Variations in the morphology of rice plants regenerated from protoplasts using different culture procedures - Protoclonal variation of protoplast-derived rice plants

Rice protoplasts were cultured using 4 different culture procedures such as agarose embedding (AE) without feeder cells and the use of filter membrane s (MEM), one layer of nylon mesh (MS1), or a double layer of nylon mesh (MS 2) with the inclusion of Lolium multiflorum as feeder cells. The protoplast plating efficiency was highest on the MEM, followed by MS2, MS1 and AE. Ho wever, plant regeneration frequencies were highest for MS1, followed by MS2 , MEM and AE. The protoclonal plants differed in the morphology of leaves, flowers, spikelets, and panicles in comparison to seed-derived plants. They varied in almost every phenotypic characters evaluated. In many cases, the variation was significantly different in characteristics such as plant hei ght, flag leaf length and width and ratio, and in panicle characteristics s uch as panicle length, number of primary branches, and number of spikelets per panicle. The number of seeds per panicle was greatly reduced in protocl onal plants when compared with seed-derived control plants. The seeds showe d also significant differences in grain length and width in comparison to t he control plants. Among the 4 groups of protoclonal plants derived from th e 4 different culturing procedures themselves, there were also variations i n almost all the phenotypic characteristics assessed.