Investigation of sugar beet (Beta vulgaris L.) monogerm hybrids produced under different climatic conditions for drought resistance at germination stage and seedling growth

IIntroduction In many herbaceous species, the seeds are different in terms of germination capacity inside and between species and also inside the mass. Some of these variations may have a genetic origin, but many of them are related to the phenotypic characteristics of the seeds, which is caused by the local conditions in which the maturity of the seeds has taken place. These conditions include the combination of the microclimate that the seed experiences according to its position on the mother plant, also due to environmental conditions of the plant (environmental temperature, daytime, water availability, etc.). Some of the physiological and agronomic characteristics of plants play a role in their drought tolerance, and these characteristics are used to select drought-tolerant genotypes. One of the most important characteristics of drought tolerance is seed germination and seedling development under conditions of inaccurate moisture. Due to the proper establishment of seedling in the field and the production of vigorous seedlings indirectly related to the higher yield of the plant. This research was conducted to investigate the reaction of sugar beet monogerm hybrids produced in different climatic conditions to drought stress in the germination stage and seedling growth and to compare the hybrids obtained through crossing between advanced lines under different climatic conditions. Materials and Methods This research was conducted in 2014 as factorial based on randomized complete block design with three replications at the Laboratory of Seed Technology at Ardabil Sugar Beet Processing and Preparation office under laboratory conditions. . Experiment was carried out as factorial based on randomized complete block design with three replications. The factors included 20 hybrids seed (hybrids derived from the cross of five promising diploid cytoplasmic male sterile (CMS) lines (7112×SB36, SB37×28874, 7112×436, 419×SB36 and 261×231) and four diploid, pollinator lines (SHR.1-P12, F-8662, FC709-2/24 and S1-88239) which was produced in two regions of Ardebil and Karaj. and drought stress levels (control, -2, -4, -6 and -8 bar). Germination parameters were estimated in pleated filter paper and seedling growth parameters (root, shoot and weight) were evaluated in paper towels. Results and Discussion The results of the experiment showed although the percentage of germination in seed produced at Karaj station was far lower, but the important point in this research was that the germination velocity in seed produced at Karaj seed production station was higher than the seeds produced in Ardebi. Germination percentage, germination rate, percentage of emergence, root length and hypocotyl and seedling dry weight in different hybrids produced in both regions decreased with decreasing of water potential and the time to germination and abnormal seedling percentage increased However, the amount of reduction in seeds from different areas of seed production was different, and in seeds produced in Ardebil, the reduction in germination and seedling growth was lower than the seeds produced in Karaj. Among the hybrids produced in both regions, hybrid 7112*436×SHR01-P.12 had the highest and hybrid 419*SB36×S1-88239 had the lowest germination percentage, and the hybrid 261*231 × SHR01-P.12 and 28874*SB37 × SHR01-P.12 had the highest and lowest germination rates, respectively. Conclusion The results of this experiment showed that germination percentage and seedling growth indices in the seeds produced in Karaj region were significantly lower than the seeds produced in Ardebil. Moreover, the tolerance to drought stress was also observed in seeds produced at the station Karaj was lower. Among the seeds of hybrids produced in both regions (Ardebil and Karaj) under severe drought stress, hybrid of 7112*436 × SHR01-P.12 had the highest germination percentage and seedling growth, and among the hybrids produced in each two regions of seed production and in all moisture treatments, hybrids 261*231 × SHR01-P.12, 261 * 231 × F-8662, 261 * 231 × FC709-2 / 24 and 261 * 231 × S1-88239, have the highest germination rates