Detection and analysis of QTL for panicle length in rice using a high-density genetic map

Objective  To deeply explore new genes related to panicle length and provide a basis for the study of genetic mechanism of panicle length regulation and molecular breeding in rice.

Method Two superior parents, ‘ZP37’ and ‘R8605’, as well as 208 recombinant inbred lines (RILs) derived from the cross of ZP37/R8605 were used as a mapping population to locate quantitative trait loci (QTLs) for panicle length in three different environments through the high-density linkage map of whole genome resequencing, and to analyze their pyramiding effects.

Result A total of 11 QTLs for panicle length were detected on chromosomes 3, 4, 7, 8, 9 and 12, with the logs of odds (LODs) ranging from 3.07 to 12.87 and contribution rates ranging from 2.17% to 10.94%, seven of the QTLs were new loci, and the remaining four QTLs overlapped or were close to the reported panicle length genes and QTLs. Among them, four stable QTLs were detected repeatedly in two different environments, and by analyzing the lines that pyramiding different numbers of panicle length QTLs, the results showed that the panicle length QTLs showed an additive effect, and the increase in the number of QTLs significantly increased the panicle length of rice.

Conclusion The results of this study provide a solid foundation for cloning and functional analysis of rice panicle length QTLs, as well as a theoretical basis and genetic resources for high-yield rice breeding.