TABLE 1.
Origins of soybean rhizobial isolates and agricultural-ecological-climatic characteristics of sampled regions
| Site | Designation of isolates | No. of fields sampled | No. of isolates | Previous cropa | Agricultural-ecological-climatic region (region and soil characteristics)b |
|---|---|---|---|---|---|
| Ujjain (Madhya Pradesh) | SR66-70 | 2 | 5 | Wheat | A (hot and semiarid, medium and deep black soils, coarse to fine loamy, highly alkaline, moderate to gentle slope) |
| Indore (Madhya Pradesh) | SR71-75 | 1 | 5 | Chickpea | A |
| Khandwa (Madhya Pradesh) | SR76-79 | 2 | 4 | Fallow | A |
| Raipur (Chattisgarh) | SR80-91 | 5 | 12 | Wheat | B (hot and subhumid, red and yellow soils, moderate clay to deep clayey, slightly acidic to slightly alkaline, moderate to gentle slope) |
| Jabalpur (Madhya Pradesh) | SR92-95 | 2 | 4 | Black gram | C (hot and subhumid, red and black soils, deep loamy, neutral to slightly acidic, moderate to gentle slope) |
| Sehore (Madhya Pradesh) | SR96-97 | 1 | 2 | Red gram | C |
| Chengalpattu (Tamil Nadu) | SR98-100 | 1 | 3 | Green gram-red gram intercropping | D (hot and subhumid to semiarid, coastal alluvium-derived soils, clayey, slightly alkaline to moderately alkaline, level to very gentle slope) |
| Gwalior (Madhya Pradesh) | SR101-108 | 3 | 8 | Wheat | E (hot and semiarid, alluvium-derived soils, loamy to clayey, slightly alkaline, gentle to very gentle slope) |
| Mirzapur (Uttar Pradesh) | SR109-115 | 4 | 7 | Wheat | E |
Crop grown in the previous season.
From the National Bureau of Soil Survey and Land Use Planning, India, and Indian Council of Agricultural Research, New Delhi, India. Hot and semiarid, mean annual rainfall of 500 to 1,100 mm, moisture index of −33.3 to −66.7, temperature of >22°C, and length of growing period (LGP) of 90 to 150 days; hot and subhumid, mean annual rainfall of 1,000 to 1,500 mm, moisture index of +20 to −33.3, temperature of 15 to 22°C, and LGP of 150 to 180 days; hot and subhumid to semiarid, mean annual rainfall of 900 to 1,600 mm, moisture index of −66.7 to 0, temperature of >15 to 22°C, and LGP of 90 to 210 days. Soil pH descriptions: neutral, 6.6 to 7.5; slightly acidic, 6.1 to 6.5; slightly alkaline, 8.0 to 8.5; moderately alkaline, 8.6 to 9.0; and highly alkaline, >9.0. Soil topology (slope) descriptions: level, <1 to 3%; very gentle, 1 to 3%; gentle, 3 to 8%; moderate, 8 to 15%.