Response of sugar beet multigerm genotypes to salinity stress

Nowadays it is focused on sugar beet monogerm varieties because of mechanization improvement In Iran, but it couldn't be said that monogerm root and sugar yields are more than multigerm varieties. In some experiments, root yield of monogerm sugar beet varieties are more, equal or even less than multigerm ones. Although sugar and white sugar yields of monogerm sugar beet varieties are similar to multi germ in most experiments and sugar beet seed germ based on mono or multi doesn't affect on sugar purity percentage. Beet production areas such as clay texture lands are still dedicated to multigerm varieties. It is recommended to use multigerm varieties to alleviate undesirable environmental effects such as drought and salinity stress to have better plant germination and establishment. Improvement of salt tolerant multigerm varieties could be very important to decrease the effect of this stress on sugar beet. Therefore, screening of sugar beet multigerm germplasm under saline condition to develop multigerm varieties is necessary.

In this study, 20 sugar beet multigerm genotypes were evaluated under normal and saline conditions (EC=20 dS/m) in factorial experiment based on completely randomized design with four replications. Two seed germination methods including fast germination test in Erlen and between paper tests, used in laboratory. Then, the genotypes were compared under normal and saline (EC=16 dS/m) conditions in four replications in greenhouse. Samples took two months after stress initiation at establishment stage (8-10 leaves). Shoot and root fresh and dry weights, Na, K, K/Na and total soluble carbohydrate of leaves measured.

7233, AMP2 and PB13-S2-151-HSF-91genotypes had the highest field emergence potential (FEP) with 0.176, 0.09 and 0.05, respectively. Salinity decreased total, shoot, and root dry weights, K and soluble carbohydrate by 20, 24, 6 42 and 38 percent respectively and increased Na and P by 400 and 11 percent, respectively. Finally, the genotypes PB 13S2-151-HSF 915, 7233, S1–930882, S1–931008, Poly8823, S1–930770, Gazale, S1–930910, 5RR-87-HS-28 and S1–930792 were selected as tolerant materials based on fast germination and between paper germination tests, yield and biochemical traits. Some of selected genotypes were evaluated and been selected under drought or saline stress studied in field experiments but result of field experiments could be achieved after 7 months while the result of this experiment was taken after two months. So, the similarity of result of this experiment with field tests showed that fast genotype screening in green house could be useful for accelerating breeding of salt tolerant varieties.