Growth and yield of soybean (Glycine max L.) varieties as influenced by different doses of Bradyrhizobium japonicum inoculate in dry land of the Arabia Sea coast area (Balochistan province, Pakistan)

Soybeans ( Glycine max L.) are an important source of oil and protein for a large part of the population of Asia and America. It is known that in soybean the formation of arbscular mycorrhiza and root nodules leads to an increase in fresh weight, dry weight and seed weight compared to the control. However, in Pakistan, and especially in the Balochistan province, the effect of treating soybean seeds with inocula is extremely poorly studied. We perforemed our study to check the adaptability of soybean varieties under rhizobia inoculation in the coastal region. The obtained data are novel for the dry tropical area of Balochistan near the Arabian Sea (20 km) Research was conducted at Agronomic research farm of Lasbela University of Agriculture, Water and Marine Sciences, Balochistan during winter season 2018. Randomized Complete Block design (RCBD) with factorial arrangement having net plot size 4.5 m×3 m (13.5 m2) was used with three replications. Treatments comprise two soybean varieties NARC I and NARC II and three doses of Bradyrhizobium japonicum inoculum, i.e. 200 g·acre-1, 400 g·acre-1 and 600 g·acre-1. The results showed that maximum plant height (35.4 cm), number of pods (24.7 plant-1), pod length (4.5 cm), the number of nodules (64.5 plant-1), root length (13.2 cm), seed index (31.8 g), oil content (34.5 %), protein (37.7 %), seed yield (1160.0 kg·ha-1) and biological yield (2019.7 kg·ha-1) was recorded in NARC II variety. The interaction NARC I×600 g·acre-1 inoculum indicated maximum plant height (41.3 cm), number of pods (31.3 plant-1), pod length (4.8 cm), number of nodules (83.6 plant-1), root length (15.3 cm), seed index (40.2 g), oil (38.0 %) and protein (43.0 %) content, seed yield (1333.8 kg·ha-1), biological yield (2325.0 kg·ha-1), and harvest index (1.3 %). Minimum plant height (22.6 cm), number of pods (15.0 plant-1), pod length (3.1 cm), number of nodules (42.3 plant-1), root length (7.5 cm), seed index (18.5 g), oil content (29.8 %), protein (30.5 %), seed yield (876.3 kg·ha-1), biological yield (1448.3 kg·ha-1) and harvest index (1.1 %) were found for NARC I×200 g·acre-1. Based on the results it was concluded that different doses of inoculum significantly affect the soybean varieties. Soybean variety NARC II produced maximum seed yield under 600 g·acre-1 inoculum doses. Maximum nodule formation was also found at an inoculum rate of 600 g·acre-1.