OPTIMIZATION OF GERMINATION CONDITIONS OF Melia volkensii BY RESPONSE SURFACE METHODOLOGY

Germination of Melia volkensii was modelled using response surface methodology (rsm) whereby second order models were developed and the associated response surfaces analyzed. The factors under investigation were soil pH, temperature, chemical concentration and length of time of seed pre-treatment. Four chemicals were used for seed pre-treatment. These were potassium nitrate (KNO3), hydrogen peroxide (H2O2), gibberellic acid (GA(3)) and sulphuric acid (H2SO4). A four factor rotatable central composite design was used in the study. We established that in general, germination rates of Melia volkensii seeds are low. For the four chemicals used in the experiment, the germination rates were found to be 31.67% for KNO3, 39.08% for H2O2, 42.00% for GA(3) and 28.25% for H2SO4. The germination rate was optimized at 65.98% for KNO3 whereby the soil pH was 3.95, the temperature was 31.13 degrees C, the KNO3 concentration was 0.37% and the seed treatment time was 8.33 hours. For H2O2, germination rate was optimized at 65.24% whereby the soil pH was 4.83, the temperature was 30.43 degrees C, the H2O2 concentration was 2.92% and the seed treatment time was 8.76 hours. The germination rate was optimized at 76.49% for GA(3) whereby the soil pH was 5.52, the temperature was 26.77 degrees C, the GA(3) concentration was 0.03% and the seed treatment time was 7.65 hours. For H2SO4, germination rate was optimized at 57.26% whereby the soil pH was 4.70, the temperature was 27.21 degrees C, the H2SO4 concentration was 38.13% and the seed treatment time was 5.43 hours.