Performance of ten sugar beet varieties for growth, yield and juice quality under different soil salinity levels

Soil salinity is affecting plant production, including sugar beet growing, especially in Al-Fayoum Governorate, Egypt. Screening for salinity tolerant varieties is one of the most often methods used by breeders in sugar beet. The present study was carried out at Al-Fayoum Governorate, (29°17ˋ N; 30°53ˋ E), Egypt, during 2017/2018 and 2018/2019 growing seasons. The objective was to evaluate the effect of saline soil of three locations (villages) S1, 3.57 dSm-1 (Monshat Sinnuris), S2, 8.6 dSm-1 (Monshat bani Othman), and S3, 11.84 dSm-1 (Monshat Tantawy) on plant growth, quality and yield traits of ten multigerm sugar beet varieties. The experimental design was a randomized complete block design with three replications. Results showed that root yield and sugar yield, as well as root dimensions were significantly decreased by increasing soil salinity levels as compared with the control treatment. Under severe soil salinity, Florima variety was superior in root and sugar yields [13.71 and 1.82 ton/fed (fed=0.42 ha)]; on the other hand, Euklid variety recorded the lowest values (11.38 and 1.39 ton/fed), respectively. As for the interaction between soil salinity levels and sugar beet varieties, the highest values for root and sugar yields were recorded by the varieties Florima, Toro, Cleopatra, and Tarbelli, under severe soil salinity (11.84 dSm-1). The results recommended the above four varieties to be cultivated by farmers under saline soil; these varieties are tolerant to soil salinity and they can produce stable root and sugar yields in the stressed soil. High broad-sense heritability estimates were obtained by extractable sugar (94.9%), root length (93.36%), and root weight (92.05 %). Heritability of metric traits is of great significance to the breeders as its magnitude indicates the accuracy with which a variety can be recognized by its phenotypic expression. Results showed that four varieties (Florima, Toro, Cleopatra and Tarbell (had a salinity susceptibility index (SSI) based on root and sugar yields of <1 and were relatively tolerant to salinity stress.