Genetic analysis of storage root formation in sugar beet
Roots are indispensable to plants by providing water, nutrient, anchorage, storage space and production of secondary metabolites(Saini et al. 2013). The plant kingdom shows a significant variation in root architectures resulting in different root types. Many crops like beets, carrots, radish, and turnips have storage roots as harvesting organs. An understanding of storage root formation is of greatest interest in terms of world’s food and feed supply in future.
Sugar beet is the most important sucrose-storing crop in the temperate regions. Despite decades of sugar beet research, the genetic control of sugar beet storage root development has not been analyzed in detail and no genes have been identified that may regulate storage root formation. Variation in root morphologies among Beta varieties and species can be exploited to study the genetics of taproot evolution and the effect of artificial selection due to breeding activities. Therefore, QTL studies in sugar beet could lead to the identification of genes that are controlling storage root formation. An identification of major regulators of storage root development could provide the opportunity to study homologous genes related to root thickening also in other crops.
This study is focused on understanding the genetics behind the sugar beet storage root formation. As long terms objective identified genes can be exploited in breeding to monitor the belowground root growth without destructing the plant growth. Moreover, the comparative studies of other storage root crops can be facilitated from the knowledge supply by this study.
A segregating sugar beet RIL5 population for storage root formation has been established from two independent crosses between two sugar beet parents and a leaf beet parent. The RIL5 population was phenotyped for storage root characters in two different years. For the construction of a genetic map, the genomes of the parents and F1 plants were resequenced. SNPs for KASP marker analyses have been identified by using different filtering methods after mapping the paired reads to the sugar beet reference genome. A genetic linkage map of the population was established. An initial QTL mapping revealed a major QTL for sugar beet storage root formation. Moreover, an additional phenotyping experiment is underway to validate the QTL.
This study presents the first QTLs identified for sugar beet storage formation. Therefore, the initial discoveries provide strategies to explore storage root development in sugar beet in more detail in the future. Fine mapping of the QTL region will be carried out to identify key regulators of taproot thickening. Therefore, the present study will provide a great advantage to breeders to make more efficient breeding programs to select the best breeding materials before harvesting.
Updated:09.09.2016 Responsible for this webpage: Dilan Sarange