Introgressed Saltol QTL Lines Improves the Salinity Tolerance in Rice at Seedling Stage

Abstract

Rice is a staple food crop in Asia and plays a crucial role in the economy of this region. However, production of rice and its cultivating areas are under constant threat of soil salinity. A major QTL, Saltol, responsible for salinity tolerance at seedling stage has been mapped on chromosome 1 using Pokkali/IR29 Recombinant Inbred Lines (RIL) population. The present study was aimed to incorporate Saltol Quantitative Trait Loci (QTL) in two high yielding mega rice varieties i.e. Pusa44 and Sarjoo52 through Marker Assisted Backcross Breeding (MABB). To improve the seedling stage salinity tolerance in these cultivars, we introgressed the Saltol QTL from donor parent FL478 a derivative of Pokkali. A total of three backcrosses (BC 3) followed by selfing have led to successful introgression of Saltol QTL. Foreground selection at each breeding cycle was done using micro-satellite markers RM3412 and AP3206 to confirm Saltol QTL. The precise transfer of Saltol region was established using recombinant selection through flanking markers RM493 and G11a. Finally, 10 Saltol near isogenic lines (NILs) of Pusa44 and eight NILs of Sarjoo52 were successfully developed. These NILs (BC 3 F 4) were evaluated for seedling stage salinity under hydroponic system. The NILs PU99,

Effect of different levels of soil salinity on rice seeds blooming, seed thickness and storage level (in the case of Uzbekistan)

“…Placement of laboratory, lysimetric and field experiments in scientific research, calculations, observations were performed using "Methodological manual of the State Commission for Variety Testing of Agricultural Crops" [5] and "Methods of conducting field experiments" [4,8]. Analysis of plant and soil sampling and study of chemical composition was done using "Methods of agrochemical analysis of soil and plants" [6], "accelerated method of assessing samples of rice for resistance to soil salinity" to assess the salt resistance of rice " [3]. The degree of pre-harvest preservation of planted rice plants was calculated by counting the number of seedlings during the full ripening period of the stalk.…”

“…It is important to conduct scientific research on the development and improvement of saline lands in the country, the efficient use of natural resources, the development of rice growing, the further strengthening of the ecological situation, food security [2][3][4][5]9]. Today, the continuous development of agricultural production, further strengthening of food security, efficient use of irrigated lands, including saline lands and waters, creation, selection of new varieties of salt-resistant agricultural crops adapted to local soil, climate and environmental conditions, resource-saving modern technologies are being done towards development of grain and rice in Uzbekistan [1].…”

“…Of course, these disadvantages in seed germination had led to a decline in rice yields. It was stated that a 2% solution of FC in strongly saline soils led to a decrease in seed germination rate and root length and mass [3][4]11]. It was not recommended to use this FC drug in non-saline soils.…”

“…As a result, the living conditions of the plant slow down, development slows down and yields are lost [8,10]. According to Norqulov [5], the first signs of damage caused by salinity were: (1) late germination of seeds; (2) uneven growth or developmental delay [3,7].…”

“…Large seeds have high field germination. Field fertility can vary from 17% to 80% depending on environmental and agrotechnical factors [3][4][5]12]. It can be concluded that no scientific and practical work has been carried out in our country, such as the selection and separation of salt-tolerant varieties of rice, their cultivation in different and different saline conditions and soils.…”