Impact of epistasis and QTLxenvironment interaction on the developmental behavior of plant height in rice (Oryza sativa L.)

QTLs with epistatic effects and environmental interaction effects for the d evelopmental behavior of plant height in rice were studied by conventional and conditional methods for quantitative trait loci (QTLs) by mapping with a doubled-haploid population of 123 lines from IR64/Azucena in three enviro nments. The results showed that epistatic effects were important and most e pistasis could be detected only by conditional QTL mapping, while most non- epistatic QTLs could be detected by both conventional and conditional metho ds. Many modificative QTLs showed only epistatic effects without their own additive effects at some stages. QTLxenvironment (QE) interaction effects w ere detected more often than QTL main effects for plant-height behavior, wh ich might indicate that gene expression could be greatly affected by the en vironment. No QTLs had effects during the whole of ontogeny. Conditional QT L mapping might be a valid way to reveal dynamic gene expression for the de velopment of quantitative traits, especially for epistatic effects.