EVALUATION OF SUGAR BEET BREEDING POPULATIONS BASED MORPHO-PHYSIOLOGICAL CHARACTERS UNDER SALINITY STRESS

Soil salinity is an important factor limiting crop productivity, especially in arid and semi-arid countries like Iran. Therefore, improving salt-tolerant varieties of crops such as sugar beet that could grow and produce acceptable yield in this stress condition is one of the most important objectives of plant breeding in Sugar Beet Seed Instutue (SBSI) of Iran. The main objective of this study was to evaluate the different sugar beet genotypes in terms of salinity tolerance based on physiological and morphological traits in greenhouse conditions and comparing its results with field experiments. In this study, quantity and quality characters of 12 sugar beet (Beta vulgaris L.) advanced breeding populations were investigated under stress(EC = 16 ds/m) and non-stress conditions in a factorial experiment in the greenhouse and split plot experiment in the field at the experimental station of Sugar Beet Seed Institute (SBSI) in Mian-Doab, Iran. Several characteristics such as, root yield (RY), white sugar yield (WSY), sugar content (SC), leaf length (LL), leaf width (LW), petiole length (PL), root impurities (Na, K and N), relative water content (RWC), relative water loss (RWL), and proline content were determined. The analysis of variation showed significant differences among the breeding populations for most traits such as root and shoot fresh and dry weights, sugar yield, impurities, petiole length and proline. In general, salinity stress conditions increased proline, specific leaf weight, leaf sodium, root length and total dry weight in comparison with non-stress condition but other traits decreased in salinity stress condition in greenhouse. In meanwhile, salinity stress conditions increased sugar content and decreased other traits in the field as compared with the non-stress condition. Genotypes SC C2*S7, SC C2*S10 and SC C2*S11 were found to be superior to the other genotypes for root and white sugar yields and sugar content. Genotypes SC 261*S7 and 191 were had the least root yield in the stress condition.