Analysis of blast resistance genes in Longliangyou and Jingliangyou hybrid rice varieties

Abstract

<p id="C3">Longke 638S and Jing 4155S, developed by Yuan Longping High-Tech Agriculture Co., Ltd. in 2014, were two thermo-sensitive genic male sterile (TGMS) lines with disease resistance, high grain quality and combining ability for producing mid-season<italic> indica</italic> hybrid rice. In this study, we analyzed the blast resistance evaluation data from the regional trials of the Longliangyou and Jingliangyou hybrid rice varieties approved by the state from 2015 to 2019. Meanwhile, to provide theoretical basis for distribution and further improvement of these hybrid rice varieties, a genotyping panel containing 16 rice blast resistance (<italic>R</italic>) genes based on KASP (Kompetitive Allele-Specific PCR) technology was developed and used for molecular detection of these hybrid rice varieties. The results showed that 43.92% of Longliangyou and Jingliangyou hybrid rice varieties conferred moderate resistance to high resistance to blast disease. The mean value of integrated disease index (IDI) and highest scale of panicle blast severity (HSPBS) was 3.3 and 4.7, respectively. These hybrid rice varieties carried different number of <italic>R</italic> genes, ranging from 3 to 7. The average number of <italic>R</italic> genes in each variety was 5.1. The distribution frequency of the five genes including <italic>Pia</italic>, <italic>Pita</italic>, <italic>Pi2</italic>, <italic>Pi5</italic>, and <italic>Piz </italic>were higher by more 50%, among which, it was 100% for <italic>Pia</italic> gene. In contrast,<italic> Pi9</italic>, <italic>Pi35</italic>,<italic> Pi36</italic>, and <italic>Pb1</italic> genes were not detected in Longliangyou and Jingliangyou hybrid rice varieties. With the increase of the number of <italic>R</italic> genes in the varieties, the mean values of IDI and HSPBS were generally decreased. In conclusion, we suggested that introduction of <italic>Pi9 </italic>into Longke 638S and Jing 4155s might lead to the further improvement of blast resistance of Longliangyou and Jingliangyou hybrid rice varieties.