Effect of salinity stress on sugar beet seed germination indices in laboratory and greenhouse conditions

To identify a reliable procedure for studying effects of salinity on sugar beet seed germination under controlled and outdoor conditions as well as to find out the range of salinity concentrations for discriminatiation of genotypic differences for physiological characteristics, three separate experiments were conducted. In the first experiment four levels of salinity (Normal, EC=16, EC=20 and EC=24 dS.m-1) and 20 sugar beet genotypes were studied using factorial arrangement in completely randomized design with four replications. Seedling characteristics as; seed germination, abnormal seedlings, root and hypocotyls length were measured and recorded. The first experiment was a factorial experiment on the basis of a completely randomized design with four replications. The second experiment was carried out in two sizes of Perlits (small and large) as growing media in the greenhouse. It consisted of a tolerant and a susceptible lines that were identified at two EC=16 and EC=20 levels in the previous experiment. In the third experiment, seed germination of 19 sugar beet genotypes were assessed under normal and salt concentrations of EC=16 factorial arrangement in completely randomized design with three replications. Results showed that seed germination was similar in EC=16 and EC=20 dS.m-1 under laboratory conditions and 50% seedling losses was observed at EC=16 dS.m-1 in the greenhouse conditions. Radicle length and number of abnormal plants were determined as useful traits for screening germplasm for salt stress tolernace in laboratory. Sugar beet seed germination decreased to 35% and dead seedlings increased to 80% by growing seeds in sand medium at EC=16 dS.m-1 which showed the importance of sugar beet seedling survival in plant establishment in saline conditions. Seedling growth on Perlit, especially large size, was more vigorous than in sand. Genotypes: Bp Karaj, 7219 p.69, 436 Bigerm, 7233 p.29, 191and hybrid 7233 p.29 × MSc2, 9597 p.12, 428 OT, 452, 8150 p.9 and 7221, were identified as suitable germplasm for further experiments.