EVALUATION OF PHYTOTOXICITY OF NATURAL MINERALS

An assessment of the phytotoxicity of natural (lime, zeolite and phosphorite) minerals and their nanostructured analogues (nanostructured lime, nanostructured water-zeolite suspension (NWZS), nanostructured water-phosphate suspension (NWPS) and a spine) has been carried out. a monocotyledonous test plant (spring wheat variety Ulyanovskaya-105) has a positive effect on all studied minerals. The length of the seedling among native minerals is stimulated by lime and phosphorite, among nanominerals - nanostructured lime and NWZS. All native minerals have a positive effect on biometric indicators, among nanostructural ones – nano-lime and NWPS. Seedling biomass is stimulated only by zeolite and NWZS. Thus, native zeolite has the best data on the length of the seedling (by 48.9 %), the length of the coleoptile (by 53.6 %) and the biomass of the seedling (by 16.1 %), and in NWZS - along the root length (by 12.8 %), root biomass (by 13.5 %) and seedling biomass (by 13.7 %). Thus, according to most indicators, the best are zeolite (among native ones) and NWZS (among nanostructured minerals).

Toward understanding the impact of nuisance algae bloom on the reduction of rice seedling emergence and establishment

California rice (Oryza sativa L.) production has been recently challenged by the early season bloom of nuisance algae. The algal community in rice is a complex of green algae (Nostoc spongiforme Agardh ex Bornet) and cyanobacteria species that could develop a thick algal mat on the surface of the water and interfere with the emergence and establishment of rice seedlings. The objective of this research was to determine the impact of algae infestation level on rice seedling emergence. A mesocosm study was conducted in 57 L tubs. Three levels of algae infestation (low, medium, and high) were produced by adding fertilizer N:P amount into the tubs including 0:0, 75:35, and 150:70 kg-1ha. Sixty rice seeds (M-206) were soaked for 24 hours and spread into tubs filled with water. Photosynthetic Active Radiation (PAR), Chlorophyll a concentration as the quantitative measure of algae, number of emerged rice seedlings, and their dry biomass were studied during the experiment. Results showed that algae infestation can directly change the amount of light received into the water. Minimum, maximum and mean percentage of PAR inside the water declined by the increase of algae infestation level. As a consequence, rice seedling emergence dropped under the high algae pressure. At very high algae infestation (i.e. chlorophyll a concentration of above 500 µg ml-1), rice seedling emergence reduced up to 90%. Furthermore, rice seedling emergence was delayed under algae infestation. When algae infestation was low, time to 50% of rice seedling emergence (t50) ranged between five and ten days, while at high algae infestation t50 ranged between twelve and twenty days. Moreover, individual rice seedling biomass reduced from one gram to 0.01 gram by the increase of algae infestation. The results from this study indicate that uncontrolled algae at the beginning of the rice-growing season could reduce rice seedling emergence, establishment, and rice stand. Given that algae infestation in field has a patchy pattern, loss of rice stand in these patches could provide empty niches for other weeds to grow.

Enhancing Teak (Tectona grandis) Seedling Growth by Rhizosphere Microbes: A Sustainable Way to Optimize Agroforestry

With its premium wood quality and resistance to pests, teak is a valuable tree species remarkably required for timber trading and agroforestry. The nursery stage of teak plantation needs critical care to warrant its long-term productivity. This study aimed to search for beneficial teak rhizosphere microbes and assess their teak-growth-promoting potentials during nursery stock preparation. Three teak rhizosphere/root-associated microbes, including two teak rhizobacteria (a nitrogen-fixing teak root endophyte-Agrobacterium sp. CGC-5 and a teak rhizosphere actinobacterium-Kitasatospora sp. TCM1-050) and an arbuscular mycorrhizal fungus (Claroideoglomus sp. PBT03), were isolated and used in this study. Both teak rhizobacteria could produce in vitro phytohormones (auxins) and catalase. With the pot-scale assessments, applying these rhizosphere microbes in the form of consortia offered better teak-growth-promoting activities than the individual applications, supported by significantly increased teak seedling biomass. Moreover, teak-growth-promoting roles of the arbuscular mycorrhizal fungus were highly dependent upon the support by other teak rhizobacteria. Based on our findings, establishing the synergistic interactions between beneficial rhizosphere microbes and teak roots was a promising sustainable strategy to enhance teak growth and development at the nursery stage and reduce chemical inputs in agroforestry.

Respons pertumbuhan bibit kelapa sawit terhadap bioherbisida saliara di pembibitan awal

AbstrakKeberadaan gulma pada pembibitan kelapa sawit dapat menurunkan kualitas bibit. Pengendalian gulma di pembibitan awal harus dilakukan secara dengan tangan (hand weeding), karena bibit dapat mati akibat aplikasi herbisida. Aplikasi bioherbisida saliara (Lantana camara) pada bibit kelapa sawit (Elaeis guineensis Jacq.) dapat menjadi alternatif pengendalian gulma yang ramah lingkungan dan mengurangi tenaga kerja. Penelitian ini dilaksanakan di Kebun Percobaan 1 Politeknik CWE, pada November 2019 sampai Februari 2020. Percobaan disusun dalam Rancangan Acak Kelompok, dengan perlakuan: kontrol (tanpa aplikasi bioherbisida), Ekstrak Lantana camara 1%, 2%, dan 3%. Setiap perlakuan diulangi sebanyak tiga kali. Hasil penelitian menunjukkan bahwa Bioherbisida Lantana camara mengandung senyawa alelokimia yaitu Saponin (2,07%), Tanin (3,28%), dan Flavonoid (1,83%). Gulma Lantana camara dapat dijadikan bahan alternatif bioherbisida pra tumbuh karena berpengaruh nyata terhadap daya tumbuh gulma. Meskipun bioherbisida menurunkan tinggi bibit pada 3 bulan setelah tanam (BST) dan diameter batang bibit pada 1 BST, namun bioherbisida tidak mempengaruhi jumlah daun, kehijauan daun, dan biomassa bibit. Bioherbisida Lantana camara dengan konsentrasi 1% menunjukkan hasil terbaik dalam menekan laju pertumbuhan gulma.Kata Kunci: Bibit, Bioherbisida, Fisiologi, Gulma, Morfologi Abstract. The presence of weeds in oil palm nurseries can reduce the quality of the seedlings. Usually, mechanical weeding by hand is needed in pre-nursery because the use of chemical treatment caused the oil palm seeeling died. Bioherbicide application of Lantana camara to oil palm seedling (Elaeis guineensis Jacq.) can be alternative weed control that is environmental friendly and reduces labor. This research conducted at Teaching Farm Politeknik CWE, from November 2019 to Februari 2020. Experiment was arranged in Randomized Block Design, with treatments are Control (without bioherbicide application), Bioherbicide Lantana camara 1%, 2% and 3%. Every treatments was repeated three times. The results showed that Lantana camara bioherbicide contained allelochemical compounds, namely saponins (2.07%), tannins (3.28%), and flavonoids (1.83%). Lantana camara weed can be used as an alternative material for pre-growing herbicides because it has a significant effect on reduced weed population. Although bioherbicides decreased seedling height at 3 months after planting (MAP) and stem diameter at 1 MAP, bioherbicides did not affect leaf number, leaf greenness, and seedling biomass. Bioherbicide Lantana camara with concentration 1% showed the best treatment for controlling weeds in oil palm pre nursery.Keywords: Bioherbicide, Morphology, Physiology, Seedlings, Weed

Heterotic quantitative trait loci analysis and genomic prediction of seedling biomass-related traits in maize triple testcross populations

Background Heterosis has been widely used in maize breeding. However, we know little about the heterotic quantitative trait loci and their roles in genomic prediction. In this study, we sought to identify heterotic quantitative trait loci for seedling biomass-related traits using triple testcross design and compare their prediction accuracies by fitting molecular markers and heterotic quantitative trait loci. Results A triple testcross population comprised of 366 genotypes was constructed by crossing each of 122 intermated B73 × Mo17 genotypes with B73, Mo17, and B73 × Mo17. The mid-parent heterosis of seedling biomass-related traits involved in leaf length, leaf width, leaf area, and seedling dry weight displayed a large range, from less than 50 to ~ 150%. Relationships between heterosis of seedling biomass-related traits showed congruency with that between performances. Based on a linkage map comprised of 1631 markers, 14 augmented additive, two augmented dominance, and three dominance × additive epistatic quantitative trait loci for heterosis of seedling biomass-related traits were identified, with each individually explaining 4.1–20.5% of the phenotypic variation. All modes of gene action, i.e., additive, partially dominant, dominant, and overdominant modes were observed. In addition, ten additive × additive and six dominance × dominance epistatic interactions were identified. By implementing the general and special combining ability model, we found that prediction accuracy ranged from 0.29 for leaf length to 0.56 for leaf width. Different number of marker analysis showed that ~ 800 markers almost capture the largest prediction accuracies. When incorporating the heterotic quantitative trait loci into the model, we did not find the significant change of prediction accuracy, with only leaf length showing the marginal improvement by 1.7%. Conclusions Our results demonstrated that the triple testcross design is suitable for detecting heterotic quantitative trait loci and evaluating the prediction accuracy. Seedling leaf width can be used as the representative trait for seedling prediction. The heterotic quantitative trait loci are not necessary for genomic prediction of seedling biomass-related traits.

Effect of Oak Tree Sawdust Fermentation Period on Peanut Seed Germination, Seedling Biomass, and Morphology

Peanut (Arachis hypogaea L.) seeds were germinated to investigate the effect of the fermentation period of oak tree sawdust on germination viability and seedling characteristics. Its germination rate, seedling weight, length, and total vigor index were assessed. The seeds were sown in oak tree sawdust fermented for 0, 30, 45, and 60 days. The germination rates of the seeds in fermented sawdust were significantly different. The seeds in the 45-day fermented sawdust produced the heaviest biomass weight (4.6 g) with the longest true leaf (1.7 cm) and hypocotyl (3.4 cm) resulting in the highest total vigor index (925.8). In contrast, seeds in 0-day fermented sawdust had the lowest total vigor index (18.3). Microbiome analysis showed that the microbial community in the sawdust changed as the fermentation progressed, indicating that the microbial community seems to affect seed germination physiology. Taken together, 45-day fermented sawdust is recommended for optimal peanut seed germination and seedling growth.