Salinity has a significant impact on rice production in coastal, arid and semi-arid areas in many countries, including countries growing temperate rice, such as Kazakhstan. Recently, the complete genomes of 3000 rice accessions were sequenced through the 3 K rice genome project, and this set included 203 temperate japonica rice accessions. To identify salinity-tolerant germplasm and related genes for developing new salinity-tolerant breeding lines for the temperate japonica rice growing regions, we evaluated the seedling stage salinity tolerance of these sequenced temperate japonica rice accessions, and conducted genome-wide association studies (GWAS) for a series of salinity tolerance related traits. There were 27 accessions performed well (SES < 5.0) under moderate salinity stress (EC12), and 5 accessions were tolerant under both EC12 and EC18. A total of 26 QTLs were identified for 9 measured traits. Eleven of these QTLs were co-located with known salinity tolerance genes. QTL/gene clusters were observed on chromosome 1, 2, 3, 6, 8 and 9. Six candidate genes were identified for five promising QTLs. The alleles of major QTL Saltol and gene O S HKT1;5 (SKC1) for Na+/K+ ratio identified in indica rice accessions were different from those in the temperate japonica rice accessions used in this study. Salinity tolerant temperate japonica rice accessions were identified in this study, these accessions are important resources for breeding programs. SNPs located in the promising QTLs and candidate genes could be used for future gene validation and marker assisted selection. This study provided useful information for future studies on genetics and breeding of salinity tolerance in temperate japonica rice.

Due to the environment pollution by cadmium (Cd) near industrial metallurgic factories and the widespread use of phosphorus fertilizers, the problem of toxic Cd effect on plants is well discussed by many authors, but the phytotoxicity of Cd under iron (Fe) deficiency stress has not been sufficiently studied. The aim of the work was to study comprehensively the effect of Cd under Fe deficiency conditions on physiological, biochemical, and anatomical parameters of rice varieties, to identify varietal differences in plant response to the effect of double stress. Relative resistance and sensitivity to the joint effect of Cd and Fe deficiency stress rice varieties have been identified. Double stress decreased a linear growth and biomass accumulation of roots and shoots (by 36‐50% and 33‐46% and 32‐56% and 32‐48%, accordingly), content of photosynthetic pigments (Chla, Chlb, and carotenoids by 36‐51%, 32‐47%, and 64‐78%, accordingly), and relative water content (by 18‐26%). Proline content increased by 28‐103% in all rice varieties, but to a lesser extent in sensitive varieties. The thickness of the lower and upper epidermis and the diameter of vascular bundles of leaves decreased by 18‐50%, 46‐60%, and 13‐48%, accordingly. The thickness of the root endodermis and exodermis and diameter of the central cylinder mainly decreased. The thickness of the exodermis increased slightly by 7%, and the diameter of the central cylinder remained at the control level in resistant Madina variety while in sensitive Chapsari variety, these indicators decreased significantly by 50 and 45%, accordingly. Thus, the aggravation of adverse effect of Cd under Fe deficiency conditions and the varietal specificity of plants’ response to double stress were shown. It creates the need for further study of these rice varieties using Fe to identify mechanisms for reducing the toxic effect of Cd on plants as well as the study of Fe and Cd transporter genes at the molecular level.

In vitro androgenesis is a unique model for producing homozygous doubled haploid plants. The use of haploid biotechnology accelerates to obtain of doubled haploid plants, which is very important in rice breeding. The purpose of this work is to improve the production of doubled haploids in rice anther culture in vitro and selection of doubled haploid plants with valuable traits. The study the influence of nutrient media on the production of calli and plant regeneration processes in anther culture of 35 rice genotypes was revealed a significant influence of nutrient media on callus production. It was shown that the addition to culture medium phytohormones ratio with high level of cytokinin (5.0 mg/L BAP) and a low level of auxin (0.5 mg/L NAA), supplemented with amino acid composition promotes high production of green regenerated plants (68.75%) compared to albino plants (31.25%). As a result, doubled haploid lines of the glutinous variety Violetta were selected, which characterized by a low amylose content variation (from 1.86 to 2.80%). These doubled haploids are superior to the original variety in some yield traits and represent valuable breeding material.

The aim of this paper was to study the effect of plant growth regulators on callus induction and in vitro morphogenesis using various explants of Paulownia tomentosa to develop an efficient plant regeneration protocol. Different plant organ sections (leaves, apical shoot tips, petals, nodes, and internodes) were cultured as explants to identify the best in vitro explants responsive to callus induction and plant regeneration. Explants were cultivated on MS media supplemented with different concentrations of plant growth regulators (TDZ (Thidiazuron), BAP (6-Benzylaminopurine), kinetin, and NAA (1-Naphthaleneacetic acid). It was discovered that the addition of TDZ and NAA stimulated the induction of somatic embryogenesis. It was discovered that the MS medium with the combination of plant growth regulators BAP (35.5 µM) and NAA (5.4 µM) with the addition of 30.0 g/L maltose, 500.0 mg/L casein hydrolysate, and 250.0 mg/L L-proline was optimal for callus induction and multiple plant regeneration. The study of the regenerative capacity of various explants of Paulownia tomentosa in vitro showed that plant regeneration depends on the type of explant, and occurs in both ways, indirectly, through the formation of callus tissues and directly on the explant, without callus formation. As a result of this study, the efficient reproducible protocol of embryogenic callus formation and multiple shoot induction in vitro of Paulownia tomentosa was developed. This system provides a clear increase in the frequency of plant regeneration from 36.3 ± 3.4% to 38.6 ± 2.3% per embryogenic callus from leaves and apical shoot tips, respectively.

Rice (Oryza sativa L.) grown in many countries around the world with different climatic conditions and a huge number of environmental stresses, both biotic (fungi, bacteria, viruses, insects) and abiotic (cold, drought, salinity) limit rice productivity. In this regard, breeders and scientists are trying to create rice lines that are resistant to multiple stresses. The aim of this work was to screen and select cold and blast resistant rice breeding lines (RBLs) using molecular markers. Molecular screening of RBLs and parental varieties to cold tolerance was carried out using markers RM24545, RM1377, RM231 and RM569 associated with QTLs (qPSST-3, qPSST-7, qPSST-9). It was discovered that the presence of three QTLs characterizes the cold resistance of studied genotypes, and the absence of one of them leads to cold sensitivity. As a result, 21 cold-resistant out of the 28 studied RBLs were identified. These cold resistant 21 RBLs were further tested to blast resistance using markers Pi-ta, Pita3, Z56592, 195R-1, NMSMPi9-1, TRS26, Pikh MAS, MSM6, 9871.T7E2b, RM224 and RM1233. It was revealed that 16 RBLs from 21 studied lines contain 5-6 blast resistance genes. In accordance with the blast resistance strategy, the presence of 5 or more genes ensures the formation of stable resistance to Magnaporthe oryzae. Thus, 16 lines resistant to multiple stresses, such as cold and blast disease were developed. It should be noted that 6 of these selected lines are high-yielding, which is very important in rice breeding program. These RBLs can be used in breeding process as starting lines, germplasm exchange as a source of resistant genes for the development of new rice varieties resistant to multiple stress factors.