Abstract:
It is well known that sugar beet is sensitive to salinity stress at the germination stage.
Three separate experiments were conducted to study the effects of salinity on seed
germination, plant establishment, and yield of sugar beet genotypes for screening
purposes. These included: (a) A laboratory study using four water salinity levels (with EC
values < 0.1 as the control, 16, 20, and 24 dS m-1) with 20 sugar beet genotypes, which
were evaluated in a factorial completely randomized design with four replications, and
seedling characteristics were measured; (b) A greenhouse experiment where the same
statistical design as the lab study was used for seed germination and establishment of 19
sugar beet materials, with irrigation water EC= 3 and 16 dS m-1; and (c) A field
experiment that was carried out to study the response of nine selected genotypes to
irrigation waters with EC= 4 and EC= 16 dS m-1, using a split plot design with three
replications. Interaction effects of salinity and genotypes were statistically significant (α=
0.01) for percentage of germination, abnormal seedling, and root and hypocotyls lengths.
Indeed, sugar beet germination decreased to 35% and dead seedlings increased to 80 %
under salinity stress (EC= 16 dS m-1) in the greenhouse. Genotypes were ranked from
tolerant to susceptible. The results of field experiment were consistent with that obtained
in the greenhouse. It can be concluded that salt stress decreased seed germination and,
later on, crop establishment by increasing dead seedlings; consequently, sugar beet yield
decreased. It seems that establishment is more susceptible to salinity than germination.
Root length and abnormal seedling are good indexes for screening sugar beet genotypes
for salinity tolerance at the primary growth stages.
Keywords: Abnormal seedlings, Crop establishment, Root length, Saline irrigation water.
