Genome Assembly and Annotation of Vietnamese Rice Lines with Diverse Life-Cycle Durations

Rice is not only the primary source of nourishment for billions but its production is also the livelihood for more than 150 million people.Vietnam ranks fifth in global rice production, with 43 million tons, accounting for 8.37% of world production. The Northern provinces of Vietnam are divided into three main regions: Red River Delta, Northern mountain areas, and the North of Central midlands. The first two regions face deep and unpredictably cold weather at the seedling stage, whereas the later region has frequent flash floods at harvesting time. Due to the impact of climate change, deep cold and flooding have occurred seriously in these regions in recent years, and it is warned to become more serious in the coming time. To escape from such harsh weather conditions, creating rapid-cycling varieties is vital to our mission at the Field Crops Research Institute (FCRI) in Viet Nam. Developing shorter life-cycling varieties allows for later planting in the spring, avoiding potential periods of cold, without intruding on the planting dates for the summer growing season. In addition, more rapid cycling varieties reduce the risk of flooding from typhoons that typically appear at the end of the summer season in the North of Central Midlands. We are collaborating with the University of York to develop the Vietnam rice GWAS platform for use in identifying QTL impacting life-cycle duration and develop genomics-guided molecular markers defined from the hundreds of rice genomes. These markers are to be used in breeding programs to produce more rapid-cycling varieties. Two F2 - segregating populations were generated from 4 parental lines: an Indica population (PD211/GL37) and a Japonica population (J23/SRA2-1). Each combination was generated from two parents which are far different in total growth duration.