Root Dry Weight Ratio Research Articles

Genome-wide association analysis reveal candidate genes and haplotypes related to root weight in cucumber (Cucumis sativus L.).

The plant root system is critical for the absorption of water and nutrients, and have a direct influence on growth and yield. In cucumber, a globally consumed crop, the molecular mechanism of root development remains unclear, and this has implications for developing stress tolerant varieties. This study sought to determine the genetic patterns and related genes of cucumber root weight. A core cucumber germplasms population was used to do the GWAS analysis in three environments. Here, we investigated four root-weight related traits including root fresh weight (RFW), root dry weight (RDW), ratio of root dry weight to root fresh weight (RDFW) and the comprehensive evaluation index, D-value of root weight (DRW) deduced based on the above three traits for the core germplasm of the cucumber global repository. According to the D-value, we identified 21 and 16 accessions with light and heavy-root, respectively. We also found that the East Asian ecotype accessions had significantly heavier root than other three ecotypes. The genome-wide association study (GWAS) for these four traits reveals that 4 of 10 significant loci (gDRW3.1, gDRW3.2, gDRW4.1 and gDRW5.1) were repeatedly detected for at least two traits. Further haplotype and expression analysis for protein-coding genes positioned within these 4 loci between light and heavy-root accessions predicted five candidate genes (i.e., Csa3G132020 and Csa3G132520 both encoding F-box protein PP2-B1 for gDRW3.1, Csa3G629240 encoding a B-cell receptor-associated protein for gDRW3.2, Csa4G499330 encodes a GTP binding protein for gDRW4.1, and Csa5G286040 encodes a proteinase inhibitor for gDRW5.1). We conducted a systematic analysis of the root genetic basis and characteristics of cucumber core germplasms population. We detected four novel loci, which regulate the root weight in cucumber. Our study provides valuable candidate genes and haplotypes for the improvement of root system in cucumber breeding.

Germination and Seedling Properties of Lotus corniculatus L. Under Simulated Drought Stress

Drought is an important abiotic stress factor that reduces agricultural production and yield in many crops, including forage crops, in agricultural areas around the world. Lotus corniculatus L. is the agriculturally crucial perennial legume forage crop that can tolerate moderate drought. However, studies to determine the responses of L. corniculatus to drought are limited. Therefore, this study was carried out to determine the seed germination and early seedling growth properties of L. corniculatus at different PEG6000 induced-drought treatments under in vitro conditions. In order to do this, L. corniculatus (cv. ‘AC Langille’) seeds were planted in MS (Murashige and Skoog/Gamborg) medium containing 0%, 4%, and 8% (w/v) PEG6000 for 14 days. In this study, germination percentage, mean germination time, germination rate index (speed of germination), shoot and root length, root to shoot length ratio, shoot and root fresh weight, shoot and root dry weight, shoot and root dry matter ratio, root shoot dry matter ratio, shoot and root water content and seedling vigor index parameters were measured. Our results showed that increasing drought levels resulted in an overall significant reduction in germination and seedling growth parameters except shortened mean germination time (especially, 4% PEG6000 treatment) and increased shoot and root dry matter ratio at higher (especially, 8% PEG6000 treatment) drought levels. When important growth parameters such as length, fresh and dry weight, dry matter ratio and water content, which show the development of root and shoot organs, are evaluated together, it has been determined that the root is negatively affected by drought stress at a higher rate. Based on these data, it can be concluded that the L. corniculatus will suffer a high yield loss under the drought stress at the osmotic potential (-1.03 bar) created by 8% PEG6000 treatment.

Pengaruh Pemberian Berbagai Jenis Pupuk Kandang Terhadap Pertumbuhan Bibit Tanaman Kopi Robusta (Coffea canephora L) Pada Tanah Ultisol Di Polybag

This research aims to determine the effect of applying cow manure, goat manure and chicken manure on the seedlings growth of robusta coffee (Coffea cenophora L) in ultisol soil in polybags. This research was carried out since January to April 2023 at Pijoan Gardens, Campus II, Batanghari University and Laboratory of Batanghari University. The design used in this research was a completely randomized design (CRD) with one treatment factor, i.e. various types of manure which consist of 4 (four) treatment levels, namely: k0 : 3000 g of soil media without treatment (control), k1: 30 g cow manure + 3000 g ultisol soil, k2: 30 g goat manure + 3000 g ultisol soil, k3: 30 g chicken manure + 3000 g ultisol soil. Each treatment was repeated 3 (three) times. The parameters observed were soil water content, plant height, stem diameter, crown dry weight, root dry weight and root shoot ratio. The treatment of various types of manure had a significant effect on plant height, stem diameter, crown dry weight and root dry weight, but it had no significant effect on the root-shoot ratio of Robusta coffee seedlings. When this is compared with the control one, so the application of goat manure in treatment k2: 30 g of goat manure + 3000 g of ultisol soil gave the highest average results in several parameters such as plant height (79.00 cm) increasing 29.16%, stem diameter (8.40 mm) increased 38.84%, crown dry weight (24.84 g) increased 149.39% and root dry weight (11.09 g) increased 114.92%, and root shoot ratio (2.32) increased 20.83%, There were changes in the chemical characteristics of the soil, including the initial pH of 5.65 to 6.43-6.48 beside the highest soil water content was found in the k2 treatment at 11.99%.Key words: manure (cow, goat, chicken), growth, Liberica coffee, ultisol.

Adaptation of Two Tomato Varieties (Solanum lycopersicon L.) Under Salinity Stress

Abstract In order to study the adaptive behavior of two tomato varieties (Solanumlicopersicum L.) Safa and Assila subjected to salt stress with concentrations of (50, 100, 150 and 200 mM) in (NaCl+CaCl2) during the growth phase, a morphological (number of leaves, stem length, stomatal density, length of the main root axis) and physio-biochemical (relative water content, chlorophyll pigments content, soluble sugars content) evaluation was conducted. Our results confirm the sensitivity of both varieties to applied salt stress; this sensitivity was manifested by a statistically significant decrease in: number of leaves, length of the stem and the contents of chlorophyll a and total chlorophyll. While, the soluble sugars content at the leaf level increased associated with an increase stomatal density on both ventral and dorsal epiderms. On the other hand, the ratio of root dry weight and shoot dry weight (RDW/SDW) was decreased with an elongation of the main root according to the different doses of salts.

Bacterial strains effect on the nursery plants growth of ‘Granny Smith’ apple grafted on M-9, MM-106, and MM-111 rootstocks

Sapling treatment with plant growth promoting bacterial strains (PGPBs), is not spread on a wide scale for horticultural crops; basically, their application in fruit crops has not received much attention. For this reason, ‘Granny Smith’ apple was grafted on three clonal rootstocks using the chip budding method on 15 May 2013; at the end of the vegetative season, saplings with shoot lengths of 40 or less than 40 cm were selected as plant materials for the second year of research (2014) at the Abant Izzet Baysal University, Bolu, Türkiye to consider bacterial strains including Burkholderia gladia BA7, Bacillus subtilus OSU142 and Bacillus megatorium M3 in combination with different apple clonal rootstocks effectivity on the growth of saplings. Considering the results, the sapling weight at initially recorded between 8.6 and 36.0 g, the sapling weight at the end of the growing season 66.6–110.7 g, and the sapling weight increase rate between 181.7 and 789.1%. Root fresh and dry weight and root dry mater ratio obtained respectively 34.9–61.6 g, 15.3–34.1 g, and 44.8–57.8%. Sapling shoot length at the beginning was recorded between 15.1 and 35.6 cm, sapling shoot length at the end of the growing season ranged from 77.7 to 103.7 cm, sapling shoot length increase rate between 150.4 and 549.3%, and the number of lateral branches varied between 1.0 and 7.5 pcs. Briefly, bacterial strains application combined with the different apple rootstocks significantly affected all the evaluated characteristics of apple saplings. In light of the result findings, bacterial application in the nursery of apples as well as other fruit crops would be advised for better development and organically production of nursery plants.

PERTUMBUHAN TANAMAN KACANG TANAH YANG DIBERI BERBAGAI JENIS DAN TAKARAN PUPUK HIJAU PADA TANAH ULTISOL

This study aims to determine the effect of giving various types, doses of green manure and to determine the treatment that gives the best response on the growth of peanut plants on ultisol soils. This research was carried out at the Experimental Field Laboratory II and the Agrotechnology Laboratory of the UHO Faculty of Agriculture from April 2021 to February 2022. This study used a factorial randomized block design (RAK), namely the type of green manure (H) as the first factor consisting of 3 treatment: gamal leaves (H1), colopogonium (H2) and kirinyuh (H3) and the dose of green manure (T) as the second factor consisting of 4 levels of treatment: control (T0), 7.5 t ha-1 (T1), 15 t ha-1 (T2) and 22.5 t ha-1 (T3). The variables observed included stem diameter, number of leaves and nodules, leaf area, total leaf area, effective nodules, root dry weight and root loss ratio. The results showed that the application of various types and doses of green manure with kirinyuh (H3T3) was able to have a positive effect on increasing the growth of peanut plants grown on ultisol.

Short-Term Co-Application of Organic and Chemical Fertilizer Benefits Topsoil Properties and Maize Productivity in a Medium-Productivity Meadow-Cinnamon Soil

Co-application of organic-chemical fertilizer (CAOFCF) has attracted wide attention in China in recent years. However, its short-term effect on topsoil quality and maize yield in a medium-productivity meadow-cinnamon soil is not clear. In order to address this problem, a 3-year (2019–2021) field trial was established by arranging the following five treatments: (1) CF, applying chemical fertilizer alone; (2) OFCF1, 15% organic fertilizer + 85% chemical fertilizer; (3) OFCF2, 30% organic fertilizer + 70% chemical fertilizer; (4) OFCF3, 45% organic fertilizer + 55% chemical fertilizer; (5) OFCF4, 60% organic fertilizer + 40% chemical fertilizer. The results showed that short-term CAOFCF treatments were beneficial to the topsoil aggregate stability by increasing the percentage and mean weight diameter of macro-aggregate in topsoil. In addition, lower soil bulk density and higher soil organic carbon sequestration in topsoil were observed under the CAOFCF treatments. There was no difference in rhizosphere microbial diversity among all treatments. Compared to CF, OFCF1 and OFCF2 improved the activities of some key enzymes, including sucrase, urease, and acid phosphatase. Moreover, higher relative abundance of Actinobacteria and Chloroflexi were observed under the CAOFCF treatments. The root-shoot dry matter and maize grain yield were obviously higher in OFCF1 and OFCF2 than in CF; however, no significant difference was found in the OFCF3 and OFCF4 treatments compared to CF. The analysis of correlation suggested that there were no direct correlations between maize yield and various soil indexes measured. Nevertheless, root dry weight and root-shoot ratio were positively correlated with the activities of urease and sucrase. Meanwhile, the relationships between root dry weight, root-shoot ratio, shoot dry weight, and grain yield were all significant. In conclusion, short-term co-application of organic and chemical fertilizer (i.e., replacing 15–30% chemical fertilizer with organic fertilizer with an equal N rate) was beneficial to soil properties and maize grain yield in a medium-productivity meadow-cinnamon soil. The higher grain yield was associated with a strong maize root system, which was driven by the improved rhizosphere urease and sucrase activities.

THE EFFECT OF LOCAL MICROORGANISMS FROM COCONUT HUSK ON THE GROWTH OF OIL PALM (Elaeis guineensis Jacq.) IN THE MAIN NURSERY

THE EFFECT OF LOCAL MICROORGANISMS FROM COCONUT HUSK ON THE GROWTH OF OIL PALM (Elaeis guineensis Jacq.) IN THE MAIN NURSERY

Growth Performance of Bay (Laurus nobilis L.) Under Different Amount, Period of Watering and NPK

The aim of this work was to estimate the growth of Laurus nobilis seedlings under different levels, period of water and its interaction with NPK. Different amounts of water (150, 300 and 400) ml/polyethylene bag and irrigation intervals (two different scales are considered, once per week and once per two weeks) were used in addition to different amounts of NPK (zero (control), 500, 1000 ppm). Multi‐measurements and strategy was utilized for measuring stem length, stem diameter, root length, root diameter, moisture content, stem wet weight, stem dry weight, root wet weight, root dry weight and shoot root ratio. The results showed that bay seedlings had significantly affected by water amount (150ml) as well as water period (once per two weeks). Water deficit is therefore more commonly limiting seedlings growth than NPK through growing season. Therefore, sensitivity of bay seedlings to limitation water has indicated that decreasing in stem length, stem diameter, number of leaves, root diameter, moisture content, stem wet weight, stem dry weight, root wet weight, root dry weight and root shoot ratio (12.56cm, 3.35mm, 17, 3.66mm, 3.67%, 5.42g, 5.59g, 5.96g, 4.99g, 0.05). However, seedlings with three interaction (450ml, once/week and 1000ppm) had displayed significant differences through stem length, number of leaves, root diameter, moisture content, stem wet weight, stem dry weight, and root wet weight, root dry weight and root shoot ratio (28.16cm, 29, 6.57mm, 19.33%, 11.85g, 8.35g, 8.10g, 6.26g, 1.37 respectively). It is concluded that Laurus nobilis seedlings could not success in this area, especially under low water availability.
 

Oxygen consumption and transportation in rice roots are highly dependent on leaf area and root dry weight ratio

As rice is cultivated under diverse moisture conditions from paddy to field, the internal morphology of their roots may be diverse within species. This study aimed to investigate which traits affect the root oxygen consumption and transportation ability using rice varieties with different root anatomical traits. First, the CSR of seminal roots of six rice varieties was used to identify a variety with a low CSR. Results showed that the CSR in Sensho was the lowest in both aerated and stagnant solutions. Second, the shoot morphological traits, root anatomical traits, and root oxygen consumption and transportation of four rice varieties, including Sensho, were examined in preaerated and deoxygenated agar solutions. Results showed that deoxygenated conditions did not have any negative effects on the growth of the rice varieties. The root oxygen consumption rates were strongly positively correlated with the leaf area/root dry weight (LA/RDW, r = 0.90). The root oxygen transportation rates were also positively correlated with LA/RDW (r = 0.57). The percentage of root oxygen consumption compensated by oxygen transportation was highest in IR42, which had a low LA/RDW. Multiple regression using stomatal conductance, LA/RDW, and shoot dry weight as explanatory variables explained only 65.0% of oxygen transportation. We concluded that further studies on gas movements inside the shoots and roots are needed to clarify the mechanism that provides more sufficient oxygen to the roots.

Genome-Wide Association Mapping of Hulless Barely Phenotypes in Drought Environment.

Drought stress is one of the main factors restricting hulless barley (Hordeum vulgare L. var. nudum Hook. f.) yield. Genome-wide association study was performed using 269 lines of hulless barley to identify single-nucleotide polymorphism (SNP) markers associated with drought-resistance traits. The plants were cultured under either normal or drought conditions, and various quantitative traits including shoot fresh weight, shoot dry weight, root fresh weight, root dry weight, leaf fresh weight, leaf saturated fresh weight, leaf dry weight, ratio of root and shoot fresh weight, ratio of root and shoot dry weight, shoot water loss rate, root water loss rate, leaf water content and leaf relative water content, and field phenotypes including main spike length, grain number per plant, grain weight per plant, thousand grain weight (TGW), main spike number, plant height, and effective spike number of plants were collected. After genotyping the plants, a total of 8,936,130 highly consistent population SNP markers were obtained with integrity > 0.5 and minor allele frequency > 0.05. Eight candidate genes potentially contributed to the hulless barley drought resistance were obtained at loci near significant SNPs. For example, EMB506, DCR, and APD2 genes for effective spike number of plants, ABCG11 gene for main spike number (MEN), CLPR2 gene for main spike length, YIP4B gene for root and shoot dry weight (RSWD), and GLYK and BTS genes for TGW. The SNPs and candidate genes identified in this study will be useful in hulless barley breeding under drought resistance.

Growth and Yield of Patchouli (Pogostemon Cablin Benth) in Combination of Soil Améliorant and Fertilizer SP-36

Patchouli cultivation requires a fairly high nutrient intake and requires intensive cultivation actions. Land that is still widely available for cultivation of plantation crops is marginal land, so that in patchouli cultivation it is necessary to have input in improving soil fertility. The aim of the study was to determine the effect of soil enhancer, P fertilizer (SP-36) and the interaction between soil enhancer and P fertilizer (SP-36) on the growth and yield of patchouli. The study used a completely randomized block design with a factorial pattern with two factors. First treatment of soil améliorant (100% soil); 25% soil improvement materials and 75% soil; 50% soil améliorant and 50% soil). The second factor was SP-36 fertilizer (without SP-36 fertilizer; 1.8 g SP-36; 3.6 g SP-36, and 5.4 g SP-36 per plant). Each treatment combination was repeated three times. The variables observed were plant height, shoot dry weight, root dry weight, ratio of shoot and root dry weight, and patchouli yield. The results showed that the application of soil amendments at a dose of 25% and 50% in the planting medium gave better results on plant height, crown dry weight, and root dry weight, as well as the ratio of shoot and root dry weight. The application of SP-36 fertilizer and interactions at various doses did not have an effect on plant height, shoot dry weight, and root dry weight. The highest patchouli yield was found in the combination treatment of 25% soil améliorant and 5.4 g SP-36 on planting media with a yield of 4.2%.

Effects of Solar Radiation on Dry Matter Distribution and Root Morphology of High Yielding Maize Cultivars

The root system connects the plant with the soil, which is a key factor in determining the utilization of soil resources and plant growth potential. Solar radiation can change maize shoot and root growth and affect grain formation. In this study, the effects of different solar radiation conditions on root morphology of three maize cultivars XY335, ZD958 and DH618 and their quantitative relationships were studied by conducting shading experiments. This study was conducted in maize high yield region of Qitai and Yinchuan, China, in 2018 and 2019. The planting densities were 7.5 × 104 (D1) and 12 × 104 (D2) plants ha−1. The shading levels were natural light (CK), shading 15% (S1), 30% (S2) and 50% (S3). The results showed that maize responded to the decreased solar radiation through the increase in ratio of shoot dry weight (SWR) to whole plant dry weight and the decrease in ratio of root dry weight (RWR) to whole plant dry weight. As the solar radiation decreased, the root length density (RLD), root surface area (RSA), average root diameter (ARD) and root length ratio (RLR) decreased, while the specific root length (SRL) increased. With 100 MJ m−2 decrease in solar radiation, the RWR, RLD, RSA and RLR each decreased by 1.47%, 0.5 mm cm−3,0.4 m m−2 and 0. 19 m g−1, respectively. Among the cultivars, the changes of DH618 were the fastest followed by XY335 and ZD958 but DH618 maintained the largest root system under any solar radiation condition. After the decrease of solar radiation, RWR, RLD and RLR were significantly positively correlated with the yield. This indicated that large root systems were conducive to the rapid response to decreased solar radiation and important for achieving stable and high yield. Maize cultivars with these type of root systems should be recommended to better adapt low solar radiation induced by regional variation or climate change.

Variation of Morphological Traits and Quality Indices of Micropropagated Melia volkensii Gürke Clones before Field Planting

The quality of acclimatized in vitro cultivated plants is essential to ensure good survival and growth after planting in field conditions. After two months of acclimatization, this study revealed a significant variation in survival rate, shoot characteristics, root traits, and biomass features between 13 clones of Melia volkensii Gürke. A number of quality indices such as the Dickson Quality Index (DQI), shoot dry weight: root dry weight ratio (S:R), and sturdiness quotient (SQ) also showed a large variation. The survival rate was genotype-dependent, with an average of 85%. Extreme genotypes were tall, had long internodes, a lot of leaves, and a large leaf area. At the other side of the spectrum, there were small clones with short internodes and a reduced number of leaves and leaf areas. The high S:R values (>2) of the evaluated clones indicate an imbalance between the shoot and root system, negatively influencing the quality of the in vitro produced M. volkensii plants. The SQ for all clones was below the threshold value of 6, implying a good and expected survival rate. This study illustrates that some clones might systematically score better for SQ, S:R, plant volume, and DQI after acclimatization and that these factors could form the basis for selection.

PERTUMBUHAN BIBIT KOPI ARABIKA (Coffea arabica L.) PADA BERBAGAI PEMUPUKAN DAN URINE SAPI

Seedling on Arabica coffee plants (Coffea Arabica L.) is a stage that will determine plant productivity in the field, therefore it needs to be supported by quality seeds (superior seeds), resistant to pests and diseases and response to fertilization. So it is necessary to do research on the growth of coffee seedlings on various fertilizers and cow urine. This study aims to determine the number of fertilizers (SP-36, KCl, cow manure) and cow urine on the best growth of coffee seedlings in nurseries. The research was conducted at Sempaja Village, North Samarinda District and at the Agronomy Laboratory of Faperta Unmul Samarinda in 2017. This study consisted of 4 experiments where each experiments were arranged in a Completely Randomized Design (CRD) with 4x4 factorial experiments with two replications. The first experiment was the dose of SP-36 ) fertilizer (P) consisted of four levels, namely, 0 g polybag-1 , 5 g polybag-1 , 7 g polybag-1 , 9 g polybag-1 and cow urine concentration (S) consisted of four levels, namely, 0 mL L-1 , 250 mL L-1 , 300 mL L-1 , 350 mL L-1. The second experiment was the dose of KCl fertilizer (K) consisted of four levels, namely, 0 g polybag-1 , 4 g polybag-1 , 5 g polybag-1 , 6 g polybag-1 and cow urine concentration (S) consisted of four levels, namely, 0 mL L-1 , 150 mL L-1 , 200 mL L-1 , 250 mL L-1. The third experiment was the dose of cow manure (A) consisted of four levels, namely, 0 g polybag-1 , 250 g polybag-1 , 500 g polybag-1 , 750 g polybag-1 and cow urine concentration (S) consisted of four levels, namely, 0 mL L-1 , 75 mL L-1 , 150 mL L-1 , 225 mL L-1. Parameters observed in each study at four months after treatment included: increase in plant height, number of leaves and stem diameter, dry weight of plants, shoot dry weight, root dry weight and root crown ratio. Data were analyzed using variance and continued with the least significant difference test at 5% level. The results of the study on the application of various fertilizers (SP-36, KCl and cow manure) showed a very significantly difference to the increase in seedling height, number of leaves and stem diameter but not significantly different to plant dry weight, shoot dry weight, root weight and ratio root crown at three months after treatment. The application of cow manure can increase the yield of plant dry weight, shoot dry weight, root dry weight and root crown ratio. Meanwhile, the concentration of cow urine and the interaction between each fertilizer ( SP-36, KCl and cow manure) and the concentration of cow urine were not significantly different for all parameters. Giving cow urine can increase the yield of plant dry weight, shoot dry weight, root dry weight and root crown ratio.

PERTUMBUHAN TANAMAN SERAIWANGI (Cymbopogon nardus L) PADA BEBERAPA DOSIS KOMPOS KULIT KOPI

The purpose of this study was to determine the effect of giving coffee husk compost on the growth of citronella (Cymbopogon nardus L.) plants. This research was conducted in Kuala Tungkal, Tungkal Ilir District, West Tanjung Jabung Regency, Jambi Province, from December 2020 to March 2021. Analysis of compost nutrients was carried out at the Laboratory of the Jambi Agricultural Technology Research Center and measurements of root wet weight, shoot dry weight and root dry weight were carried out at the Basic Laboratory of Batanghari University Jambi. This research was conducted using a randomized environmental design (CRD) and treatment design for coffee husk compost which consisted of 4 levels of treatment, namely k0 : 3 kg of soil media without treatment (control), k1 : 15 g of coffee husk compost + 2,985 g of soil media, k2 : 22.5 g coffee husk compost + 2.977.5 g soil media, and k3 : 30 g coffee husk compost + 2.970 g soil media. The results of the analysis showed that the application of coffee husk compost had a significant effect on the parameters of root wet weight, shoot dry weight and pH of the growing media but had no significant effect on the parameters of the number of tillers, number of leaves, root dry weight and root crown ratio

The Effect of Different Growing Environments on Seedling Development in Transplanting Paddy Production

In the world, the seedling planting method comes into prominence to save on irrigation water due to climatic changes, to increase the yield per unit area with lengthy vegetation varieties, and to reduce chemical input in pest and disease control. The basic element of being successful in transplanting paddy production is to grow healthy and quality seedlings. For machine transplanting, it is necessary to grow in a special viol environment. For paddy seedlings in trays, it is required to prepare special mortars rich in plant nutrients and economical. In this research, four replications were carried out in an unheated polyethylene greenhouse of Ondokuz Mayıs University Agricultural Research and Application Center in 2020 with 20 different mortar media and three paddy varieties (Baldo, Vasco and Tosya Güneşi). To determine the seedling quality, seedling length, seedling stem diameter, leaf number, root length, root number, above ground and root wet weight, above ground, and root dry matter ratio values were examined 21 days after planting. According to the research results, the effect of different medium crosses, cultivars, and environment x cultivar combinations used on the seedling quality characteristics was statistically significant. The results showed that seedling length was 68.39-218.19 mm, seedling stem diameter was 0.97-2.64 mm, number of leaves was 2.0-4.0, root length was 16.95 - 98.35, number of roots was 4.25-10.75, shoot wet weight 5.40-131.55 mg, root wet weight 3.03-104.28, shoot dry weight ratio was 5.95-27.42%, and root dry weight ratio was 1.37-15.13%. The biplot analysis results showed that the Vasco variety had the best quality of seedlings in growth media numbers 13 and 18. The evaluation of growth media's quality, economically and ecologically, showed that growth media number 13 was the best media, and media numbers 18 and 19 could be used as alternatives.

干旱对不同品种小麦幼苗的生理生化胁迫以及外源5-氨基乙酰丙酸的缓解作用

<p id="C3">Drought stress happens frequently in Huang-Huai winter wheat planted area, causing severe injury on photosynthetic apparatus of wheat seedlings. To characterize the traits of photosynthetic physiology in different wheat cultivars in response to water deficit, the newly in-lab cultivated Zhengmai 1860, as well as Bainong 207 and Zhoumai 18 were used as materials in this study. We explored the effects of water deficit on photosynthetic traits, antioxidant enzyme activities, and related gene transcription of seedlings in different cultivars, as well as the drought alleviation effect of exogenous application of 5-aminolevulinic acid (ALA). The results were as follows: Zhengmai 1860 had comparatively higher root dry weight and root shoot ratio than the other two cultivars under drought stress. Compared to Zhoumai 18, the drought resistant cultivars (Zhengmai 1860 and Bainong 207) had lower reduction in chlorophyll content and increased MDA content, enhanced the activities of SOD and CAT, and lowered reductions in chlorophyll fluorescence parameters and the photosynthetic parameters. Meanwhile, water deficit obviously improved the transcriptions of antioxidant enzyme-encoded genes <italic>CAT</italic>, <italic>SOD-Cu/Zn</italic>, <italic>MnSO</italic>, and<italic> FeSOD</italic>, which showed a correlation between the increasing level with the drought resistant ability. The exogenous pretreatment of ALA further enhanced the activities of SOD and CAT to lower the damage to membrane lipid peroxidation by inducing the transcriptions of <italic>CAT</italic>, <italic>SOD-Cu/Zn</italic>, and <italic>MnSOD</italic>. ATPase activity was also increased to alleviate water deficit on the damage to photosynthetic physiology. Moreover, we found for the first time that the transcriptional maintenance of chloroplast photosynthetic apparatus related <italic>psb28</italic> gene had a correlation with the drought resistance between different wheat cultivars, which was also significantly induced by the exogenously pretreated ALA. These results in this study proposed that the transcriptions of antioxidant enzymes and chloroplast photosynthesis related genes had a close relationship with the drought resistant ability of wheat and the alleviation effect of exogenous ALA in wheat.

Effect of exopolysaccharide-producing Azotobacter and cow manure on nutrient uptake and root-to-shoot ratio of sorghum

Nitrogen-fixing Azotobacter synthesizes exopolysaccharide, which is important among other to improve aggregate stability and hence nutrients uptake. A pot experiment has been conducted to determine the effect of exopolysaccharide-producing Azotobacter and organic matter on nitrogen, phosphor, and potassium uptake by the shoot of sorghum (Sorghum bicolor (L.) Moench), and plant growth. The pot experiment was setup in randomized block design which test eight combination treatments of Azotobacter isolates (AS5, AS6, and AS5 + AS6) and organic matter application (with and without 20 t ha-1 of cow manure). The result showed dual inoculation of Azotobacter AS5 and AS6 inoculation combined with cow manure application increased N and P uptake. The dual inoculation treatment did not affect root length; but increased the shoot height and dry weight when accompanied by the application of cow manure. The ratio of root and shoot dry weight was not influenced by single or dual Azotobacter inoculation with or without organic matter.

Genome‐wide association study of soybean (Glycine Max) phosphorus deficiency tolerance during the seedling stage

AbstractPhosphorus (P) is essential for plant growth, especially for soybean. P deficiency results in a severe decline of soybean productivity worldwide. Biomass is an important index to measure the tolerance of plants to low P. In this study, SNPs significantly associated with four P deficiency tolerance‐related traits were identified by genome‐wide association study (GWAS) using a natural population comprised of 272 soybean accessions from a wide geographic range and a high‐density NJAU 355K SoySNP array. As a result, four SNPs associated with RPDW (ratio of root dry weight under normal P condition and low P condition) with similar positions on chromosome 18 were identified and explained 24.71% to 30.89% of the phenotypic variation. One of these SNPs was identified in two environments and with two traits. Two genes were chosen as candidate genes responding to low P stress, one of which was annotated as a copper transporter and the other was annotated as a lipid transfer protein. In brief, these findings will be helpful for improving P efficiency and the marker‐assisted selection breeding in soybean.