SEEDLING EMERGENCE STABILITY OF BAMBARA GROUNDNUT [VIGNASUBTERRANEA L. (VERDC.)] UNDER SAVANNA AND HUMID RAIN FOREST AREAS CONDITIONS DURING TWO CROPPING SEASONS IN COTEDIVOIRE

The yield of Bambara groundnut [Vignasubterranea L. (Verdc.)] is extremely low and unpredictable. Erratic yields have been attributed, at least in part, to variable or poor field establishment due to seedling emergence. The aim of this study wasto evaluate under field conditions, the effects of genotype and environment on seedling emergence in Bambara groundnut. Field experiment was conducted with 15 landraces in Northern and Southern regions of Cote dIvoire. A randomized complete block design with five replications was used in each environment. Estimated variables included number of day for emergence (DFE), mean emergence time (MET), emergence index (EI), time to 50% emergence (T50) and seedling emergence percentage (EP). Analysis of variance revealed significant (P < 0.05) differences between genotypes, locations and the interaction genotype x location for all traits studied. Location x year x genotype interactions were only significant for DFE, EI and EP.The highest DFE and T50 and MET were observed with the genotype Ci7. The least DFE, MET and T50 were obtained with genotypes Ci1, Ci2, Ci10, Ci11, Ci12, Ci13 and Ci22. Highest seedling emergence percentage was recorded with genotype Ci15 (93.29%) in Korhogo and Ci4 in Korhogo (90.85%) and Abidjan (89.59 %). Lowest EP was observed with the genotype Ci3 (42.33%).Correlations indicated that genotype with higher emergence percentage, emerged faster (low DFE, MET, T50) and exhibited higher emergence index (EI). AMMI analysis showed that Ci1, Ci4, Ci7, Ci11, Ci14 and Ci15 were the ideal genotypes because they expressed high and stable EP.

GERMINATION OF PORANG (Amorphophalus muelleri) FROM DIFFERENT BULBIL TO VARIOUS PLANTING MEDIA

Porang plant is atubers that havevarious benefits. Porang cultivation needs intensive management through cultivation efforts which of course must be supported by the availability of seeds. Therefore, it is necessary to procure porang seeds from vegetative (tubers) and generative (stem bulbil and branch bulbil). This study aims to obtain the best growing media for porang germination from various types of bulbil. The method used in this study was a factorial randomized block design. The way of working in this research is: Preparation of Seedling Media, Preparation of planting material (Bulbil), Seeding, Maintenance (including watering and weeding). The results showed that there was no significant interaction between the planting medium and the type of bulbil, the media had no significant effect on all observed variables, while the bulbil had a significant effect on the percentage of germination growth, stem height, and number of leaves. The best type of bulbil for breeding is stem bulbil which is superior to the variables of plumule emergence time, petiole length, stem height, and number of leaves compared to branch bulbil. Meanwhile, the best growing media in porang nurseries was a mixture of 50% husk charcoal + 50% sawdust on the variables when the plumule appeared, the percentage of germination, petiole length and stem height. The appearance of bulbil from stems on a mixture of 50% husk charcoal + 50% sawdust media, namely the time of emergence of plumules (5.61 days), percentage of sprouting (86.67%), petiole length (8.72 cm), height stems (31.11 cm) and number of leaves (7.72 strands).

The effect of NAA and coconut water combination on garlic (Allium sativum L.) tissue culture

Tissue culture techniques can increase the number of garlic seedlings. The purpose of this research is to determine the effect of NAA and coconut water in increasing the number of garlic seeds. This research used a Completely Randomized Design of two factors. The treatment used is NAA with concentrations of 0 ppm, 0.5 ppm, 1 ppm, 1.5 ppm, and coconut water concentrations of 0%, 10%, 20%. The variables observed were shoot emergence time, root emergence time, number of shoots, number of roots, number of leaves, shoot height, root length, and number of plantlets. The results showed that the addition of coconut water 20% without the addition of NAA in 1 bulb can produce 3.33 planlets and the results of explant propagation in 1 bulb can produce the number of shoots as many as 15.33 shoots. Giving coconut water with concentrations of 10% and 20% can increase the number of leaves, shoot height, and some planlets. The concentration of NAA 0.5 ppm can accelerate the root emergence time on garlic explant.

Extrinsic and intrinsic factors influencing the emergence and return of Asian particolored bats Vespertilio sinensis

The circadian rhythm is an adaptive biological process, allows organisms to anticipate daily environmental changes and implement appropriate strategies. Circadian rhythms play a crucial role in the health and survival of organisms. However, little is known concerning how intrinsic and extrinsic factors affect animal daily rhythms in the field, especially in nocturnal animals. Here, we investigated the emergence and return times of Vesperilio sinensis, and also integrated environmental conditions (temperature, humidity and light intensity) and biotic factors (reproductive status and predation risk) to determine causes of variation in the activity rhythms of the bats. We found that variation in the first emergence time, the mid-emergence time, and the final return time were distinct. The results demonstrated that the emergence and return times of bats were affected by light intensity, reproductive status, and predation risk in a relatively complex pattern. Light intensity had the greatest contribution to activity rhythms. Moreover, we first investigated the effects of actual predators on the activity rhythms of bats; the results showed that the mid-emergence time of bats was earlier as predators were hunting, but the final return time was later when predators were present. This challenges the traditional view that high predation risk leads to later emergence and earlier return. Finally, our results also highlighted the importance of higher energy demands during the lactation period in bats to variation in activity rhythms. These results improve our understanding of the patterns and causes of variation in activity rhythms in bats and other nocturnal animals.

Effects of Sand Burial Depth on Xanthium Spinosum Seed Germination and Seedling Growth

different sand burial depths on seed germination, seedling emergence, growth and biomass allocation were studied to provide a scientific basis for further control of X. spinosum. Six sand burial depths (1, 2, 3, 5, 7 and 9 cm) were established to explore the response of X. spinosum seed germination and seedling growth to sand burial. The first emergence time, peak emergence time, emergence rate, seedling growth height, biomass and biomass distribution of X. spinosum seeds had significant effects at different sand burial depths (P < 0.05). The X. spinosum seeds had the highest emergence rate (71.5%) at 1 cm sand burial and the maximum seedling height (7.1 cm). As sand burial depth increased, the emergence rate and seedling height gradually decreased, and the emergence rate (12.25%) and seedling height (2.9 cm) were lowest at 9 cm sand burial. The root length at 9 cm depth (13.6 cm) was significantly higher than that at other sand depths (P < 0.05). The sand burial depth affected the biomass accumulation and distribution of X. spinosum. As sand burial depth increased, the root biomass and rhizome ratio increased, and the most deeply buried seedlings allocated more biomass for root growth. The optimal sand burial depth for seed germination and seedling growth of X. spinosum was 1–3 cm, and high burial depth (5–9 cm) was not conducive to the germination and growth of X. spinosum seedlings. For prevention and control of X. spinosum, we suggest deeply ploughing crops before sowing to ensure X. spinosum seeds are ploughed into a deep soil layer.

The importance of individual variation for the interpretation of behavioural studies: ethanol effects vary with basal activity level in zebrafish larvae

Standardization and reduction of variation is key to behavioural screening of animal models in toxicological and pharmacological studies. However, individual variation in behavioural and physiological phenotypes remains in each laboratory population and can undermine the understanding of toxicological and pharmaceutical effects and their underlying mechanisms. Here, we used zebrafish (ABTL-strain) larvae to explore individual consistency in activity level and emergence time, across subsequent days of early development (6–8 dpf). We also explored the correlation between these two behavioural parameters. We found inter-individual consistency over time in activity level and emergence time, but we did not find a consistent correlation between these parameters. Subsequently, we investigated the impact of variation in activity level on the effect of a 1% ethanol treatment, suitable for our proof-of-concept case study about whether impact from pharmacological treatments might be affected by inter-individual variation in basal locomotion. The inter-individual consistency over time in activity level did not persist in this test. This was due to the velocity change from before to after exposure, which turned out to be a dynamic individual trait related to basal activity level: low-activity individuals raised their swimming velocity, while high-activity individuals slowed down, yielding diametrically opposite response patterns to ethanol exposure. We therefore argue that inter-individual consistency in basal activity level, already from 6 dpf, is an important factor to take into account and provides a practical measure to improve the power of statistical analyses and the scope for data interpretation from behavioural screening studies.

Factors affecting the fitness of an entomopathogenic nematode (Heterorhabditis bacteriophora SUP strain) for use in biocontrol in a horticultural area of Argentina

Summary The optimum conditions for storage, infectivity and multiplication of the nematode Heterorhabditis bacteriophora SUP strain, isolated from horticultural soils in Argentina, were determined for later use in biocontrol. This strain was able to kill Tenebrio molitor larvae (over 90%) at 16 and 25°C, after 7 and 4 days, respectively, with mortality being significantly higher at 25°C. No infectivity was reported at 4 and 11°C. Higher concentrations (over 150 infective juveniles (IJ) insect−1) produced higher percentages of mortality. However, increasing inoculum density reduced offspring production and increased emergence time. Storage density between 2500 and 7500 IJ ml−1 had no effect on survival of IJ. Survival of IJ maintained at 4 and 16°C was around 80% after 4 weeks storage and 30% after 32 weeks. However, at 25°C, a 60% IJ survival was observed at 4 weeks, decreasing to around 10% after 16 weeks and with no survival at 24 weeks. An overall significant decrease in virulence was observed after 90 and 120 days of storage but this was more pronounced at a storage temperature of 4°C than at 16 and 25°C. IJ stored at 4°C had reduced virulence after 90 and 120 days, but not after 60 days. This study provides useful information about some fundamental environmental conditions influencing important nematode traits of the species H. bacteriophora.

EFFECT OF MAIZE SEEDS SOAKING WITH ACIDS OF ASCORBIC, CITRIC AND HUMIC ON FIELD EMERGENCE

A field experiment was conducted during two spring seasons in 2019 and 2020 to achieve rapid, uniform, and high ratio of field emergence of maize seeds (cv. Baghdad3). Randomize complete block design was used with three replications. Seeds were soaked in acids of ascorbic and citric (100 mg l-1) and humic (1 ml l-1) for 18 hours, as well as control treatment (seeds soaking in distilled water only). The results showed the significant superiority of soaking treatment in humic acid, which gave averages of field emergence properties in both seasons as follows: last day of field emergence (12.6 and 12.9 days), difference between first and last day of field emergence (4.8 and 4.9 days), ratio of field emergence at first count (49.5 and 55.5%), ratio of field emergence at final count (93.2 and 93.2%), daily average of field emergence (7.8 and 7.8 days), average of field emergence time (9.0 and 8.8 days) and index of field emergence average (10.5 and 10.7 days). It can be concluded that seeds soaking in humic acid improved properties of emergence and seedlings; therefore it can be recommended to soak maize seeds in humic acid (1 ml l-1) for 18 hours when planting in the spring season.

Parasitism and Suitability of Aprostocetus brevipedicellus on Chinese Oak Silkworm, Antheraea pernyi, a Dominant Factitious Host

Aprostocetus brevipedicellus, a eulophid gregarious egg parasitoid of lepidopterous pests, is a potential biological control agent for the control of many forest pests. A dominant factitious host, Antheraea pernyi, has been widely used for mass rearing several parasitoids in China. However, whether A. pernyi eggs are suitable for A. brevipedicellus rearing remains unclear. Here we evaluated A. brevipedicellus parasitism and fitness of their offspring on A. pernyi eggs with five different treatments, including manually-extracted, unfertilized and washed eggs (MUW), naturally-laid, unfertilized and washed eggs (NUW), naturally-laid, unfertilized, and unwashed (NUUW) eggs, naturally-laid, fertilized and washed eggs (NFW), and naturally-laid, fertilized and unwashed eggs (NFUW). The results showed that A. brevipedicellus could parasitize host eggs in all treatments but significantly preferred MUW eggs to other treatments. Moreover, A. brevipedicellus preferred unfertilized eggs to fertilized eggs and parasitized more washed eggs than unwashed. The pre-emergence time of parasitoid offspring emerging from fertilized eggs was shorter than that from unfertilized eggs. More parasitoid offspring emerged from unwashed eggs than that from washed eggs. The offspring emergence rate was high (>95%) and also female-biased (>85%) among all egg treatments. The egg load of female parasitoid offspring emerging from MUW and NUW eggs was 30–60% higher than the remaining treatments. Overall, MUW eggs of A. pernyi are the most suitable for the mass production of A. brevipedicellus.