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1. The seedling stage starts right after emergence and lasts until just before the first tiller appears. During this stage, seminal roots and up to five leaves develop.
2. As the seedling continues to grow after the first Prophyll leaf, two more leaves develop. Leaves continue to develop at the rate of 1 every 3-4 days during the early stage.
3. After the first leaf (Prophyll) developed, the second leaf with well developed leaf blade and attain full shape. Subsequent leaves also develop only after the complete development of the penultimate leaves. It takes 4-5 days before the panicle initiation of panicle primordial afterwards 7-8 days.
4. The development of one full leaf requires 100o degree days before the initiation of panicle primordia as about 170o degree days. Thus when the rice plant is grown at 20o C, leaves emerge every five days (100 degree days/20o C = 5 days). When it is grown at 25 o C, it develops every four days before panicle primordial initiation. (Yoshida 1981)
5. Secondary adventitious roots that form the permanent fibrous root system rapidly replace the temporary radicle and seminal roots.
6. This is an 18-day-old seedling ready for transplanting. The seedling has 5 leaves and a rapidly developing root system.