NSF Award
8722713
Dr. Jorgensen is developing a general method for producing hybrid seed which removes the primary barrier to the use of nuclear male sterile genes. These genes give rise to male sterility only when the plant is homozygous for the recessive male sterility alleles. As a result, male sterile plants must be propagated by backcrossing to male fertiles, yielding a mixed population of fertiles and steriles. Thus, pure stands of male sterile plants cannot be obtained without precise and expensive procedures for sorting out the male fertile segregants. Dr. Jorgensen's solution to this problem is to create linkage between a male sterile gene and a marker gene by introducing the marker gene to plant chromosomes by genetic transformation. From among many plants independently transformed with a suitable marker gene, he will select (by test-crossing) a linkage sufficient for hybrid seed production. The most suitable marker is seed color, because colored seed can be sorted electronically before planting. To this end, he is engineering a bacterial gene that determines indigo synthesis so that it can be expressed in plant cells. The method offers clear advantages over currently available technologies, whose limitations result in high costs and/or low purity of hybrid seed in many crop plants. %%% The use of hybrid plants is well known as a means to enhance plant productivity and value. This value results not only from the increased vigor and yield of hybrids, but also from their improved uniformity and quality. Because most important crop plants display substantial heterotic vigor, hybrid seed is widely perceived to be a valuable commodity. This project is designed to allow these hybrids to be sorted out as seeds in an economically feasible way. The aim is to introduce, via genetic engineering, a set of genes that produce a colored compound in male sterile plants. The use of male sterile plants is important in producing hybrid plants because they cannot self pollinate.
