scholarly journals Ca2+/Na+ Ratio as a Critical Marker for Field Evaluation of Saline-Alkaline Tolerance in Alfalfa (Medicago sativa L.)

Agronomy ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 191
Author(s):  
Tian-Jiao Wei ◽  
Chang-Jie Jiang ◽  
Yang-Yang Jin ◽  
Guo-Hui Zhang ◽  
Ming-Ming Wang ◽  
...  
Keyword(s):  
Traditional Method ◽  
Explanatory Power ◽  
Field Evaluation ◽  
Field Conditions ◽  
Stem Length ◽  
Alkaline Salt ◽  
Physiological Indices ◽  
Alkaline Tolerance ◽  
Medicago Sativa L ◽  
Salt Affected Soils

Current indices of saline-alkaline (SA) tolerance are mainly based on the traditional growth and physiological indices for salinity tolerance and likely affect the accuracy of alfalfa tolerance predictions. We determined whether the inclusion of soil alkalinity-affected indices, particularly Ca2+, Mg2+, and their ratios to Na+ in plants, based on the traditional method could improve the prediction accuracy of SA tolerance in alfalfa, determine important indices for SA tolerance, and identify suitable alfalfa cultivars in alkaline salt-affected soils. Fifty alfalfa cultivars were evaluated for their SA tolerance under SA and non-SA field conditions. The SA-tolerance coefficient (SATC) for each investigated index of the alfalfa shoot was calculated as the ratio of SA to non-SA field conditions, and the contribution of SATC under different growth and physiological indices to SA tolerance was quantified based on the inclusion/exclusion of special alkalinity-affected indices. The traditional method, excluding the special alkalinity-affected indices, explained nearly all of the variation in alfalfa SA tolerance, and the most important predictor was the SATC of stem length. The new method, which included these special alkalinity-affected indices, had similar explanatory power but instead identified the SATC of shoot Ca2+/Na+ ratio, followed by that of stem length, as key markers for the field evaluation of SA tolerance. Ca2+, Mg2+, and their ratios to Na+ hold promise for enhancing the robustness of SA-tolerance predictions in alfalfa. These results encourage further investigation into the involvement of Ca2+ in such predictions in other plant species and soil types under more alkaline salt-affected conditions.

scholarly journals Abscisic Acid Priming Creates Alkaline Tolerance in Alfalfa Seedlings (Medicago sativa L.)

Agriculture ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 608
Author(s):  
Tian-Jiao Wei ◽  
Ming-Ming Wang ◽  
Yang-Yang Jin ◽  
Guo-Hui Zhang ◽  
Miao Liu ◽  
...  
Keyword(s):  
Abscisic Acid ◽  
Molecular Mechanisms ◽  
Leaf Damage ◽  
Alkaline Stress ◽  
Acid Pretreatment ◽  
Solution Ph ◽  
Expression Of Genes ◽  
Alkaline Tolerance ◽  
Alkaline Conditions ◽  
Medicago Sativa L

Soil alkalization triggers ion toxicity and osmotic and alkaline (high pH) stresses in plants, damaging their growth and productivity. Therefore, we investigated whether priming with abscisic acid (ABA) increases the tolerance of alfalfa seedlings to alkaline stress, and then examined the underlying molecular mechanisms. Alfalfa seedlings were pretreated with ABA (10 μM) for 16 h and then subjected to alkaline stress using a 15 mM Na2CO3 solution (pH 10.87). Compared with the control, ABA pretreatment significantly alleviated leaf damage and improved the fresh weight, water content, and survival rate of alfalfa seedlings under alkaline conditions. Abscisic acid pretreatment reduced accumulation of reactive oxygen species (ROS), increased activities of the antioxidant enzymes superoxide dismutase (SOD) and peroxidase (POD), maintained higher ratios of K+/Na+, Ca2+/Na+, and Mg2+/Na+, and increased accumulation of proline. In addition, ABA upregulated the expression of genes involved in proline biosynthesis (P5CS) and the sequestration of Na+ in vacuoles (NHX1 and AVP) under alkaline conditions. Abscisic acid priming increased tolerance to alkaline stress by maintaining homeostasis of ROS and metal ions and upregulating osmoprotection and the expression of stress tolerance-related genes.

FIELD EVALUATION OF INSECTICIDES FOR THE CONTROL OF THE EUROPEAN SKIPPER, THYMELICUS LINEOLA (LEPIDOPTERA: HESPERIIDAE), IN QUEBEC

1979 ◽  
Vol 111 (12) ◽  
pp. 1313-1317 ◽  
Author(s):  
Michel Letendre ◽  
Jeremy N. McNeil
Keyword(s):  
Bacillus Thuringiensis ◽  
Larval Mortality ◽  
Field Evaluation ◽  
Field Conditions ◽  
Target Effects

AbstractThe efficacy of seven chemical insecticides, five commercial preparations of Bacillus thuringiensis, and two preparations containing diatom dust were tested against the European skipper, Thymelicus lineola (Ochs.), under field conditions. Satisfactory control was obtained with carbaryl, carbofuran, methomyl, permethrin, trichlorfon, Dipel 45B(=Dipel SC), Dipel WP, Thuricide 26B, Thuricide HPC, and Novabac 3 while dimethoate, chlorpyrifos, and the diatom dusts afforded little or no foliage protection. While larval mortality occurred less rapidly when B. thuringiensis preparations were applied, their use is strongly recommended as they afford the same degree of foliage protection as chemical insecticides and diminish possible undesirable off-target effects.

Field evaluation following two cycles of backcross transfer of somatic embryogenesis to commercial alfalfa germplasm

1993 ◽  
Vol 73 (1) ◽  
pp. 131-137 ◽  
Author(s):  
S. R. Bowley ◽  
G. A. Kielly ◽  
K. Anandarajah ◽  
B. D. McKersie ◽  
T. Senaratna
Keyword(s):  
Somatic Embryogenesis ◽  
Medicago Sativa ◽  
Seed Yield ◽  
Field Experiments ◽  
Field Evaluation ◽  
Growth Characteristics ◽  
Seed Technology ◽  
Artificial Seed ◽  
Medicago Sativa L

For successful application of artificial seed technology to alfalfa (Medicago sativa L.), parental plants must possess the necessary genes for somatic embryogenesis and produce progeny having high commercial value. A backcross procedure was initiated to transfer the ability to form somatic embryos from genotype A70-34, a selection from the cultivar Rangelander, to multiple-pest-resistant alfalfa germplasm. The objectives of this study were to evaluate the growth characteristics and seed yield of the F1; BC1 and BC2 generations to determine if introgression with commercial germplasm had improved the agronomic features of the embryogenic germplasm. This study consisted of two field experiments, each conducted at two locations. One experiment evaluated herbage growth characteristics and herbage production at Elora and Woodstock, Ontario, and the other evaluated seed yield at Elora and Delhi, Ontario. Significant increases in fall regrowth height, leaflet length:width ratio, and seed yield were detected over the cycles of crossing. By the BC2, fall dormancy and leaflet length:width ratio were similar to those in commercial populations. Although improvements in seed yield were detected, the BC2 was inferior in seed yield compared with commercial germplasm, and further introgression and (or) conscious selection for improved seed yield will be required. Through a population backcross procedure, it appears possible to develop commercial alfalfa germplasm capable of in vitro manipulation. Key words: Alfalfa, Medicago sativa L., somatic embryogenesis, artificial seed, backcross

EFFECT OF SEA CROP 16 AND ERGOSTIM ON CROP YIELDS AND PLANT COMPOSITION

1982 ◽  
Vol 62 (3) ◽  
pp. 527-532 ◽  
Author(s):  
UMESH C. GUPTA ◽  
J. A. MacLEOD
Keyword(s):  
Triticum Aestivum ◽  
Pisum Sativum ◽  
Medicago Sativa ◽  
Crop Yields ◽  
Triticum Aestivum L ◽  
Field Conditions ◽  
Plant Composition ◽  
Greenhouse Study ◽  
Pisum Sativum L ◽  
Medicago Sativa L

Experiments were conducted to determine the effect of Sea Crop (SC 16) and Ergostim on the yield and nutrient composition of a few crops. Studies conducted under greenhouse and field conditions showed that the yields of wheat (Triticum aestivum L.) and peas (Pisum sativum L.) were not affected by the addition of SC16. The nitrogen (N) and sulfur (S) concentrations of the two crops were not affected by SC 16, except in the control and SC 16 treatment only where the increases were likely due to a concentration effect, since these two treatments had lower yields. Boron (B) and molybdenum (Mo) concentrations in the plants were significantly affected by B and Mo applications, but not by SC 16. A greenhouse study showed that the yields of alfalfa (Medicago sativa L.) and wheat were not affected by the addition of Ergostim. The addition of Ergostim did not affect the N or S concentration of wheat or three cuts of alfalfa.

The influence of the lucerne bud mite (Eriophyes medicaginis Keifer) on the growth of lucerne

1981 ◽  
Vol 32 (5) ◽  
pp. 773 ◽  
Author(s):  
PM Ridland ◽  
GM Halloran
Keyword(s):  
Medicago Sativa ◽  
Dry Weight ◽  
Stem Length ◽  
Infestation Level ◽  
Axillary Shoots ◽  
Two Temperatures ◽  
Medicago Sativa L ◽  
Extent Of Damage ◽  
Initial Infestation ◽  
Damage Symptoms

The influence of Eriophyes medicaginis on the growth of lucerne (Medicago sativa L.) was studied at four temperatures (15, 20, 25 and 29�C) at an initial infestation level of 10 mites per seedling, and at two temperatures (20 and 29�C) with four initial levels of infestation (2, 5, 10 and 20 mites per seedling). At 25� and 29�C, infestation with 10 mites per seedling significantly reduced dry weight of tops, stem length and the development of axillary shoots within 22 days of infestation. In this period, the numbers of mites increased 16-fold at 29OC, ninefold at 25�C and sixfold at 20�C, but there was no increase at 15�C. The extent of damage caused by mites at 20�C appeared to vary with the differences in growth of the plants under different photoperiods. Under a short photoperiod (10.3 h) where no axillary shoots developed on either infested or control plants, the extent of damage due to mite infestation was much higher than under a longer photoperiod (13.2 h) where axillary shoots developed on all seedlings. Damage symptoms on leaves of infested plants included chlorotic patches (mainly at 20� and 25�C), agate-like banding (29�C) and a waxy mottle (15�C).

scholarly journals Biological Activity of Sumilarv 0.5G against Anopheles gambiae sensu stricto and Anopheles arabiensis in Northern Tanzania

2019 ◽  
Vol 1 (1) ◽  
pp. 35-42
Author(s):  
Eliningaya J. Kweka ◽  
Aneth M. Mahande ◽  
Shandala Msangi ◽  
Subira Sayumwe ◽  
Johnson O. Ouma ◽  
...  
Keyword(s):  
Biological Activity ◽  
Active Ingredient ◽  
Adult Emergence ◽  
Field Evaluation ◽  
Insect Growth Regulator ◽  
Field Conditions ◽  
World Health ◽  
Natural Habitats ◽  
Full Field ◽  
Northern Tanzania

Background: Sumilarv 0.5G (Sumitomo Chemical Co., Ltd., Tokyo, Japan) is a granular insecticide developed for the control of mosquito and fly aquatic stages. The active ingredient is pyriproxyfen (4-phenoxyphenyl (RS)-2-(2 – pyridyloxy) propyl ether), a juvenile hormone analogue that acts as an insect growth regulator. Sumilarv 0.5G functions by inhibition of adult emergence from pupae. In this study, the Tropical Pesticides Research Institute in Tanzania carried out laboratory, semifield, and full-field evaluation on a new candidate of pupicide, Sumilarv 0.5G. The present study, therefore, sought to test the bioefficacy of Sumilarv 0.5G in laboratory, semifield, and full-field conditions in Mabogini, northern Tanzania. Methods: Standard World Health Organization laboratory bioefficacy evaluations of Sumilarv 0.5G and untreated microcosms were prepared and monitored for inhibition of the larvae introduced to the habitats, while field plots were monitored for 5 weeks after the introduction of Sumilarv 0.5G using manufacturer-recommended doses. Results: Sumilarv 0.5G biolarvicide was highly efficacious in its pupicidal effect, with an adult emergence inhibition rate of up to 90% in all conditions. In both laboratory and semifield experiments, the emergence inhibition was dose-dependent, with the lowest adult emergence being recorded in association with the highest Sumilarv 0.5G dose of 0.03 ppm of active ingredient. Under field conditions, the application rate recommended by the manufacturer – 5 mg ai per m2 – reduced the adult emergence rate by 90% to 96% for up to 5 weeks. Conclusion: We demonstrated the long-lasting biological activity of Sumilarv 0.5G under field conditions. Notably, the field efficacy was attained using the recommended dose of 5 mg per m2, thus making it economical to apply this product, which is capable of inhibiting mosquito productivity in natural habitats for longer periods than achieved by existing products, the efficacy of which is usually about 1 week.

scholarly journals Agricultural tractor slippage measurement system using encoders

2021 ◽  
Vol 13 (2) ◽  
pp. 261-271
Author(s):  
Gerónimo García-Rivera ◽  
◽  
Martín Cadena-Zapata ◽  
Juan Antonio López-López ◽  
Gilbert Fresh López-López ◽  
...  
Keyword(s):  
Moisture Content ◽  
Measurement System ◽  
Field Evaluation ◽  
Electronic Equipment ◽  
Field Conditions ◽  
Soil Conditions ◽  
Manual Method ◽  
System Methodology ◽  
Agricultural Tractor

Introduction: Slippage is usually measured with a standard manual method, however, if it is required slippage information inline in extensive areas of cropland, mechanical and electronic equipment have to be developed. Objective: To design, assemble and evaluate (in laboratory and under field conditions) an encoder-based slippage measurement system. Methodology: The system was integrated and tested in the laboratory, where equations were generated to calculate the slippage. The system was installed in an agricultural tractor and its performance was evaluated on an asphalt track and working with tillage implements on various soil conditions. Results: The values obtained with the manual method and the encoder-based method showed very small differences. The results of field evaluation of the system are in congruence with the type of implement and with the moisture content in the soil. This indicates that the measurement of distances by the wheel turns and the calculation of the percentage of slippage are correct. Study limitations: The system was tested in short runs (up to 100 m). Still to be tested in at least 1 ha. Originality: Automated slippage measurement in extended crop areas. Conclusions: The slippage measurement system based on encoders is reliable for automatically measuring the slippage of agricultural tractor in different field conditions.

Biological Activity of Sumilarv 0.5G against Anopheles gambiae sensu stricto and Anopheles arabiensis in Northern Tanzania

2019 ◽  
Vol 1 (1) ◽  
pp. 35-42
Author(s):  
Eliningaya J. Kweka ◽  
Aneth M. Mahande ◽  
Shandala Msangi ◽  
Subira Sayumwe ◽  
Johnson O. Ouma ◽  
...  
Keyword(s):  
Biological Activity ◽  
Active Ingredient ◽  
Adult Emergence ◽  
Field Evaluation ◽  
Insect Growth Regulator ◽  
Field Conditions ◽  
World Health ◽  
Natural Habitats ◽  
Full Field ◽  
Northern Tanzania

Background: Sumilarv 0.5G (Sumitomo Chemical Co., Ltd., Tokyo, Japan) is a granular insecticide developed for the control of mosquito and fly aquatic stages. The active ingredient is pyriproxyfen (4-phenoxyphenyl (RS)-2-(2 – pyridyloxy) propyl ether), a juvenile hormone analogue that acts as an insect growth regulator. Sumilarv 0.5G functions by inhibition of adult emergence from pupae. In this study, the Tropical Pesticides Research Institute in Tanzania carried out laboratory, semifield, and full-field evaluation on a new candidate of pupicide, Sumilarv 0.5G. The present study, therefore, sought to test the bioefficacy of Sumilarv 0.5G in laboratory, semifield, and full-field conditions in Mabogini, northern Tanzania. Methods: Standard World Health Organization laboratory bioefficacy evaluations of Sumilarv 0.5G and untreated microcosms were prepared and monitored for inhibition of the larvae introduced to the habitats, while field plots were monitored for 5 weeks after the introduction of Sumilarv 0.5G using manufacturer-recommended doses. Results: Sumilarv 0.5G biolarvicide was highly efficacious in its pupicidal effect, with an adult emergence inhibition rate of up to 90% in all conditions. In both laboratory and semifield experiments, the emergence inhibition was dose-dependent, with the lowest adult emergence being recorded in association with the highest Sumilarv 0.5G dose of 0.03 ppm of active ingredient. Under field conditions, the application rate recommended by the manufacturer – 5 mg ai per m2 – reduced the adult emergence rate by 90% to 96% for up to 5 weeks. Conclusion: We demonstrated the long-lasting biological activity of Sumilarv 0.5G under field conditions. Notably, the field efficacy was attained using the recommended dose of 5 mg per m2, thus making it economical to apply this product, which is capable of inhibiting mosquito productivity in natural habitats for longer periods than achieved by existing products, the efficacy of which is usually about 1 week.

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