Germination and Growth Performance of Rubber Seedlings (Hevea brasiliensis Muell) in Response to Growing Media and Different Rates of Gibberellic Acid (Ga3)

Abstract

A study investigated rubber seedling's germination and growth performance in response to growing media and gibberellic acid (GA3) rates. This study was laid out in 4 x 3 factorial arrangements in Completely Randomized Design (CRD) with four growing media as Factor A and three levels of GA3 as Factor B. All treatments were replicated three times. Results revealed that rubber seeds placed in garden soil + vermicast media mixture significantly exhibited the earliest seed germination of 10.78 days, significantly different from the rest of the treatments. This medium significantly gave the highest germination (84.44%), developed the tallest plants (59.94 cm) with the most number of leaves (12.86) and longest roots (8.32 cm). Seedlings from this media also developed the biggest stem diameter (2.80 mm) and 100 percent normal seedlings. However, seedlings were grown in garden soil mixed with rice hull statistically exhibited the most number of roots (10.89) per seedling. Application of GA3 at 100 ppm significantly enhanced the earliest seed germination of 12.25 days and highest germination (78.33%), produced the tallest plants (59.64 cm) gave the most number of leaves per plant (12.05). This treatment also exhibited the most number of roots (10.59) and stemmed diameter (1.69 cm) comparable to those treated with 50 ppm GA3. Likewise, the application of 100 ppm GA3 significantly gave the highest percentage of normal seedlings (93.75%).