Chiang Mai Journal of Science

Gibberillins (GAs) are essential plant hormones that play a major role in height or stem elongation regulation. Several genes for both GA biosynthetic enzymes and GA signal transduction pathways were revealed to be involved in stem elongation in several plant species, including economic crops such as rice, maize and wheat. In oil palm (Elaeis guineensis Jacq.), height is an important trait, as it is difficult to harvest from excessively tall plants. If we can determine what the genetic controls for height are, then genes can be used to develop markers for marker-assisted selection (MAS). These markers would be beneficial for oil palm breeders to select elite oil palm varieties with dwarf loci. Reports of height-controlling genes in oil palm are limited. During our previous work, we identified EgDELLA1 at chromosome 14, as being associated with height in the Golden Tenera (GT) population. In this study, we aim to identify additional genes controlling height, targeting three candidate genes, including growth regulating factor 1 (GRF1), GA20-oxidase (GA20-ox) and dwarf8. Here, we show that growth regulating factor (EgGRF1), at chromosome 10, is highly associated with height in the GT population for all four times of height phenotype recorded, at p values 0.0276, 0.0275, 0.0487 and 0.0253 for height (HT)-1, HT-2, HT-3 and HT-4, respectively. In addition, EgDELLA1 was more associated with HT-4, with a p value of 0.0103. We also provide the marker information for EgGRF1 which will be used for oil palm variety improvement, using MAS, in the near future.