Identification of Saltol QTL in the breeding rice samples

One of the main problems in most of the world rice-growing regions is soil salinity. Rice is considered a saline sensitive crop, especially at the early stages of development and in the period of maturity. In the Rostov region, rice is grown in the south-eastern parts, where there are currently difficulties with the operation of the existing reclamation facilities. The problem of saline soils for this region is especially urgent, since a significant part of the arable lands has alkali complexes. In order to return the saline lands into exploitation, it is necessary to develop salt tolerant varieties, which, under crop rotation and maintenance, can contribute to soil desalinization. Due to the difficulty of determining salt tolerance only by estimating the phenotype, it is necessary to use molecular markers associated with this trait. Thus, the purpose of the current work was to identify one of the main Saltol QTL in breeding rice samples of the eighth generation (F8) obtained from hybridizing the donor variety NSYC Rc106 with Russian varieties. For that purpose, there have been used such marker-assisted selection methods as DNA isolation, polymerase chain reaction (PCR), electrophoresis on 2% agarose gels, gels’ coloring in ethidium bromide solution, photography in ultraviolet light and evaluation of the obtained electrophoregrams. As a result of the study of 398 breeding rice samples, there have been identified 67 samples with the functional allele of Saltol QTL (6865/3, 6874/2, Don 7343/4, Don 7343/5, Don 7343/6, Don 7343/7, Don 7343/8, Don 7343/9, Don 7343/10, Don 7337/1, Don 7337/3, Don 7337/4, Don 7337/5, Don 7337/6, Don 7337/7, Don 7337/8, etc.). There have been recommended to use these samples in the further breeding process in order to develop new salinity resistant rice varieties.

Tailoring Next Generation Plant Growth Promoting Microorganisms as Versatile Tools beyond Soil Desalinization: A Road Map towards Field Application

Plant growth promoting bacteria (PGPB) have been the target of intensive research studies toward their efficient use in the field as biofertilizers, biocontrol, and bioremediation agents among numerous other applications. Recent trends in the field of PGPB research led to the development of versatile multifaceted PGPB that can be used in different field conditions such as biocontrol of plant pathogens in metal contaminated soils. Unfortunately, all these research efforts lead to the development of PGPB that failed to perform in salty environments. Therefore, it is urgently needed to address this drawback of these PGPB toward their efficient performance in salinity context. In this paper we provide a review of state-of-the-art research in the field of PGPB and propose a road map for the development of next generation versatile and multifaceted PGPB that can perform in salinity. Beyond soil desalinization, our study paves the way towards the development of PGPB able to provide services in diverse salty environments such as heavy metal contaminated, or pathogen threatened. Smart development of salinity adapted next generation biofertilizers will inevitably allow for mitigation and alleviation of biotic and abiotic threats to plant productivity in salty environments.

Artificial Macropores with Sandy Fillings Enhance Desalinization and Increase Plant Biomass in Two Contrasting Salt-Affected Soils

Salt accumulation in topsoil is a widespread restricting factor that limits agricultural production and threatens food security in arid and semi-arid regions. However, whether this upward enrichment was suppressed by macropores was less documented. Therefore, artificial macropores with sandy fillings (AMSF) method was proposed in this study. Soil column experiments showed a significant improvement of saturated hydraulic conductivity (Ks) by more than 260% under artificial macropore treatment. Freshwater irrigation was conducted to monitor the short-term water and salt movement. This research aimed at evaluating the potential benefit of AMSF method on soil desalinization in coastal farmland of northern China. The results demonstrated that downward movement of soil water was stimulated in AMSF method, accordingly, washing more salt ions out of top rooting zone. Particularly, 10 cm or more macropore depth treatments of AMSF method enhanced total desalinization by 52.1% to 176.6% in 0–30 cm soil layer, in comparison to the control group without macropore. Subsequent observations for alfalfa showed higher biomass by 20.8% under 15 cm macropore depth. The results here provided an exploration demonstration to pursue these studies with the ultimate goal of optimizing application strategies for amendment in coastal salt-affected lands of northern China.

INFLUENCE OF FERTIGATION ON SOIL SALINATION

The salt state has a noticeable effect on the physical and water properties of the soil. That is why the distribution of its water-physical properties along the profile and in space in territories with different soil-climatic, hydrological and hydrochemical conditions should be individual. This is due, on the one hand, to the fact that water is directly involved in the processes of transfer and distribution of salts. On the other hand, the main parameters of the processes of moisture and salt transfer directly depend on the physical properties of the soil, which change under the influence of soluble salts. We have assessed the effect of fertigation on the physicochemical properties of the soil. Four fertigations with different salinity levels were tested. The influence of precipitation on soil desalinization through salt leaching was controlled by comparing changes in soil electrical conductivity during and after the growing season. To measure the studied characteristics, sensors of the 5TE type were used, which independently determine three indicators - the volumetric water content (VWC) by measuring the dielectric constant of the medium based on capacitive / frequency technology, temperature and EC. The stability of soil aggregates was also measured as an indicator of soil degradation. The electrical conductivity of the soil during pre-sowing (or after sowing) treatment was higher than at the end of the growing season. Experimental studies were carried out in the western part of the city of Prague on the campus of the Czech University of Life Sciences with geographic coordinates 50 ° 8'N and 14 ° 23'E. The altitude is 286 m, the average annual air temperature is 9.1 ° C, the amount of precipitation is 495 mm. The soil is loamy chernozem with a content of 22.0 ... 32.5% sand, 39.5 ... 54.0% silt and 22.0 ... 28.0% clay. The limiting field moisture capacity of the soil and the moisture content of stable wilting are 34 and 21%, respectively. It was found that fertigation in the short term is not harmful to the soil in the presence of sufficient precipitation

Study of the reclamed effect of the “Biosolvent” preparation on alcaline soils when washing and irrigating

Purpose: to study the effect of the desalinator “Biosolvent” on the processes of soil desalinization during the washing and vegetative irrigation. Materials and methods. The research was carried out in Syrdarya region of Uzbekistan at experimental sites. The objects of research are saline soils of irrigated fields under cotton. Field observations and soil analyzes were carried out according to generally accepted methods: granulometric composition – by sedimentation method, salinization – by electrical conductivity and water extract, phenological observations – by the SoyuzNIKHI method. Statistical processing was performed in Excel. Results: when spraying soil of strong and medium salinity with 10% Biosolvent preparation before washing and watering cotton, the leaching of ions toxic to plants is higher compared to conventional washing, more harmful ions are washed out: chlorine by 35–42 %, sulfates by 13–16 %, calcium by 21–28 %, sodium by 21–23 %. When treating the surface of furrows with a 10% solution before watering cotton, a more significant decrease in the content of harmful salts was also found than with conventional irrigation. Salts were washed out along the treated furrows by 18–23 % more, and chlorine, sulfate and calcium ions, respectively, by 17, 18 and 14 %. As a result of improved conditions in the root zone of cotton, an increase in yield of 7.5 c/ha was obtained. Conclusions. To increase the efficiency of washing saline soils and regulate the salinity of the root layer of soil during the growing season, it is advisable to apply preliminary spraying of the soil with a 10% solution of the “Biosolvent” preparation. The use of Biosolvent in comparison with traditional technologies contributes not only to a decrease in soil salinity, positive changes in chemical composition of salts in the soil, but also to an increase in cotton yield.

Modern Technologies of Alkalized and Sodic Soils Reclamation

The technology of desalination of fine-textured soils using deep tillage, leaching operations and chemical reclamation agents includes the calculation of doses of ameliorants and leaching requirements, methods and timing of reclamation, soil treatment, selection of crops, and the need for fertilizers on reclamation lands. The stages of preparation of the fields before the application of ameliorants are reviewed. Initially, the fields are divided into lots, the location of loose ameliorants clamps is determined. The options for overall and selective land reclamation are considered. When conducting selective reclamation, it is necessary to locate the solonetzic spots and mark them with range poles. The options for cultivating the soil of irrigated lands characterized by increased density of the subsurface soil horizon of more than 1.4 t/m3 are reviewed. The most pressed are the solonetzic soils with a poor structure or without it. The most preferred methods of cultivating degraded soils (deep loosening or plowing) are identified, which are one of the necessary techniques to provide the greatest depth, degree and speed of soil desalinization. The options for leaching of chloride-sulfate loamy soils, chloride-sulfate salinization and soda salinization are considered.

The effect of irrigation of cotton on the salt regime of the soil

The aim of the research is to study the effect of irrigation on the salt regime of the soil at various experimental sites. The production of cotton fiber with high technological quality is closely connected with the salt regime of the soil, because the excessive content of readily soluble salts in soils leads to a decrease in the yield of cotton. Studies have shown that the regime of irrigation of fine-fiber cotton exerts a noticeable influence on the change in the salt regime of soils. It has been established that in the irrigated lands of the Karshi step, which are susceptible to salinity to a weak degree, cotton should be used every year as a mandatory agrotechnical method for pre-sowing emergency preventive irrigation with the norms of 1200...1500 m3/ha. The effect of soil desalinization achieved by these waterings should be secured by applying optimal irrigation regimes for fine-fiber cotton during its growing season in conjunction with other agrotechnical measures carried out by intensive technology. With the introduction of such interlinked agro-meliorative measures, a precondition is created for maximum prevention of the movement of water-soluble salts from the lower, more saline layers to the upper ones.