Response of early maturity soybean cultivars to row spacing in full-season crop and double-crop systems

Abstract

Cultivar selection and crop systems are important factors for maximising soybean seed yield. The effect of row spacing (RS1 = 75 cm, RS2 = 25 cm) on the performance of 10 early maturity soybean cultivars grown in full-season and double-crop system for two consecutive years was studied. The agronomic traits measured were seed yield (SY), plant height (PH), pods per plant (PP), first pod height (FPH), crude protein. RS had a significant effect on SY, PH, PP and FPH. Higher SY (P < 0.01) was recorded in RS2 regardless of the crop system. The double-crop system yield reduction index of the tested cultivars ranged from 30.0% to 56.4% and from 21.5% to 57.2% for RS1 and RS2, respectively. Cultivars differed (P < 0.01) for all traits in both RS and crop systems. Maturity Group I cultivars showed the highest productivity; the cultivars PR92B63 and Atlantic were better adapted to the full-season crop system (SY > 5.67 t/ha); cv. Sphera was the most productive in the double-crop system (4.66 t/ha); cv. PR92M22 showed good adaptability to both cropping systems. In conclusion, the significant effect of RS and crop system on SY was observed, whereas different high yielding cultivars were identified as suitable for full-season and double-crop system.