Optimizing plant spacing and seedling age for enhanced growth and yield of transplanted sorghum (Sorghum bicolor) under aberrant weather conditions

Transplanting sorghum seedlings into agricultural fields at the commencement of the rainy season can significantly enhance stand uniformity, mitigate replanting expenditures and reduce the duration of the crop’s presence in the field, thereby facilitating earlier harvests and bolstering food security. Moreover, these seedlings were cultivated within controlled environments in nurseries, utilizing minimal water resources. This study evaluated the effects of seedling age and plant spacing on survival, yield and shoot fly incidence in transplanted sorghum to support evidence-based cultivation practices. A field experiment was conducted in the Agricultural Research Station, Kovilpatti, Tamil Nadu using a split-plot design with three replicates. Main plots compared three spacing (45 × 15 cm, 45 × 30 cm, 45 × 45 cm) and subplots evaluated seedling age at transplanting (15, 18 and 21-days transplants) versus direct sowing (control). Direct-sown seeds had the highest survival (96 %), followed by 18-day transplants (78 %). Shoot fly incidence didn't differ significantly across treatments. The combination of 18-day seedlings at 45 × 15 cm spacing yielded the highest grain production (3506 kg ha-1), revenue (₹87211) and benefit-cost ratio (2.88). Direct sowing at the same spacing produced the highest stover yield (11900 kg ha-1). Transplanting 18-day transplants at 45 × 15 cm spacing optimizes grain yield and profitability without increasing pest incidence. This approach offers a viable alternative to direct sowing, particularly in environments where earlier harvests are critical. The Pearson correlation analysis identified strong positive associations among grain yield, seed weight and plant height.