# Alleploatible Potential of Sunflower Genotypes at Different Growth Stages on Lettuce
## 3 Results  
Results of the ANOVA showed that sunflower water extracts had different effects on the germination and growth of lettuce seedlings (Table 2). The concentration of water extracts significantly affected all measured parameters, while only the growth stage had no significant effect on seedlings' root length. Particular main factors and their interactions influenced seedlings' shoot length and fresh weight. \begin{table}
\begin{tabular}{c c c c c c} \hline
**Source of Variation** & **Degree of Freedom** & **Germination** & **Root Length** & **Shoot Length** & **Fresh Weight** \\ \hline Growth stage (S) & 1 & 7 & 0.05 & 0.64 * & 1.03 \\ Concentration (C) & 2 & 667 * & 83.22 * & 23.76 * & 791.24 * \\ Genotype (G) & 8 & 27 & 0.24 * & 0.14 & 9.10 * \\ S \(\times\) C & 2 & 57* & 0.21 * & 0.17 & 1.26 \\ S \(\times\) G & 8 & 26 & 0.42 * & 0.21* & 3.08 * \\ C \(\times\) G & 16 & 11 & 0.16 * & 0.11 & 4.02 * \\ S \(\times\)C \(\times\) G & 16 & 23 & 0.20 * & 0.07 & 2.13 \\ \hline \end{tabular}
* Significance at \(p<0.05\).  
\end{table} 
Table 2: Analysis of variance (mean squares) for traits in tested growth stages (butonisation and flowering), treatments (control, 1 and 2.5% water extract concentrations) and sunflower genotypes. Gerimation of lettuce was significantly affected by the \"growth stage \(\times\) concentration\" interaction (Table 2, Figure 1). For both growth stages, 2.5% concentration showed significantly higher allelopathic potential, with average germination reduction of 6.3% compared to control. The greatest negative effect was recorded in the butonisation stage with 2.5% concentration. A significant decrease in lettuce seedlings' root length was recorded in all treatments with sunflower water extracts (Figure 2a,b). The lowest inhibition was with Genotype 2 (11.3%) and the highest with Genotypes 3, 4, 5 and 7 (74.1-80.6%) for a lower concentration of extracts from leaves collected in the butonisation stage. An increase in concentration resulted in a root length decrease of over 80% in all treatments, except Genotypes 1 and 2. Similarly, with lower concentrations of extracts from the flowering stage, root length was markedly inhibited in the majority of treatments for over 70%. Only Genotype 3 had slightly lower allelopathic potential with a root length reduction of 56.1%. Extracts in higher concentrations obtained in the flowering stage induced substantial inhibition, which was highest with Genotypes 1, 2, 4, 5, 6 and 7, and ranged from 80.1% to 84.7%. The allelopathic effect of sunflower extracts on the shoot length of lettuce seedlings is presented in Figure 2c with significant interaction for \"growth stage \(\times\) genotype\". Significantly higher reduction of lettuce shoot length was observed in treatments with Genotypes 1, 2 and 9 from the flowering stage compared to the butonisation stage. For the butonisation stage, the greatest inhibition was recorded with Genotypes 5 and 8. The fresh weight of lettuce seedlings was significantly affected by the \"concentration \(\times\) genotype\" and \"growth stage \(\times\) genotype\" interactions (Table 2, Figure 3a,b). Regarding the former (Figure 3a), for all the sunflower genotypes, 2.5% concentration showed significantly higher inhibitory potential compared to 1% concentration and control. Genotypes 4, 5 and 7 at 2.5% concentration showed the highest allelopathic potential and reduced the fresh weight of seedlings for 51.9%, 56.5% and 54.2%. A positive effect was recorded with Genotypes 1 and 9 at lower concentration. For the \"growth stage \(\times\) genotype\" interaction (Figure 3b), results revealed a significantly greater reduction of fresh weight with Genotype 9 from the flowering stage compared to the butonisation stage. The greatest inhibition for the butonisation stage was recorded with Genotypes 5 and 7, and with Genotypes 4 and 5 for the flowering stage. Figure 1: Allelopathic effect of water extracts from sunflower leaves collected in the butonisation and flowering stage on the germination of lettuce.