THE PHENOTYPIC CHARACTERIZATION OF R(2) GENERATION TRANSGENIC RICE PLANTS UNDER FIELD CONDITIONS

The seed progeny produced by self-pollinating three R1 generation transgenic plants of Oryza sativa L. var. Taipei 309, which carried the neomycin phosphotransferase II (nptII) gene, were grown under field conditions at Maricopa Agricultural Experimental Station, Arizona, USA. The phenotypes of the R2 generation plants were compared with the phenotypes of non-transformed protoplast-derived plants of the same generation and non-transformed seed-derived plants. Transgenic plants were generally smaller with shorter flag leaves, took longer to flower and had reduced fertility. They developed fewer, shorter panicles, with relatively few spikelets which developed into mature seeds. The seeds from the transgenic plants were longer, but narrower than those produced by non-transformed plants. Significant phenotypic differences were observed between individuals within the group of R2 transgenic plants. The nptII gene was present in all transgenic plants, but the NPT II enzyme was not detected.