Dynamic QTL Analysis on Rice Fat Content and Fat Index Using Recombinant Inbred Lines

Abstract

ABSTRACTFat content (FC) and fat index (FI) play an important role in determining quality of eating and nutrition for rice. The objective of this study was to determine genetic information during the grain‐filling period. Seventy‐one recombinant inbred lines (RILs) derived from a cross between japonica cultivar Asominori and indica cultivar IR24 were used to analyze the developmental behavior of FC and FI by conditional and unconditional quantitative trait loci (QTL) mapping methods. At four developmental stages of grain filling, 11 unconditional QTL and 10 conditional QTL for FC as well as 11 unconditional QTL and eight conditional QTL for FI were identified. In unconditional QTL analysis, qFC‐11‐2 and qFI‐3 were consistently detected at 21 and 28 days after flowering (DAF), whereas all the conditional QTL for FC and FI could be detected at only one stage. Nine conditional and nine unconditional QTL for FC and FI were detected in the earlier three stages while three and two unconditional QTL for FC and FI, respectively, were detected in the mature stage, which suggested that more QTL could be found in the early developmental stages. The qFC‐1‐2 and qFI‐1‐2, qFC‐2‐2 and qFI‐2, qFC‐4 and qFI‐4, and qFC‐9 and qFI‐9 were located on the vicinal marker intervals. The present study suggested that accumulation of fat was governed by time‐dependent gene expression. In addition, dynamic QTL mapping might be a valid way to reveal more genetic information about the fat accumulation.