غربال كلون هاي كشت بافت چغندرقند براي تحمل به ساقه روي و بررسي اثر جيبرليك اسيد بر اين پديده

Screening of tissue cultured-clones of sugar beet for bolting tolerance and a study on gibberelic acid aimed to bolting of sugar beet

In this study, after propagation and producing tissue-culture clones obtained from seed population Jot 18 (pollinator tetraploid resistant to bolting), these clones were incubated in cold condition of 4-7°C for 12 and 15 weeks, and then were transferred to the greenhouse with 20°C and percent of bolted plants was determined. A randomized complete block design in three replications was used for statistical analysis. Percentage of bolting was calculated in 1 and 2 weeks after cold treatment duration. The result of 12 week incubation at cold condition showed that genotypes have significant differences after one or two weeks at 5% and 1% level respectively. The result of 15 week incubation at cold condition showed that genotypes have significant differences after one or two weeks at 1% level. Results showed that in two cooling period, genotypes B29 and B16 are tolerant and susceptible to bolting respectively. Use of colons having same genotype, resulted in increasing of selection accuracy of resistant genotypes. In this study for decrease need cooling period, for screening tolerance genotype to bolting in sugar beet used GA3 treatment. For this, three concentrations 0, 10 and 50 milimolar GA3 were inoculated for six times onto shoot apices of seedling of one-month cold pretreated. Factorial experiment in randomized complete block design was used in three replications. Percentage of bolting was calculated in five times at one-week interval after final inoculation step. The results of second week were used for screening of bolting tolerant plants. A statistical level was 1% and result of the second week note- taking indicated that GA3 and genotype effects are significant at 1% level and GA3 genotype interaction did not have significant differences. As a result, Genotypes was classified in three groups: susceptible, semi tolerant and tolerant. As a result 50 concentration milimolar had more effective on bolting sugar beet and breeder can use GA3 as a substitution for part of cold duration and reduce breeding time for bolting screening and increase selection efficiency.