**3. Results and discussions**

## **3.1 Fresh weight**

From **Table 1**, the comparison with five types of chemical fertilizers (factor A), the concentration of chemical fertilizer (factor B), and the interaction between types and the concentration of chemical fertilizer (factor AxB) were highly significant. If compared with the fresh weight of strawberry plantlets, five types of chemical fertilizers as 21-21-21 (N-P2O5-K2O), 36-5-5 (N-P2O5-K2O), 30-20-10 (N-P2O5-K2O), 15-30-15(N-P2O5-K2O) and 10-52-17 (N-P2O5-K2O) showed an average amount of


*Different alphabets in the same column and row are significantly different at level 0.05 compared to LSD. \*\*Significant difference at the level of 0.01.*

#### **Table 1.**

*The effect of different chemical fertilizer types and concentrations on the fresh weight of strawberry plantlets after cultured for 4 weeks.*


*Different alphabets in the same column and row are significantly different at level 0.05 compared to LSD. \*\*Significant difference at the level of 0.01.*

#### **Table 2.**

*The effect of chemical fertilizer types and concentrations on the number of strawberry plantlets after 4 weeks of culture.*

fresh weight of 1.28–1.35 gL−1. According to the experiment, MS medium was the best medium to induce the fresh weight of plantlets (1.72 gL−1) because it contained macronutrients, micronutrients, and many kinds of vitamins [9, 11].

### **3.2 Number of plantlets**

In **Table 2**, to compare five types of chemical fertilizers (factor A), the concentration of chemical fertilizer (factor B) and interaction between types and concentration of chemical fertilizer (AxB) were all highly significant at level 0.01. MS medium, 21-21- 21 (N-P2O5-K2O), and 15-30-15 (N-P2O5-K2O) chemical fertilizers showed a similar number of plantlets (3.44, 3.87, and 3.48 plantlets/explant, respectively). At the concentration of chemical fertilizer, 0.5 g L−1 was the best concentration to induce plantlets of strawberries. The medium containing 0.5 g L−1 of 21-21-21 (N-P2O5-K2O) chemical fertilizer was the best medium to produce plantlets of strawberries (**Figure 2**) [11].

#### **3.3 Number of roots**

To study the effects of five types of chemical fertilizer, the concentration of chemical fertilizer and the interaction between type of chemical fertilizer and concentration of chemical fertilizer on root induction of strawberries were shown in **Table 3**. The type of chemical fertilizer (factor A) was significantly different at level 0.01. The concentration of chemical fertilizer (factor B) was shown to be significantly different at level 0.05. Also, the interaction between factors A and B was significantly different at level 0.05 too. Similar to [8], MS medium is shown to be the best medium to induce root growth in strawberries (5.09 root/explant). On the media, 21-21-21 (N-P2O5-K2O) and 15-30-15 (N-P2O5-K2O) were also good media to induce strawberry root (3.97 and 3.64 root/explant, respectively).

#### **Figure 2.**

*Plantlet was cultured on medium containing 0.5 g L−1 of 21-21-21 (N-P2O5-K2O) chemical fertilizer.*


*Different alphabets in the same column and row are significantly different at level 0.05 compared to LSD. \* Significantly different at level 0.05. \*\*Significantly different at level 0.01.*

#### **Table 3.**

*The effect of chemical fertilizer types and concentrations on a number of roots of strawberry plantlet after being cultured for 4 weeks.*

### **3.4 Root length**

Five types of chemical fertilizer (factor A), the concentration of chemical fertilizer (factor B), and interactions between types of chemical fertilizer and concentration of chemical fertilizer (A × B) on the root length of strawberries were investigated (**Table 4**). Factor A, factor B, and factor A × B were shown to be significantly different at level 0.01. The MS medium and the 21-21-21 (N-P2O5-K2O) chemical fertilizer medium were the best media to induce root length (2.42 and 2.21 cm/explant, respectively). Because higher fertilizer concentrations caused the plant to be unable


*Different alphabets in the same column and row are significantly different at level 0.05 compared to LSD. \*\*Significant difference at the level of 0.01.*

#### **Table 4.**

*The effect of chemical fertilizer types and concentrations on the root length of strawberry plantlets after being cultured for 4 weeks.*

to properly absorb nutrients for growth, the optimal concentration to promote root length (2.39 cm/explant) was 0.5 g L−1 [12].
