Identification of anoxia resistance genes SUB1A and SNORKEL1 in rice breeding lines

Rice is the second-largest grain crop by area and gross yield. Direct sowing is used in Russia. With direct sowing, flooding is one of the most significant factors causing rice yield losses. On the other hand, flooding can act as a natural herbicide to control weeds. Selection of rice breeding lines tolerant to anaerobic conditions during germination can become a solution to overcome these stress-induced limitations. Identifying molecular markers associated with QTLs or genes controlling flood tolerance during germination allows selecting necessary rice lines more rapidly. The purpose of the current study was to identify the SUB1A and SNORKEL1 deep-sea flood resistance genes in hybrid rice lines. There have been studied 108 hybrid rice breeding lines. Due to PCR analysis using the RM7481 marker specific for the SUB1A gene there has been identified a dominant allele in 35 rice lines. The recombination frequency was 1.4 % (1.4 cM). The dominant allele of the SK1 gene was identified in 13 lines (2.1 % of recombination frequency). Seed germination of rice varieties and hybrid lines varied between 95 % and 100 % under flooding conditions. Hybrid lines with a dominant allele of the SK1 gene and the donor variety Khao Hlan On ranged in height from 111 to 143 mm. Hybrid rice lines with a dominant allele of the SUB1A gene slowed growth under anaerobic conditions. As a result of the study, the selected rice lines are promising samples for further breeding.

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