紧凑型玉米自交系D34是以丹340自交系的变异株选育而成的旅系。与P群杂交，所配组合大多属晚熟稀植大穗型品种；与Reid、Lan.杂交，所配组合大多属晚熟、中晚熟杂交种。D34自交系用途多样、配合力高、适应性广，是广为应用的优良自交系之一。

Compact corn D34 is the type of inbred lines on the mutant Dan 340 inbred line breeding and into the brigade of red bone. The varieties of D34 crossing with P group mostly are type of late-maturing, sparse and big ear, and that with Lancaster or Reid, mostly are the type of late maturing and mid-late maturing. So, D34 is one of the widely used excellent inbred lines with diversity, high combining ability and extensive adaptability.