Seedling, early vegetative, and adult plant growth of oilseed rapes (Brassica napus L.) under saline stress

Salinity is a major limiting factor for early crop establishment and yield. In this study, 131 B. napus genotypes were evaluated for germination and early seedling growth in Murashige Skoog medium supplemented with NaCl. Eight genotypes were then evaluated for adult plant tolerance to salinity in a semi-hydroponic system using 1.4, 5, 10, 15, 20, and 28 dS m-1 salt stress. Relative salt tolerance (RST) was calculated and compared with genotype performance under no salt stress (control). The area under the germination progress curve (AUGPC) varied from 53-90 in the control and from 6-89 under 200 mM NaCl stress. The seedling vigor index (SVI) ranged from 200-1606 and 10-736 in the control and 200 mM salt stress, respectively. The RST for germination, root length, shoot length, and SVI ranged from 8-97.7%, 2-98.3%, 6.5-70.8%, and 1.9-83%, respectively. Root length was most severely affected by saline conditions, followed by shoot length and AUGPC when RST percentages of these traits were compared among responses of the 131 genotypes. Genotypes showed varied levels of proline and glucosinolate accumulation under different levels of saline stress. Greater accumulation of proline and glucosinolates was recorded with increased salinity level. This study indicates that variation exists in seedling and adult plant responses to saline stress in the B. napus genotypes and that improvement for salinity tolerance requires selection at the seedling, vegetative, and adult plant stages.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author