GENETIC VARIATION WITHIN CASSAVA GERMPLASM IN RESPONSE TO POTASSIUM

2000 ◽  
Vol 36 (3) ◽  
pp. 323-334 ◽  
Author(s):  
M. A. EL-SHARKAWY ◽  
L. F. CADAVID
Keyword(s):  
Low Fertility ◽  
Hydrocyanic Acid ◽  
Root Production ◽  
Shoot Biomass ◽  
Human Consumption ◽  
Total Biomass ◽  
Nitrogen And Phosphorus ◽  
High K ◽  
Use Efficiency ◽  
Low K

As cassava is grown mostly by small resource-limited farmers throughout the tropics on low-fertility soils with little fertilization and, due to the large potassium (K) export in harvested roots, genotypes that tolerate low-K soils and respond to K fertilization are warranted. The objective of this study was to evaluate cassava germplasm and identify such genotypes.Fourteen cultivars of cassava (Manihot esculenta) selected from the core germplasm at CIAT were grown under rainfed conditions for ten months over five consecutive seasons in Inceptisols either with no K application or with 50, 100 or 200 kg K ha−1 applied annually together with adequate nitrogen and phosphorus. All cultivars responded to K application both in terms of root and shoot biomass with the highest yields obtained by CM 507-37 and M Ven 25 in the absence of K application and at high K levels. These cultivars had the highest adaptation indices to low K and the highest K use efficiency for total biomass production. CM 507-37 had the highest K use efficiency for root production at all K levels. Thus, it is desirable to use this material for breeding cassava which is adapted to low-K soils and is able to respond to fertilizer application. However, because of the high hydrocyanic acid (HCN) content in their roots, these cultivars should be crossed with genotypes that are low in HCN, such as HMC-1 and M Cub 74, in order to select lines with both high K use efficiency and low HCN for fresh cassava consumption. Root HCN contents were significantly reduced by application of K across all cultivars. Application of K fertilizer to low-K soils is warranted to minimize health hazards when fresh cassava is used for human consumption.

scholarly journals Effects of High Potassium and Low Temperature on the Growth and Magnesium Nutrition of Different Tomato Cultivars

HortScience ◽  
2018 ◽  
Vol 53 (5) ◽  
pp. 710-714 ◽  
Author(s):  
Huixia Li ◽  
Zhujun Chen ◽  
Ting Zhou ◽  
Yan Liu ◽  
Sajjad Raza ◽  
...  
Keyword(s):  
Low Temperature ◽  
Shoot Biomass ◽  
Total Biomass ◽  
High Potassium ◽  
Hydroponic Experiment ◽  
Root Shoot Ratio ◽  
High K ◽  
Significant Difference ◽  
Tomato Cultivars ◽  
K Concentration

The interaction between potassium (K) and magnesium (Mg) in plants has been intensively studied. However, the responses of different tomato (Solanum lycopersicum L.) cultivars to high K levels at low temperatures remained unclear. Herein, a complete randomized hydroponic experiment was conducted to evaluate the effects of temperature (25 °C day/18 °C night vs. 15 °C day/8 °C night) and K concentrations (156 mg·L−1 vs. 468 mg·L−1) on the growth and Mg nutrition of tomato cultivars Gailiangmaofen (MF) and Jinpeng No. 1 (JP). Compared with the control temperature (25 °C day/18 °C night), the low temperature decreased total biomass, shoot biomass, and Mg uptake in shoot by 17.3%, 24.1%, and 11.8%, respectively; however, the root/shoot ratio was increased. High K had no significant effect on plant growth or biomass compared with the control K concentration (156 mg·L−1); however, Mg concentrations and uptake in shoot were significantly lower under high-K treatment. Significant difference was observed for K uptake, but not for Mg uptake, between the two cultivars. There was no significant interaction between temperature and high K on Mg uptake of tomato, so a combined stress of low temperature and high K further inhibited Mg uptake and transport. Low temperature and high K increased the risk of Mg deficiency in tomato.

Fine-root biomass and nutrient cycling in Aristida stricta in a North Carolina coastal plain savanna

1984 ◽  
Vol 62 (4) ◽  
pp. 823-829 ◽  
Author(s):  
Kathryn A. Saterson ◽  
Peter M. Vitousek
Keyword(s):  
North Carolina ◽  
Coastal Plain ◽  
Root Biomass ◽  
Fine Root ◽  
Fine Root Biomass ◽  
Low Fertility ◽  
Root Production ◽  
Nitrogen And Phosphorus ◽  
Different Tissues ◽  
Slow Turnover

Seasonal changes in total fine-root biomass and the allocations of nitrogen and phosphorus to roots, root crowns, and leaves of Aristida stricta were measured on a North Carolina coastal plain savanna. Total fine-root biomass was determined from sequential root cores taken over 12 months. Total root biomass decreased from spring to late fall and then increased in winter. Root production and turnover estimates indicate that this low-fertility savanna has a relatively large root biomass and slow turnover. The pattern of allocation of biomass, nitrogen, and phosphorus to different tissues of Aristida stricta indicates that throughout the year the greatest percentage of biomass and nutrients is in roots.

scholarly journals Potassium Fertilisation Is Required to Sustain Cassava Yield and Soil Fertility

Agronomy ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1103
Author(s):  
Ming Fung Chua ◽  
Laothao Youbee ◽  
Saythong Oudthachit ◽  
Phanthasin Khanthavong ◽  
Erik J. Veneklaas ◽  
...  
Keyword(s):  
Low Fertility ◽  
Root Yield ◽  
Storage Roots ◽  
High Background ◽  
Yield Increase ◽  
Cropping Season ◽  
High K ◽  
Low K ◽  
Positive Effect ◽  
Early Harvest

Cassava is often grown in low-fertility soils and has a reputation for having modest nutrient requirements. The storage roots that are harvested, however, contain relatively large amounts of potassium (K). We carried out a field experiment in Laos to determine the growth response to K fertiliser and to examine the field’s K balance over the cropping season. Four different rates of K (0-40-80-120 kg K2O equivalents ha−1) were applied to cassava variety Rayong11. Harvests were done at 8 and 10 months after planting, when the crop was at early and full maturity respectively, to assess if any benefits for productivity or K balance could be achieved by early harvest. We found a positive effect of K fertiliser (up to 39% yield increase compared to no K fertiliser at early harvest, 21% at late harvest) and a positive effect of late harvest (on average a 35% increase compared to early harvest) on cassava root yield. Low-K crops benefited more from a late harvest. At 10 months, the harvested cassava contained 99–142 kg K ha−1, indicating that there was a net removal of K from the fields, even at high K fertilisation levels. This experiment was carried out in comparatively fertile soil with relatively high background K levels, yet, yield benefits of K fertilisation were observed and soil K reserves were depleted by the harvest. It can be concluded that K fertilisation of cassava is advisable for better yields and to avoid progressive depletion of the soil K capital.

RESPONSE OF CASSAVA TO PROLONGED WATER STRESS IMPOSED AT DIFFERENT STAGES OF GROWTH

2002 ◽  
Vol 38 (3) ◽  
pp. 333-350 ◽  
Author(s):  
M. A. El-Sharkawy ◽  
L. F. Cadavid
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Root Biomass ◽  
Nitrogen Concentration ◽  
Nutrient Use Efficiency ◽  
Root Production ◽  
Shoot Biomass ◽  
Area Index ◽  
Nutrient Use ◽  
Use Efficiency

A two-year field trial was conducted to study the effects of prolonged water stress on cassava (Manihot esculenta) productivity, and on nutrient uptake and use efficiency. Four contrasting cultivars were supplied with adequate fertilization and watering, except when water was excluded by covering the soil with plastic sheets for different periods, depending on treatment: from two to six months, four to eight months, or from six to twelve months after planting (early, mid-season and terminal stress respectively). Sequential harvests were made at 2, 4, 6, 8 and 12 months after planting to determine leaf area index and shoot and root biomass. At final harvest, nitrogen, phosphorus, potassium, calcium and magnesium concentrations in shoots and storage roots were determined.During both early and mid-season stress, leaf area index and shoot and root biomass were significantly smaller than those in the controls across all cultivars. After recovery from stress, leaf area index was greatly enhanced with less dry matter allocated to stems, and root yields approached those in the controls. One cultivar, CMC 40, had greater final root yield under stress treatments. Nutrient concentration in roots and shoots was less in all cultivars with early stress and resulted in higher nutrient use efficiency in all elements for root production. The same trend was observed under mid-season stress, except for nitrogen concentration, which remained unchanged.Terminal stress did not affect leaf area index, but reduced the shoot biomass in all cultivars. Final root yields were smaller than those in the controls except for CMC 40 whose final root yield was greater under stress. Nitrogen concentration was greater in root biomass but less in shoot biomass of all cultivars, resulting in lower nitrogen–use efficiency for root production. Across cultivars, only potassium- and magnesium-use efficiencies were greater than in the controls. CMC 40 was the only cultivar with consistently greater use efficiency of nitrogen, phosphorus, potassium, calcium and magnesium for root production under terminal stress. This higher nutrient use efficiency was due, mainly, to a greater root production rather than to smaller nutrient concentration. This cultivar is suitable as a gene source for improving cassava in order to maximize root production per unit nutrient extracted under stressful environmental conditions.

scholarly journals Opportunities for Increased Nitrogen Use Efficiency in Wheat for Forage Use

Plants ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1738
Author(s):  
Nirmal Sharma ◽  
Raquel Schneider-Canny ◽  
Konstantin Chekhovskiy ◽  
Soonil Kwon ◽  
Malay C. Saha
Keyword(s):  
Nitrogen Use Efficiency ◽  
Crude Protein ◽  
Nitrogen Nutrition ◽  
N Uptake ◽  
N Fertilization ◽  
Shoot Biomass ◽  
Total Biomass ◽  
Strong Positive Correlation ◽  
Nitrogen Use ◽  
Use Efficiency

Wheat is a major cool-season forage crop in the southern United States. The objective of this study is to understand the effect of nitrogen (N) fertilization on wheat biomass yield, quality, nitrogen use efficiency (NUE), and nitrogen nutrition index (NNI). The experiments were conducted in a greenhouse and a hoop house in a split-plot design, with three replications. Twenty wheat cultivars/lines were evaluated at four N rates (0, 75, 150, and 300 mg N.kg−1 soil) in the greenhouse and (0, 50, 100, and 200 mg N.kg−1 soil) in the hoop house. In general, high-NUE lines had lower crude protein content than the low-NUE lines. None of the cultivars/lines reached a plateau for biomass production or crude protein at the highest N rate. The line × N rate interaction for NUE was not significant in the greenhouse (p = 0.854) but was highly significant in the hoop house (p < 0.001). NNI had a negative correlation with NUE and biomass. NUE had strong positive correlations with shoot biomass and total biomass but low to moderate correlations with root biomass. NUE also had a strong positive correlation with N uptake efficiency. Lines with high NUE can be used in breeding programs to enhance NUE in wheat for forage use.

Electron Probe Analysis of Vertebrate Smooth Muscle: Distribution of Ca and Ci

1976 ◽  
Vol 34 ◽  
pp. 334-335 ◽  
Author(s):  
Avril V. Somlyo ◽  
H. Shuman ◽  
A.P. Somlyo
Keyword(s):  
Smooth Muscle ◽  
Electron Probe ◽  
Preliminary Report ◽  
Cell Damage ◽  
Electron Probe Analysis ◽  
Perinuclear Space ◽  
Probe Analysis ◽  
High K ◽  
Low K ◽  
Initial Results

This is a preliminary report of electron probe analysis of rabbit portal-anterior mesenteric vein (PAMV) smooth muscle cryosectioned without fixation or cryoprotection. The instrumentation and method of electron probe quantitation used (1) and our initial results with cardiac (2) and skeletal (3) muscle have been presented elsewhere.In preparations depolarized with high K (K2SO4) solution, significant calcium peaks were detected over the sarcoplasmic reticulum (Fig 1 and 2) and the continuous perinuclear space. In some of the fibers there were also significant (up to 200 mM/kg dry wt) calcium peaks over the mitochondria. However, in smooth muscle that was not depolarized, high mitochondrial Ca was found in fibers that also contained elevated Na and low K (Fig 3). Therefore, the possibility that these Ca-loaded mitochondria are indicative of cell damage remains to be ruled out.

Contrasting yield formation characteristics in two super-rice hybrids that differ in growth duration

2021 ◽  
pp. 1-10
Author(s):  
Min Huang ◽  
Zui Tao ◽  
Tao Lei ◽  
Fangbo Cao ◽  
Jiana Chen ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Biomass Production ◽  
Field Experiments ◽  
Crop Improvement ◽  
Total Biomass ◽  
Growth Duration ◽  
Area Index ◽  
Rice Hybrid ◽  
Use Efficiency ◽  
Yield Formation

Summary The development of high-yielding, short-duration super-rice hybrids is important for ensuring food security in China where multiple cropping is widely practiced and large-scale farming has gradually emerged. In this study, field experiments were conducted over 3 years to identify the yield formation characteristics in the shorter-duration (∼120 days) super-rice hybrid ‘Guiliangyou 2’ (G2) by comparing it with the longer-duration (∼130 days) super-rice hybrid ‘Y-liangyou 1’ (Y1). The results showed that G2 had a shorter pre-heading growth duration and consequently a shorter total growth duration compared to Y1. Compared to Y1, G2 had lower total biomass production that resulted from lower daily solar radiation, apparent radiation use efficiency (RUE), crop growth rate (CGR), and biomass production during the pre-heading period, but the grain yield was not significantly lower than that of Y1 because it was compensated for by the higher harvest index that resulted from slower leaf senescence (i.e., slower decline in leaf area index during the post-heading period) and higher RUE, CGR, and biomass production during the post-heading period. Our findings suggest that it is feasible to reduce the dependence of yield formation on growth duration to a certain extent in rice by increasing the use efficiency of solar radiation through crop improvement and also highlight the need for a greater fundamental understanding of the physiological processes involved in the higher use efficiency of solar radiation in super-rice hybrids.

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