Presenter: Dobech Enquayehush Mulu and Oscar B. Zamora Institution: University of the Philippines, Los Baños Subject Country: Philippines

2. THE EFFECT OF SEEDLING AGE, SPACING, AND SEASON ON PHYLLOCHRON, YIELD, AND YIELD COMPONENTS OF RICE, USING THE PRINCIPLES OF THE SYSTEM OF RICE INTENSIFICATION (SRI) Dobech Enquayehush Mulu, MSc University of the Philippines, Los Baños Major Adviser: Oscar B. Zamora, PhD Professor, UPLB

15. Figure 1. Tillering dynamics of rice shoot based on Katayama`s rice growth rule. Source: Vallois, 1997.

24. Table 1. Phyllochron length as affected by seedling age in the dry and wet seasons 2003 Phyllochron Length (days/leaf) Seedling Age Dry Season Wet Season 8 5.3 c 4.7 b 15 4.9 d 4.5 c 20 6.0 b 5.6 a 25 6.5 a 6.2 a CV 4.9 % 4.8%

25. Table 2. Phyllochron length as affected by variety in the dry and wet seasons 2003 Phyllochron Length (days/leaf) Variety Dry Season Wet Season Elon-Elon 5.7 a 5.5 a PSBRc-82 5.1 b 5.1 b CV 4.9% 4.8%

27. Table 3. Number of leaves on main stem (after transplanting) of rice as affected by the interaction of seedling age and variety in the dry season 2003 Number of Leaves on the Main Stem Variety Seedling Age (days) 8 15 20 25 Elon–Elon 13.0 a 13.0 a 10.0 c 9.0 d PSBRc-82 12.0 b 12.0 b 10.0 c 9.0 d

28. Table 4. Number of leaves on the main stem (after transplanting) of rice as affected by the interaction of seedling age and variety in the wet season 2003 Number of Leaves on the Main Stem Variety Seedling Age (days) 8 15 20 25 Elon–Elon 15 a 15 a 12 c 11 d PSBRc-82 14 b 14 b 12 c 11 d

29. Table 5. Number of productive tillers per hill of rice as affected by the interaction of seedling age and variety in the dry season 2003 Number of Productive Tillers per Hill Variety Seedling Age (days) 8 15 20 25 Elon–Elon 30.5 a 30.1 a 29.6 a 16.6 c PSBRc-82 22.0 b 22.2 b 21.6 b 18.2 c

30. Table 6. Number of productive tillers per hill of rice as affected by the interaction of seedling age and variety in the wet season 2003 Number of Productive Tillers per Hill Variety Seedling Age (days) 8 15 20 25 Elon–Elon 68.0 a 68.6 a 40.4 bc 38.0 d PSBRc-82 53.6 b 49.7 bc 42.4 cd 35.6 d

32. Table 8. Number of productive tillers per hill of rice as affected by season, 2003 Season Number of Productive Tillers per Hill Dry Season 23.84 b Wet Season 50.68 a CV 11.4%

34. Table 9. Number of filled spikelets per panicle of rice as affected by interaction of seedling age and variety in the dry season 2003 Number of Filled Spikelets per Panicle Variety Seedling Age (days) 8 15 20 25 Elon–Elon 265.7 a 234.9 b 233.5 b 212.9 c PSBRc-82 98.80 d 112.8 d 99.9 d 94.3 ed

37. Table 11. Grain weight per panicle of rice as affected by seedling age in the dry and wet seasons 2003 Grain Weight per Panicle (gm) Seedling Age Dry Season Wet Season 8 4.0 a 4.1 a 15 3.7 b 4.2 a 20 3.7 b 3.5 b 25 3.4 b 3.1 c CV 6.3% 9.0%

38. Table 12. Grain weight (t ha- 1 ) of rice as affected by seedling age in the dry and wet seasons 2003 Grain Weight (t ha -1 ) Seedling Age Dry Season Wet Season 8 3.9 a 7.8 a 15 3.83 a 8.1 a 20 3.6 a 6.1 b 25 2.5 b 5.9 b CV 14.9% 3.6%

41. Experiment 2 The Effect of Planting Distance on Phyllochron Length, Yield, and Components of Yield Using the Principles of the System of Rice Intensification Objective To determine the best plant spacing in terms of phyllochron length, yield, and yield components of two rice varieties in two cropping seasons.

44. Table 13. Phyllochron length of rice as affected by spacing in the dry and wet seasons 2003 Phyllochron Length (days/leaf) Spacing Dry Season Wet Season 20 x 20 cm 6.1 a 5.6 a 30 x 30 cm 5.5 b 4.9 b 45 x 45 cm 5.4 b 4.8 b CV 1.5% 2.1%

46. Table 14. Number of productive tillers per hill of rice as affected by interaction of spacing and variety in the dry season 2003 Number of Productive Tillers per Hill Variety Spacing (cm) 20 x 20 30 x 30 45 x 45 Elon–Elon 16.2 c 28.6 a 29.7 a PSBRc-82 16.0 c 21.8 b 23.3 b

47. Table 15. Number of productive tillers per hill of rice as affected by interaction of spacing and variety in the wet season 2003 Number of Productive Tillers per Hill Variety Spacing (cm) 20 x 20 30 x 30 45 x 45 Elon–Elon 20.4 d 37.9 c 63.9 a PSBRc-82 25.1 d 37.7 c 54.8 b

48. Table 16. Number of filled spikelets per panicle of rice as affected by spacing in the dry and wet seasons 2003 Number of Filled Spikelets per Panicle Spacing Dry Season Wet Season 20 x 20 cm 146.6 b 178.7 b 30 x 30 cm 174.5 a 217.0 45 x 45 cm 176.7 a 234.1 a

49. Table 17. Grain weight per panicle of rice as affected by spacing in the dry and wet seasons 2003 Weight of Grain per Panicle (gm) Spacing Dry Season Wet Season 20 x 20 cm 3.0 b 3.6 b 30 x 30 cm 3.4 a 4.6 a 45 x 45 cm 3.6 a 4.8 a CV 4.1% 9.9%

50. Table 18. Grain yield (t ha -1 ) of rice as affected by spacing in the dry and wet seasons 2003. Grain Weight (t ha -1 ) Spacing Dry Season Wet Season 20 x 20 cm 2.8 b 4.5 c 30 x 30 cm 3.9 a 6.1 b 45 x 45 cm 4.4 a 7.3 a CV 14.5% 5.6%

51. Yield difference due to spacing was mainly attributed to the number of productive tillers per hill, number of filled spikelets per panicle, and grain weight per panicle. The regression model for the dry season was: Yield = 1.014776 + 0.13 (number of productive tillers/hill) + 0.06 (filled spikelets/panicle) + 0.45 (grain weight/panicle).

53. The full set of SRI practices: transplanting younger seedling singly per hill at 45 x 45 cm spacing under minimum water management during the vegetative growth stage, mechanical weeding with rotary-hoe and using compost increased rice yield to 7–8 t ha -1 in the wet season, when relatively optimum growing conditions were prevailed. In the same season, older seedlings with similar management practices produced only 5-6 t ha -1 . This result suggests that the synergetic effect of all combinations of SRI practices used together.

54. Table 1. Phyllochron (day/leaf) of each leaf of rice as affected by variety and seedling age in the dry season 2003 Seedling Age (Days) Leaf Number on the Main Stem 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Total Leaves Elon-Elon 8 - - 4 3 3 3 3 3 4 6 7 8 9 9 7 13 15 - - 3 3 3 3 3 3 4 5 7 8 9 8 7 13 20 - - - 7 6 4 4 5 7 8 9 9 8 - - 10 25 - - - - 8 6 4 4 6 8 8 9 7 - - 9 PSBRc-82 8 - - 3 3 3 3 3 3 4 5 7 8 8 7 - 12 15 - - 3 3 3 3 3 3 4 6 7 7 7 7 - 12 20 - - - 7 4 3 3 4 4 5 7 7 7 - - 10 25 - - - - 8 6 4 3 4 7 8 8 7 - - 9

55. Table 2. The phyllochron (days/leaf) of each leaf of rice as affected by variety and seedling age in the wet season 2003 Seedling Age (Days) Leaf Numbers on the Main Stem 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Tot.Leaves Elon-Elon 8 - - 4 3 3 3 4 3 3 3 4 6 7 7 8 10 7 - 15 15 - - 4 3 3 3 4 3 3 3 4 5 6 7 8 10 7 - 15 20 - - - 6 4 4 4 4 5 6 7 7 8 10 7 - - - 12 25 - - - - 7 6 5 5 4 5 6 7 8 10 8 - - - 11 PSBRc-82 8 - - 3 3 3 3 3 3 3 3 4 6 6 7 7 8 - - 14 15 - - 3 3 3 3 3 3 3 3 4 5 6 7 6 7 - - 14 20 - - - 6 5 3 3 4 4 5 6 7 6 7 7 - - - 12 25 - - - - 6 5 4 4 4 5 5 6 6 8 7 - - - 11