Root Dry Matter Yield Research Articles

Evaluation and selection of cassava clones and exploitation of genetic covariance across multiple environments

AbstractClonal evaluation trials of cassava (Manihot esculenta Crantz), where the main selection of this crop takes place, are usually carried out in multiple environments. This study investigated the influence of genotype–environment (GE) interaction on selection and how to explore genetic information across environments in a mixed model approach by modeling different genetic covariance structures. Approximately 240 cassava clones were assessed in an augmented block design during the 2020/2021 growing season in Brazil. The unstructured model was the best suited and used to investigate several strategies of selection. The predicted genetic gains based on individual analyses varied greatly among environments (5.52%–12.62% for root yield; 1.00%–6.09% for dry matter content; and 4.01%–9.42% for dry matter yield), although the clones mean was similar. Moreover, most of the selected clones in each environment outperformed the best check (>80%), except for root yield and dry matter yield in one environment. By multi‐environment analysis, greater local gains were detected in each environment (means of 16.87% for root yield, 5.56% for dry matter content, and 17.27% for dry matter yield) and for mean heritability (0.52 for root yield, 0.76 for dry matter content, and 0.55 for dry matter yield). The coincidence of clones selected by individual and multi‐environment analyses was 64% for root yield, 73% for dry matter content, and 66% for dry matter yield. The best scenario for selection is when all environments are considered simultaneously, for which regional genetic gains of 16.71% were predicted for root yield, 5.40% for dry matter content, and 17.06% for dry matter yield.

Effect of Zn Applied with or Without Palm Stearin Coated Urea on The Growth and Mineral Element Concentration of Maize (Zea mays L.)

Inhibition of ammonia (NH3) volatilization by deaccelerating urea hydrolysis rate in Central Anatolian lands is the indispensable approach for eco-friendly fertilization and nitrogen use efficiency (NUE). Nitrogen (N) and zinc (Zn) are critically limited here in alkaline soils. An experiment was conducted under controlled conditions to determine the availability of Zn applied as a solution and bound with polymer palm stearin (PS) coating material as a urease inhibitor. The treatments consisted of urea as a commercial commodity, urea with PS only, urea impregnated with PS and Zn, Zn-coated urea, and Zn in solution (SOL) form. During winter, 2019-20, the experiment was conducted in the glasshouse of the department of Soil Science and Plant Nutrition at Ankara University, Türkiye. Data indicated that Zn with PS and in SOL form produced more growth traits i.e., plant height (130 cm), stem girth (13.2 mm), shoot dry matter (4.63 g plant-1), root dry matter yield (0.61 g plant-1), and chlorophyll (42.16 mg g-1) content (p<0.01). Similarly, we had higher concentration of N (3.19%) and Zn (50.46 mg kg-1) content in maize plants (p<0.01) as compared to control. In conclusion, Zn at the rate of 10 mg kg-1 either in solution or coated with urea seems highly effective to sustain better crop productivity and NUE. While concerning N and Zn content, coated urea with Zn markedly responded as compared to Zn in SOL. Synergism between N and Zn can lead to better fertilizer management

Cultivation of Cassava (Manihot Esculentus C.) With Selected Legumes for Growth, Yield and Economic Advantages as Climate Change Mitigations

Cassava (Manihot esculentus Crantz.) is a monoecious perennial shrub that is extensively cultivated as an annual crop in tropical and subtr++=opical regions for its edible, starchy, tuberous roots. It is ideal for intercropping with short-duration crops, which are often harvested before the cassava canopy closes. Thus, intercropping cassava, especially with legumes, is an important way for poor farmers to provide additional crop yield during the early growth stage. Moreover, the incorporation of legumes into cassava-based cropping systems may offer one of the most feasible ways of enhancing protein intake and nutritional security of farming households. Accordingly, a 1-year field study on cassava intercropped with three legumes (haricot bean, mung bean, and soybean) in southern Ethiopia was conducted to determine the effect of intercropping on the growth, yield, and economic advantage of the cassava. The experiment was laid out in a randomized complete block design (RCBD) with three replications. The results revealed that there were significant (P<0.05) differences for cassava plant height, leaf number, stem width, number of storage roots per plant, storage root weight, dry matter, and root yield due to cassava legume intercropping. Cassava- haricot bean intercropping increased root yield by 28% as compared to cassava-mung bean (21%), and cassava-soybean (18 %), respectively. And it can improve land-use efficiency by 31% as compared to cassava-soybean and cassava-mung bean intercropping. The partial budget analysis also revealed that cassava planted with haricot bean gave the highest economic benefit of 199,250 Birr ha-1. Further researches on relative planting time of legumes with cassava and soil fertility variation under sole cassava and intercropping systems are important for improving productivity of growers under the study area.

Mung Bean Nutrient Uptake and Root Response to Phosphorus and Potassium Placement Strategies

ABSTRACT A pot experiment was conducted to examine the effect of co-application of phosphorus (P) and/or potassium (K) fertilizer to a soil layer on Mung bean (Vigna radiata R. Wilczek) grown in a Yellow Chromosol soil. We hypothesized that adding K to a P- enriched soil layer would increase recovery of K due to increased root proliferation. Layers enriched with P, K or a combination of P and K were placed at either 5 or 20 cm depth in 50 cm deep pots, and a uniform PK application treatment included for comparison. Mung bean was grown for 45 days and key growth and nutrient uptake attributes were assessed. Phosphorus application increased shoot and root dry matter yield and shoot yield was 40% higher in the shallow P treatment and 77% higher in the shallow PK than in the uniform PK treatment. Shallow co-application of P and K increased shoot P and K content compared with shallow P alone. Apparent P fertilizer recovery (%PAFR) followed the same pattern, and there was an 8 to 12-fold increase in %KAFR. There was no evidence of an increase in either the proportion or mass density of roots in the enriched soil layers in any treatment. P and K fertilizer use efficiency was maximized by co-application in an enriched soil layer. When multiple nutrient deficiencies occur co-application of nutrients in a soil layer accessible to roots maximizes fertilizer use efficiency.

English

Immobilization is an efficient method in the remediation of heavy metal-polluted soils. A greenhouse experiment was conducted to investigate the influence of fish scale powder, chitin, and chitosan on the growth and chemical composition of rice grown on a soil contaminated with Zn, Pb, Cd, and Ni. Results showed that the application of fish scale powder, chitin, and chitosan significantly increased root and shoot dry matter yield of rice, but decreased Pb phytoextraction efficiency. Further, the translocation factor of Ni decreased following the application of fish scale powder and chitosan. Application of fish scale powder decreased Ni, Cd, Zn, and Pb bioavailability in soil. The addition of chitosan caused 56% decrease in shoots Ni concentration as compared to control. Among different amendments, only the application of chitosan had a significant effect on the reduction of Zn content in rice root by 70% as compared to control. Considering that the translocation factors were less than one in all treatments, it can be concluded that biostabilization of the studied metals has occurred. Based on the obtained results, fish scale derivatives including fish scale powder and chitosan play an important role in the removal of heavy metals due to having suitable functional groups. Therefore, it can be deduced that due to the economic feasibility, environmentally friendly, and high metal removal capability of chitosan and fish scale powder, these two amendments are highly recommendable to be applied in multi-metal polluted soils for increasing metals removal and hence decreasing their phytotoxicity.

Lasting effect of Urochloa brizantha on a common bean-wheat-maize rotation in a medium-term no-till system

Grass intercropping under no-till is an option to increase crop residues on the soil surface and crop diversity. Urochloa spp. is frequently selected for intercropping to improve land use and agricultural production because of its high residue production, slow residue decomposition, as well as its vigorous, abundant, and deep root system. However, the effects of intercropping Urochloa and maize, especially the effects of Urochloa residues, on subsequent crops in rotation have not been established. To address this knowledge gap, a field experiment was carried out over 5 years (from 2014 to 2018) comprising 2 years of maize monocropping or intercropping and 3 years of crop rotation (common bean-wheat-common bean-wheat-maize). We evaluated the medium-term effects of monocropped maize or maize intercropped with Urochloa brizantha on soil fertility and the development, yields, and grain nutrient accumulation of subsequent common bean, wheat, and maize crops. The cultivation of U. brizantha in the intercropping system improved soil fertility over at least 4 years, with increases in soil pH; soil organic matter (SOM); phosphorus (P); exchangeable potassium (K), calcium (Ca), and magnesium (Mg); sulfur (S–SO42−); cation exchange capacity (CEC); and base saturation (BS) at all soil depths. The benefits of U. brizantha extended to root dry matter and distribution; 70–77% of the total roots were concentrated within a soil depth of 0.0–0.2 m. The intercropping system improved the root dry matter mass, yield components, and grain yields of subsequent common bean, wheat, and maize crops in all cultivation years. These findings indicate that intercropping maize and U. brizantha provides medium-term benefits for subsequent common bean, wheat, and maize crops, and improves nutrient cycling to increase soil P; exchangeable K, Ca, and Mg; S–SO42−; and organic matter content.

Cloning, subcellular localization and expression of phosphate transporter gene HvPT6 of hulless barley.

Deficiency of phosphate (Pi) is one of the main growth-limiting factors for crops. Generally, phosphate transporters play a key role in the uptake of P in the crops. However, current knowledge regarding the molecular mechanism underlying Pi transport is still limited. In this study, a phosphate transporter (PT) gene, designated HvPT6, was isolated from a cDNA library constructed from hulless barley "Kunlun 14." The promoter of HvPT6 showed a large number of elements related to plant hormones. The expression pattern also indicated that HvPT6 was highly induced by low phosphorus, drought, abscisic acid, methyl jasmonate and gibberellin. Phylogenetic tree analysis revealed that HvPT6 belongs to the same subfamily of the major facilitator superfamily as OsPT6 from Oryza sativa. Subcellular localization of HvPT6:GFP using transient expression of Agrobacterium tumefaciens showed the green fluorescent protein signal in the membrane and nucleus of the Nicotiana benthamiana leaves. Overexpressing HvPT6 led to a longer and higher lateral root length and dry matter yield in the transgenic Arabidopsis lines under low Pi conditions, indicating that HvPT6 improves plant tolerance under Pi-deficient conditions. This study will lay a molecular basis for phosphate absorption mechanism in barley and breeding barley with high-efficient phosphate uptake.

Soybean extracts can improve plant development

Microbial biodiversity of an environment can contribute to plant growth and increase crop yield. Plant extracts from soybean (Glycine max (L.) Merrill) were investigated on soybean plants grown after inoculation with these extracts. Soil samples were collected from two important Brazilian soybean-growing regions to produce the extracts used in the experiments. The extracts were produced with material collected from aboveground biomass and rhizosphere of soybean plants cultivated in a controlled greenhouse (phase 1). The extracts produced in phase 1 were applied in a sequential experiment (phase 2). Phase 2 was conducted to examine the plant microbiome after the microbial alteration process in the greenhouse through seed inoculation with the extracts produced previously. Samples of aboveground biomass were collected to determine root dry matter and crop yield. Bacterial 16S rRNA sequences were processed to determine the final microbial content of soybean. The inoculated treatments had lower species diversity; however, the phyla Firmicutes and Bacteroidetes were more abundant in the treatments than in the non-inoculated treatment. The soybean plant stem in the inoculated treatment also had a positive response to enrichment of the bacterial classes Betaproteobacteria, Bacilli and Flavobacteria. Inoculation affected the microbial composition of soybean plants. The alteration of microbiome changes revealed differences for crop yield between the inoculated and non-inoculated treatments, with up to 93.5 % higher crop yields per plant according to the extract applied.

Rice demands higher nitrogen fertilizer during grain filling stage under elevated atmospheric CO2 condition

An experiment was conducted in open top chamber (OTC) to determine the response of rice to elevated carbon dioxide (eCO2) under varying time of nitrogen (N) application. Rice was grown in OTC with 500 ppm CO2 (eCO2), 450 ppm CO2 (intermediate CO2, iCO2), ambient CO2 (aCO2) and open field (OF, 380 ppm CO2). The timings of N application were N1 = 1/3rd N at early tillering (ET) + 1/3rd at active tillering (AT) + 1/3rd before panicle initiation (PI) stage, N2 = 1/3rd N at ET + 1/3rd before PI + 1/3rd at booting stage (BS), and N3 = 1/3rd N at ET + 1/3rd before PI + 1/3rd at flowering stage (FS). The results revealed that photosynthesis (Pn), shoot and root dry matter (SDM and RDM) production, yield and yield components were favored at eCO2 when N application scheduled from ET to FS of rice. Interestingly, the N application up to FS of rice showed significant improved grain fertility and reduced sterility under rising CO2. However, rice plant accumulated and translocated more nutrients from shoot to grain under elevated CO2 (eCO2) condition. Moreover, higher grain amylose and lower protein was obvious at eCO2. Collectively, rice yield increased by 18 to 20 % under eCO2 with the application of N at FS of rice. These results indicate that to maximize rice yield under eCO2, it is crucial to supply N at FS of rice in order to increase grain fertility and reduce spikelet sterility

Effects of K Fertilizer and Different Soil Content on Chickpea(Cicer Arietinum L.) Yield and Membrane Permeability under Dry Conditions

This study was conducted as a pot experiment potassium fertilizer different doses effects were investigated plant growth and membrane permeability on chickpea plants in dry conditions in Gaziantep province. The experiment was designed as a randomized block design with 3 replications. The 18 pots were composed of two different textures as 1:1 torf+soil and only soil in the experiment. Three different doses potassium fertilizer (Control: 0ppm K, 100ppm K, 200ppm K) were given with seed sowing. Chickpea plant was harvested at the end of 8 weeks and results were evaluated. Plant dry matter yield was found between 19.60g/pot and 52.25g/pot. As applied potassium fertilizer dose has decreased plant root and leaf dry matter yield has also decreased when potassium doses increased these values have increased. Torf+soil mixture texture has supported plant growth. The effect of potassium fertilizer on plant growth and membrane permeability was found statistically significant (p

Determination of The Resistance of Grapevine Rootstocks to Cadmium (Cd) Toxicity

In this study, response of 12 grapevine rootstock genotypes to cadmium (Cd) toxicity were investigated. The Cd application to the soil was made at the beginning of the experiment at 4 different doses. Shoot, leaf and root dry matter yields, leaf Cd, N, P and Zn contents were determined to assess genotype tolerance of Cd toxicity. Present findings revealed that based on shoot, leaf and root dry weights, leaf Cd, N, P and Zn contents, there were Cd-sensitive and resistant genotypes among the present ones. At the greatest Cd dose (Cd20), the greatest Cd contents (µg plant-1) were observed in 8B (6.13), 420A (5.35) and 1103P (4.69) rootstocks and the lowest Cd contents were observed in 99R (1.27) and SO4 (1.58) rootstocks. Among the grapevine rootstocks, SO4 with quite lower leaf Cd accumulation than the other genotypes and increasing shoot and leaf dry weights and leaf N, P and Zn content was identified as resistant against toxic Cd conditions. On the other hand, 8B, 420A, 1103P, 5BB, Harmony genotypes with decreasing shoot, leaf and root dry weights under Cd toxicity conditions, higher leaf Cd accumulations and significantly decreasing leaf N, P and Zn contents were considered as sensitive to Cd toxicity.

Contribution of the carbonized rice husk added to the substrate in the production of vegetable seedlings

The carbonized rice husk (CRH) is an agro-industrial residue with great potential for use in mixtures with other substrates for the production of vegetable seedlings. Thus, the purpose of this study was to evaluate the effect of the addition of CRH to the commercial substrate for the production of greenhouse seedlings. The evaluated vegetables were lettuce, broccoli and mustard, cultivated in polystyrene foam (Styrofoam®) trays. Five treatments were evaluated: 100% of the commercial substrate (CS); 25% of CRH + 75% of CS; 50% of CRH + 50% of CS; 75% CRH + 25% CS; and 100% CRH, in a completely randomized design with twelve replicates. The substrates were evaluated for their physical and chemical characteristics. The morphometric evaluations were: number of leaves per plant, plant height, shoot fresh matter yield, root length, and shoot and root dry matter yield. The data were submitted to regression analysis, and the homogeneity of the variance between the experiments was confirmed by the Cochran test. With the addition of CRH to the substrate, there was an increase in total porosity and P content and a reduction in density, water holding capacity, cation exchange capacity, electrical conductivity, and N, K, S, Ca and Mg contents. The carbonized rice husk added to the commercial substrate is a viable alternative for the production of lettuce, broccoli and mustard seedlings. The quality of the vegetable seedlings was higher when there was a 25% CRH + 75% CS mixture.

Understanding changes in cassava root dry matter yield by different planting dates, crop ages at harvest, fertilizer application and varieties

Cassava is a perennial crop that can adapt to periods of drought at different times in a growing season, which permits scheduling planting and harvest to develop production systems supplying roots continuously. However, farmers plant and harvest cassava at the onset of rains which creates glut and results in unattractive root prices. Thus, farmers need to understand how cassava varieties respond to different planting dates and crop ages at harvest to be able to use opportunities in income generation that may arise from flexible planting and harvest dates resulting from price and dry matter (DM) variabilities. Thus, this study was conducted to identify the best time to plant and harvest cassava for different varieties (TME419 and TMS581) and to determine the effect of fertilizer on root DM yields in three locations (Idi-Ose, Moniya and Ido) in Nigeria, over two years. The overall objective was to provide information to guide farmers on how to schedule planting and harvesting in Nigeria. The trials were conducted using a factorial split-split plot design. Effects of early, mid and late planting dates combined with harvest at 9, 11 and 13 months after planting (MAP) were tested. Fertilizer treatments included a control (F0) and applications of 75 kg N ha−1, 20 kg P ha−1 combined with 90 (F1), 135 (F2) and 180 (F3) kg K ha−1. A root DM yield increase of 44.8% was observed when crop age increased from 9 to 11 MAP, and an increase of 13.1% when crop age increased from 11 to 13 MAP, indicating that delaying harvests does increase root DM yield across all planting dates. In contrast, root DM yield differences between planting dates were marginal, an increase of 8.1% was observed from early to mid-planting date and of 9.5% from early to late planting dates. Fertilizer treatments significantly interacted with location and the largest responses were observed at Ido. Fertilizer increased cassava root DM yields when compared with control at Ido by 15.38%, 23.1% and 16.7% in F1, F2 and F3, respectively. Responses were inconsistent at Moniya and Idi-Ose. With information on the effect of crop age and fertilizer, farmers could benefit from targeting seasons with shortage of cassava roots and high cassava prices, which would benefit processing industries securing year-round root supply.

Water–phosphorus coupling enhances fine root turnover and dry matter yield of alfalfa under drip irrigation

AbstractAlfalfa (Medicago sativa L.)is an important forage with high quality and fine root turnover rate (FRTR). Soil phosphorus (P) availability greatly influences dry matter yield (DMY) and persistence of alfalfa. However, the effects of water (Wa)–P coupling under drip irrigation conditions on alfalfa FRTR and DMY have been rarely studied. Therefore, a 2‐yr field experiment was established with three randomized complete blocks in Xinjiang, China, evaluating three irrigation amounts (5,250, 6,000, and 6,750 m3 ha−1, referred to as W1, W2, and W3, respectively) and four P application rates (0, 50, 100, and 150 kg ha−1, referred to as P0, P1, P2, and P3, respectively) in 2017 and 2018. The Wa–P interaction had a significant effect on alfalfa DMY (P < .05), and DMY reached the maximum at W2P2 treatment. Fine root biomass (FRB) presented a bimodal pattern over time (on 21 June and 20 August) and mainly existed in the soil layers 20‒40 cm underground. All root variables including FRB were positively correlated with alfalfa DMY. Comprehensive analysis showed that W2P2 was the optimal treatment of the 12 treatments. Therefore, the irrigation amount of 6,000 m3 ha−1 and P application rate of 100 kg ha−1 seems beneficial to achieve the relatively rational FRTR and the greater DMY of alfalfa.

Evaluation of the Sulphur-Supplying Ability of Soils to Support Plant Growth and Assessment of Relative Crop Response to Sulphur Application through Neubauer Technique

Sulphur plays a vital role in the nutrition of oilseeds and pulses. Along with nitrogen and phosphorus, it plays an important role in the formation of proteins and is involved in the metabolic and enzymatic processes of all living cells. Several biological techniques have been studied in order to assess sulphur deficiency or sufficiency in different groups of sulphur fertilizer for achieving the optimum yield of crops of which Neubauer technique is generally considered as one such tool that can be used for piloting the sulphur supplying capacity of the soils to supplement its requirement for the establishment of the plant. Surface (0-15 cm) soil samples from typical rice and pulse growing fields spread over the dominant soil groups of West Bengal which belong under 16 identified soil series were collected for this study. In order to assess sulphur availability in soils Neubauer technique was employed. Under sulphur treatment, the lowest dry matter yield and uptake by shoot was recorded in Bankul soil. Among the soils, the lowest root dry matter yield at control treatment was recorded in patapahari soil and the highest was in Hijalgara soil. A similar trend was also observed in case of S uptake by the shoot. While highest dry matter yield and maximum sulphur uptake by shoot was registered in Sukhnibasa and kusmi soil respectively. Likewise for N, P and K elements, the Neubauer technique may be used as one of the biological techniques for evaluating S response to crops as well as S supplying capacity of the soil to support plant growth.

Soil compaction and cover with black oat on soybean grain yield in lowland under no-tillage system

ABSTRACT: Brazil is the largest exporter and second largest producer of soybean grains. Most of this production is from plants grown under no-tillage system (NT). This research evaluated the effect of soil compaction, and different amounts of black oat residues on the soil surface on soybean growth and grain yield in lowland under NT. The experiment was conducted in a completely randomized design with seven treatments and four replications, in the 2016/2017 and 2017/2018 crop seasons. The treatments consisted of: 1) winter fallow without soil compaction (WF); 2) winter fallow with soil compaction (WF-C); 3) black oats and complete removal of surface residues, with soil compaction (0R-C); 4) black oats and removal half of surface residues, with soil compaction (0.5R-C); 5) black oats without surface residue removal, with soil compaction (1R-C); 6) black oats without surface residue removal, plus the residues from treatment 3, with soil compaction (2R-C); 7) black oats without surface residue removal, without soil compaction (1R). When the soybean plants were at the phenological stage R2, they were evaluated nodule, root and shoot dry matter, nitrogen contents, plant height, and grain yield. The soil physical properties were evaluated in the 0.0-0.05, 0.10-0.15 and 0.20-0.25 m layers. The soybean aerial dry matter is > 38% in non-compacted soil in year with soil water excess, regardless of the amount of surface oat straw. In year with small water deficit, soil with more surface oat straw produced > 5% shoot dry matter and > 4% of soybean grain, regardless of compaction. The plant growth and grain yield soybean in lowland varied according to the water conditions, and were affected by soil compaction and amounts of black oats residues on soil surface.

Fodder Beet (Beta Vulgaris Var Crassa) Yield and Quality Attributrs As Affected By Nitrogen Fertilization and Foliar Boron Application

A field experiment was conducted during two seasons 2018/2019 and 2019/2020 at Homs Agriculture Research Center, General Commission for Scientific Agriculture Researches (GCSAR), Syria, to study the effect of nitrogen fertilization rates and foliar application of boron on root yield and quality and dry matter yield of fodder beet. Results showed that the effect of nitrogen fertilization was significant (p≤0.001) for all studied traits except brix%. The effects were significant positive on root, shoot and biological yields, sucrose percentage, root, shoot and total dry matter yields. On the other hand the effect of boron spraying was presented for each season separately, because the differences of boron treatments were significant for all parameters except brix% at each season, and HI at the two seasons, while the differences of years were significant for all parameters except for HI. the highest yield and yield components were achieved by adding 300 kg N/ha with the addition of boron under Homs governorate conditions.

Evaluation of the Effects of Organic and Mineral Fertilizers with Mycorrhiza on the Dry Matter Yield and Nutrient Uptake of Theobroma Cacao in Ibadan, Nigeria

A greenhouse trial was conducted at Cocoa Research Institute of Nigeria, Ibadan, to evaluate the effects of organic and mineral fertilizers with and without Mycorrhiza on the dry matter yield and nutrient uptake of CRIN Tc-1 and F3 Amazon cocoa seedling in Ibadan. The treatments consist of cocoa pod husk (CPH), Tithonia diversifolia leaves (TD) , combination of CPH and TD (CPH+TD) and NPK fertilizer which were applied to F3 amazon and Tc1 hybrids of cocoa at two levels of mycorrhiza (with and without) inoculation, to supply 10Kg N/ha respectively and laid out in completely randomized design (CRD) in three replicates. All the fertilizer treatments with mycorrhiza were significantly (p<0.05) higher than the treatments without mycorrhiza for N uptake except for NPK and control. Application of sole CPH under mycorrhiza inoculation significantly (p<0.05) enhanced phosphorus uptake in TC1 relative to the control. Potassium uptake was significantly(p<0.05) enhanced by CPH and CPH+TD without mycorrhiza. CPH with mycorrhiza gave the highest leaf and root dry matter yield (DMY) which were significantly higher than the control for Tc-1, while for F3Amazon, TD with mycorrhiza gave the highest root DMY relative to the control. It can therefore be concluded that optimal and sustainable growth and dry matter yield of cocoa seedlings could be achieved by the use of organic fertilizer materials such as TD and CPH in combination with mycorrhiza.

Ionic responses of bean (Phaseolus vulgaris L.) plants under salinity stress and humic acid applications

This study aimed to investigate the effects of different humic acid application methods (control, soil, foliar and soil + foliar) on chlorophyll content, dry matter weight of shoots and roots, concentrations of potassium (K), calcium (Ca) and sodium (Na), and K/Na and Ca/Na ratios of bean plants exposed to increasing salinity levels (0, 50, 100 and 150 mM). The effects of salt damage on shoots and roots of bean plants were significantly differed in humic acid application methods. Chlorophyll content decreased with the increase in salt doses at control and soil application of humic acid, while the decrease in chlorophyll content was lower in foliar application of humic acid. Shoot dry weight was not affected by humic acid applications, while root dry weight increased in soil + foliar application method. Soil + foliar humic acid application caused the highest shoot and root Na concentrations. Shoot Ca (2.61%) concentration in soil + foliar application was significantly higher compared to the other treatments, while the highest Ca concentration in roots (1.55%) was recorded in soil humic acid application method. The highest K concentration in roots was obtained in the control treatment (2.50%) followed by soil + foliar humic acid application (2.48%). The ratios of K/Na and Ca/Na in shoots decreased with the increase in salt application rates. The highest shoot K/Na (1456.1%) and Ca/Na (1274.1%) ratio in humic acid x salt interactions was found in soil application of humic acid without salt treatment. The root and shoot dry matter yield and K and Ca concentrations of the plants indicated that soil+foliar application method has a preventive effect for the plants against the 50 mM salt damage. The results showed that soil+foliar humic acid application in addition to the mineral fertilization required for beans can contribute to the growth and mineral nutrition of the plants under moderate salt stress (50 mM NaCl).

Storage root yield response to leaf harvest of improved and local cassava varieties in DR Congo

ABSTRACT Although cassava is usually grown for its starchy roots, cassava leaves are an important vegetable and protein source in sub-Saharan countries. Eleven cassava mosaic disease (CMD) tolerant and two susceptible varieties were planted in six trials; leaves were harvested at 4, 8 and 11 months after planting (MAP) and storage roots were harvested at 12 MAP. Edible leaf and storage root dry matter yields were strongly affected by variety and interacted with location. Edible leaf yields ranged from 209 to 435 kg ha−1 DM among varieties. Storage root yields ranged from 2540 to 9250 kg ha−1 DM among locations and from 2470 to 7550 kg ha−1 among varieties. Leaf harvest caused 15.8% storage root yield loss. Susceptible varieties produced lowest edible leaf (209 kg ha−1) and storage root (2530 kg ha−1) yields in all locations. Improved varieties suffered storage root yield reductions of 5–25.8%, equivalent to 400–1550 kg ha−1. Edible leaf yield and storage root yield were not correlated. Variety TME419 produced the highest average storage root yields in 3 of 6 locations. The three best leaf producing varieties were not among the best storage root producers, indicating an incompatibility of the two production objectives.