GENETIC-VARIABILITY IN SYMBIOTIC NITROGEN-FIXATION BETWEEN PROVENANCES OF ACACIA-NILOTICA (L) WILLD EX DEL

Differences in nitrogen fixing abilities of 18 provenances (16 from India, 2 from Israel) of Acacia nilotica (L.) Willd. ex Del. were assessed in sterilized sand in chillum jars and unsterilized field soil in earthen pots, at Hisar (29 degrees 10'N lat., 75 degrees 46'E long., 215 m alt.), India. There were significant differences in growth and amount of nitrogen fixed and stored in plants (P < 0.01) between provenances. The values ranged from 10 to 34 mg N/plant in sterilized sand, and 11 to 44 mg N/plant in unsterilized soil. Maximum nodulation and nitrogen fixation occurred in Sirsa provenance followed by Pall, Coimbatore and Chandigarh provenances. Medinipur, Hisar (local provenance) and two exotics fixed significantly (P < 0.01) lower amounts of nitrogen. These differences attributed to genetic variability among provenances of Acacia nilotica. There were strong and positive correlations between number and mass of nodules with total nitrogen fixed in the plants. The results are important from the point of view of exploiting the genetical variability in A. nilotica in amelioration of wastelands.