Selection of rice breeding lines for resistance to biotic and abiotic stresses.

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.

Heritability and amylose content in hybrid lines of late-generation rice with colored pericarp.

Improving grain quality in rice breeding is one of the main tasks. This concerns the creation of rice varieties with colored pericarp uncommon in the Republic of Kazakhstan, and the assessment of its quality is an important stage of breeding. Rice with colored pericarp is an important dietary crop, more useful for the human body than white rice. Regardless of the type of rice, the amount of amylose in rice grain is a crucial indicator that determines the quality of rice. The paper presents the results of electrophoretic separation of spare grain proteins of rice hybrids and dihaploids with colored pericarp and their parent forms obtained as a result of the hybridization of varieties with colored pericarp (Black Rice (China), Mavr (Russia), and Yir 5815 (Ukraine)) with white rice varieties zoned in Kazakhstan. The hybridization of the rice varieties with colored pericarp with white rice varieties was carried out to obtain rice varieties with colored pericarp oriented to the soil and climate of Kazakhstan. Analyzing the results of electrophoresis and the amount of amylose, it was found that hybrid lines differed in amylose content. One of the studied hybrids was high in amylose, four had a medium amylose content, ten had a low amylose content, three had a very low amylose content, and six were glutinous. According to the results of electrophoretic separation of spare rice grain proteins, the spectrum of the enzyme determining amylose was detected in five hybrids, which corresponds to the results of spectrophotometric determination of amylose: high amylose in one hybrid and medium amylose content in four. The results show that the hybrids obtained as a result of hybridization are true hybrids and as a result of long-term selection, the amylose content in the F7-F8 hybrids stabilized. The hybrids can be used in further breeding of rice with colored pericarp.