PRINCIPAL COMPONENT ANALYSIS AND ASSESSMENT OF BRASSICA NAPUS L. ACCESSIONS FOR SALT TOLERANCE USING STRESS TOLERANCE INDICES

Due to genetic variations, the crop plants show different responses on exposure to salinity stress, enable plant biologists to find salinity tolerant types of crop plants. Many plant breeders have been successful in improving the salinity tolerance in various crops using plant vigor or seed yield as the main criteria for selection. Selection becomes more useful and feasible if the crop possesses distinguishing indicators of salt tolerance at the cellular, tissue or whole plant level. Soil salinity occurs in patches and is more heterogeneous in field conditions. Therefore screening plants in greenhouse conditions where saline conditions are reasonably uniform is effective and credible. Hydroponic culture technique is commonly used for studying the effects of salinity on crop plants as it helps in observing the effects of elemental deficiencies and toxicities. In the present study 60 accessions of Brassica napus were evaluated for salinity tolerance using hydroponic technique. Data were recorded on various seedling traits (root length, shoot length, fresh root weight, fresh shoot weight, dry root weight, dry shoot weight and Na+/K+ ratio) and salinity stress indices were calculated. Ten salt tolerant (G-96, ZNR-1, ZM-M-5, 23627, R-3, ZMR10, BLBN, RBJ-8007, ZMR-2, B-56 and six sensitive (Legend, Laclone, Faisal, Shiralee, Long and ZMR-5) accessions were selected on the basis of computed indices through principal component analysis (PCA). This study may be helpful for the comparison of salinity indices in a controlled experimental assay and for the identification of salinity tolerant brassica types to be used in further breeding programs.