GENETICALLY MARKED MALE STERILE GENES AND YBRID SEED PRODUCTION

ADVANCED GENETIC SCIENCES, INC. 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 ALLELE. 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 ROGUEING OUT THE MALE FERTILE SEGREGANTS. THEIR 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, THEY WILL SELECT (BY TEST-CROSSING) A LINKAGE SUFFICIENT FOR HYBRID SEED PRODUCTION. THE MOST SUITABLE MARKER IS SEED COLOR, BECAUSE COLORED SEEDS CAN BE SORTED ELECTRONICALLY BEFORE PLANTING. TO THIS END, A BACTERIAL GENE WILL BE ENGINEERED 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.