关键词: 水稻, 镉胁迫, 萌芽期, QTL

Abstract: Rice is one of the most important food crops in the world. At present, there is a problem of heavy metal pollution in agricultural land, but the tolerance of rice to heavy metals such as cadmium (Cd) is low, which affects the yield and quality of rice. Mapping quantitative trait loci (QTLs) related to Cd tolerance in rice is of great significance for guiding the breeding of Cd tolerance in rice. To explore Cd stress related genes, 124 backcross recombinant inbred ines (BILs) derived from Japonica rice 02428 and Indica rice Changhui 891 were used as materials to analyze the root length and bud length of rice at germination stage, and to locate QTLs related to Cd stress at germination period. The results showed that the root length and bud length of 02428 and Changhui 891 were significantly inhibited under Cd stress (P<0.01), and the inhibition of Cd on root length was stronger than that of bud length. Five QTLs related to Cd stress were detected by QTL analysis: qCdBL3, qCdRL7, qCdBL8.1, qCdBL8.2 and qCdBL9, which were located on chromosome 3, 7, 8, 8 and 9 of rice, respectively, with a contribution rate of 6.45%~19.46%. Among them, qCdBL3, qCdBL8.1, qCdBL8.2 and qCdBL9 were related to bud length, and qCdRL7 was related to root length. At the same time, two  QTLs affecting root length and bud length were detected under control conditions (aqueous solution): qCKBL8 and qCKRL4, which were located on chromosome 8 and 4, respectively, with the contribution rates of 10.53% and 1089%. Comparison showed that QTLs controlling root length or bud length of rice in germination stage were different between control and Cd treatment, which indicated that the genetic mechanism controlling root length and bud length of rice under Cd stress might be different from that under non-Cd stress. The results provided a reference for cloning Cd-tolerant genes and breeding new Cd-tolerant rice varieties.

Key words: rice, cadmium stress, germination period, QTLs