipulating the candidate genes that favour the acquisition of seed dormancy, shedding light on the elevation of seed oil content in oilseed rape by blocking lipid degradation in developing seeds. In oilseed rape, the association between the germination potential of premature seeds and the final level of seed lipids, and the underlying mechanism, is elusive. Here, we investigated phenotypic differences in the germination percentage of premature seeds in a collection of oilseed rape cultivars. We compared the dynamic lipid accumulation between the deep-, moderate- and non-dormant genotypes and compared the transcriptomes of the seeds at 40days after pollination between multiple pairs of deep- and non-dormant genotypes. We identified a wide range of differences in germination percentage of premature seeds and the association between the germination potential and the change of fatty acid content at late stage of seed maturation. The comparisons of transcriptomes between deep- and non-dormant seeds revealed the genetic basis for the dormant difference, e.g. the different expression levels of the genes involved in gibberellic and abscisic acid biosynthesis and/or signalling, fatty acid metabolic pathways, and the structure of seed cell wall. We provided a gene pool of moderate size for selecting or manipulating the candidate genes that favour the acquisition of seed dormancy, shedding light on the elevation of seed oil content in oilseed rape by blocking lipid degradation in developing seeds.

In Vitro and In Vivo Evaluation of Sorghum (Sorghum bicolor L. Moench) Genotypes for Pre- and Post-attachment Resistance against Witchweed (Striga asiatica L. Kuntze)

Sorghum (Sorghum bicolor L. Moench) production in sub-Saharan Africa is seriously constrained by both biotic and abiotic stresses. Among the biotic stresses is witchweed (Striga spp.), a noxious parasitic weed causing major damage in cereal crops, such as sorghum. However, resistance through reduced germination stimulant production or altered germination stimulant composition provides a sustainable and most effective way for managing the parasitic weeds. Laboratory and glasshouse experiments were conducted using seven (7) sorghum genotypes to evaluate their resistance or tolerance the witch weed (Striga asiatica L. Kuntze). The first experiment was a laboratory agar gel assay arranged in a completely randomized design with six (6) replications to evaluate the effects of the seven (7) sorghum genotypes on the production of strigolactones by determining the percentage germination and the furthest germination distance of the Striga seeds. The second experiment was a seven (7) (sorghum genotypes)∗two (2) (Striga treatments) factorial glasshouse experiment conducted to evaluate the effects of Striga on sorghum growth, physiological and yield components of sorghum, Striga syndrome rating, and number of Striga per plant. The genotypes showed a significant (p<0.05) difference in germination percentage and furthest germination of Striga seeds in the agar gel assay. Genotypes SV4, Mahube, and ICSV 111 IN showed the least germination percentage and lowest germination distance, implying that these varieties either produced low strigolactones or altered their composition. In contrast, Kuyuma, Wahi, SV2, and Macia caused high Striga seed germinations and high furthest germination distances, suggesting that these sorghum genotypes were susceptible to Striga infection. The sorghum × Striga × time interactions were significant (p<0.05) on sorghum height. It was found that the heights of sorghum genotypes ICSV 111 IN and Mahube were not altered by Striga infection, but the heights of Kuyuma, Macia, SV2, SV4, and Wahi were reduced by Striga infection. The interaction of sorghum∗Striga effects was significant (p<0.05) on chlorophyll fluorescence. Striga infection did not alter the chlorophyll content of ICSV 111 IN and SV4. The sorghum∗Striga interaction effects were significant (p<0.05) on head index, leaf biomass, leaf index, root biomass, root index, plant biomass, and root : shoot ratio. Assessing Striga tolerance based on sorghum heights, chlorophyll content, and root : shoot ratio parameters, it could be concluded that the sorghum genotypes Mahube, ICSV 111 IN, and SV4 tolerated Striga infection, whereas Kuyuma and SV2 could be susceptible.

Germination of native legumes in relation to competition of neighbor seeds in Northeastern Mexico1

We explore whether percentage of seed germination and rate are affected by the presence of seeds from other species and if this is related to phylogeny. Assuming that closely related species might inhibit germination as a means to avoid competition, we tested germination in Petri dishes of seeds of one species and a combination of that one species with each of eight other species. Phylogenetic distance measured as millions of years since a common ancestor was tested for correlation with germination percentage and germination rate across all species combinations, expecting less and slower germination when closely related species were placed together. Seed germination percentage was significantly less for two species in some combinations, but this difference was very small. For two species, seed germination was up to one day slower in the presence of seeds from other species. These differences were not correlated to phylogeny. The small difference in germination percentage would probably not have an effect in field conditions. The slower time to germination could result in some seedlings starting to grow next to larger seedlings and with fewer days of moist soil.

Evaluation of pre-germination treatments on four native species of the High Andean forest

High Andean forests are strategic ecosystems with high diversity of native and endemic plants; however, these natural ecosystems are affected by agricultural expansion. Knowledge on the propagation of native plants is essential to restore these environments. This research aimed to evaluate germination in the following native species: Viburnum triphyllum Kunt. (Caprifoliaceae), Oreopanax floribundum Kunth, (Araliaceae), Weinmannia tomentosa L.f. (Cunoniaceae), and Tournefortia fuliginosa Benth. (Boraginaceae) in Botana experimental farm of Universidad de Nariño. This study was conducted between October (2016) and February (2017). For each species, an unrestricted randomized split-plot design was established. The main plot included the substrates (S), and the sub-plots included the different pre-germination treatments (PM) with three repetitions. The results showed statistically differences in germination percentage among pre-germination treatments for O. floribundum. The highest germination percentage (42%) for this species was achieved with seed imbibition for 48 hours at 22°C. Moreover, W. tomentosa showed statistical differences for S and PM, with a germination percentage of 74% with imbibition for 48 h at 22°C and sand substrate. T. fuliginosa did not show relevant differences; however, it had a germination percentage of 47%. V. triphyllum did not germinate; therefore, further evaluations of pre-germination treatments should be required.