Healthier rice seedlings and less bakanae disease with paclobutrazol treatment

Bakanae disease symptoms can vary according to a number of circumstances, including age, cultivar resistance, and stress levels. Since younger plants are more vulnerable to infection and the effects of the fungus's gibberellin synthesis, symptoms are typically more noticeable in these plants. In general, severe bakanae symptoms are more likely to arise in stressed or weak plants. Poor seedling emergence, elongated rice seedlings, fewer and thinner tillers, yellowish green leaves, crown rot, stunting, empty panicles, discolored grains, and possible wilting that resulted in plant mortality were among symptoms of the disease.

Paclobutrazol (PBZ) had no significant effect on rice seed germination, regardless of Fusarium fujikuroi presence. While it reduced seedling height, PBZ at 25–100 mg/L improved root length when combined with the pathogen. Lower doses (3–6 mg/L) alleviated chlorophyll loss in infected seedlings. The highest proline levels and enhanced antioxidant enzyme activity were observed with 100 mg/L PBZ. The LC₅₀ was 0.874 mg/L, with low concentrations suppressing fungal growth and higher doses (50–100 mg/L) significantly lowering infection and disease severity. These results suggest PBZ is effective in managing bakanae disease and boosting rice resistance.

According to Mohammed Fathi El-Nady and Hossam S. El-Beltagi, the investigatosr who led the study, this study presents promising results for treating rice seeds before planting with relatively low concentrations of paclobutrazol to eliminate or at least reduce the incidence of bakanae disease in rice and improve seedling growth characteristics. This pre-planting treatment is also easier and more cost-effective in practical applications.