Growth and ions (Na/sup +/, K/sup +/ and Cl/sup-1/-) accumulating pattern of some brassica genotypes under saline - sodic field condition

The growth and ionic uptake pattern of some Brassica genotypes i.e., Rainbow, Wester, Durr-e-NIFA, Abaseen 95 (Brassica napus) and NIFA raya (Brassica juncea) under saline-sodic field conditions was studied. Two sets of experiments on normal and saline-sodic site were conducted at NIA experimental farm, Tandojam, Pakistan during Rabi 2006-07. The salinity of the experimental site ranged between 11.0-22.9 dS/m and the pH was alkaline (8-8.6). The dominant cation was sodium (Na). The growth performance was recorded at the time of crop harvest in terms of plant height, grain weight / plant, grain yield and 100 grain weight. It was observed that the performance of Wester was better followed by NIFA- raya. The ionic uptake pattern, of leaves, stem and roots showed that the accumulation of Na was less in leaf as compared to stem and roots. However, the genotypes having better performance we re found to have accumulating type of behavior showing comparatively higher Na contents in all plant parts than other genotypes. This suggests that these genotypes might adjust their osmotic potential through the accumulation of sodium in vacuole. On the other hand trend in case of K accumulation was reverse i.e. high in leaves and stem as compared to roots. Higher accumulating pattern of K in leaves might be helpful for reducing the toxic effects of sodium. However, no correlation was observed between K-Na selectivity or K/Na ratio among the genotypes tested. It is therefore concluded that better selective mechanism for Na uptake and strict control of intercellular Na influx for cellular osmotic adjustment could be selected for saline environment. (author)