TDK1-Sub1 is the product of the transfer of the SUB1 gene from IR40931-33-1-3-2 to TDK1 by using marker assistance in backcross breeding (IR40931-33-1-3-2/3*TDK1). TDK1-Sub1 is a glutinous, photoperiodism non-sentive variety, with growth duration 139-145 days. It has a semidwarf plant type (106–125 cm), wide adaptability, and is suitable for areas subject to flooding on the 7 main plains of the Central and Southern Agricultural  Regions of Lao PDR. However, the variety is susceptible to damage from brown plant hopper, green leaf hopper, neck blast disease and Fe toxicity. The rice paddy is straw colored, while the grains are small but long (this contrasts with the brown paddy color of TDK1, which also has large, long grains).. TDK1-Sub1 grains have good milling qualties with a high milling percentage, when compared with TDK1 dry season irrigated rice. The cooked grain has good ealiting qualities and is soft but non-aromatic; when re-cooked it retains its softness and palatability.Field trails were conducted in flood prone areas of the Xebangfai plain in the wet seasons of 2009, 2010 and 2011, in four districts of Khammouane province and 1 district of Savannakhet province. When compared with TDK1 under flooded conditions, TDK1-Sub1 performed much better than TDK1, having a much higher plant survival under and giving a grain yield similar to that for areas not subject to flooding. In the 2011 wet season, when typhoons caused large areas of the Xebangfai Plain to be flooded, the 20 on-farm experimental sites were flooded to depths of 1.1 to 2 meters for durations of between 12 and 18 days. TDK1 was badly damaged by the flooding, with no plants surviving (and no harvestable yield). In contrast, between 60-100% of plants of TDK1-Sub1 survived, giving final grain yields ranging from 1.2 to 3.7 tons/ha.

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