STABLE CARBON ISOTOPE AND RESTRICTION FRAGMENT LENGTH POLY MORPHISM TECHNOLOGIES FOR IMPROVEMENT OF WATER-USE EFFICIEN-CY OF C3 PLANTS

THE LACK OF EFFICIENT TOOLS TO IDENTIFY GENOTYPES OF SUPERIOR WATER-USE EFFICIENCY (WUE) HAS LED TO LITTLE PRACTICAL SUCCESS IN IMPROVING CROPS WITH REGARD TO THIS VERY IMPORTANT TRAIT. HOWEVER, STABLE CARBON ISOTOPE ( (13)C) ANALYSIS IS PRESENTLY EMERGING AS A POTENTIALLY HIGHLY EFFICIENT MEANS OF EVALUATING PLANTS FOR WUE, ALTHOUGH THE TECHNOLOGY HAS NOT YET BEEN APPLIED TO CROP DEVELOPMENT. IN A PRELIMINARY STUDY IT WAS FOUND THAT A WILD TOMATO SPECIES (L. PENNELLII) WAS OF MUCH GREATER WUETHAN WAS THE DOMESTIC TOMATO (L. ESCULENTUM) AND THAT THE INTERSPECIFIC F(1) HYBRID INHERITED THE WUE OF THE WILD PARENT. WUE WAS FURTHER FOUND TO BE STRONGLY POSITIVELY CORRELATED WITH (13)C. IN A SECOND SMALL STUDY IT WAS FOUND THAT THE PREDICTIONS OF (13)C BASED ON RESTRICTION FRAGMENT LENGTH POLYMORPHISMS (RFLPS) VERY ACCURATELY REFLECTED OBSERVED (13)C VALUES, AND THAT AS FEW AS THREE RFLP LOCI CONTRIBUTED OVER 70% OF THE VARIANCE FOR (13)C. IN THIS PHASE I PROJECT, THE CORRELATION BETWEEN WUE, (13)C, AND RFLPS IN TOMATO WILL BE CONFIRMED IN A BIGGER, GREATLY VARIABLE POPULATION (F(2)). IF THIS CORRELATION CAN BE DEMONSTRATED,IT OFFERS THE ADVANTAGES OF (1) EVALUATION AND COMPARISON OFPLANTS GROWN IN ANY ENVIRONMENT, (2) SIMULTANEOUS SELECTION FOR MULTIPLE TRAITS-ONE OF THEM BEING WUE VIA RFLP SELECTIONINDICES, AND (3) THE OPPORTUNITY TO IDENTIFY THE ACTUAL GENES TARGETED BY THE RFLPS, CLONING OF THESE GENES, AND THEIR USE IN CROP IMPROVEMENT THROUGH TRANSFORMATION OF HIGHER PLANTS. THE TECHNICAL APPROACH IS SUITABLE FOR ALL C(3) PLANTS PROVIDED THAT SUFFICIENT GENETIC VARIABILITY ANDRFLPS EXIST.