An investigation on different planting dates in decrease rhizomania disease damage on sugar beet ( Beta vulgaris L. )
2006
Ashraf Mansoori, Gholam Reza | Niromand Jahromi, Mahmud | Darabi, Saeed | Joukar, Ladan | Fath Ol-Lah Taleghani, Daryush
In order to investigation the effects of different planting dates and three sugar beet cultivars on reduction of damage Rhizomania disease, a split plot experiment (with RCBD as the base design) was conducted in infected and uninfected fields. The treatments were composed of four different planting dates (10th of March, April and May) and as a minor objective, the effect of cultivar transplantation on their Rhizomania tolerance was also studied in 10th of March planting date as main plots and three sugar beet cultivars (7233, Rhizofort and Dorotea) as sub plots. In sub plots, every cultivar was sowed in four rows, each 9m long. The 12 treatments were replicated four times and studied during three years During the growing period, parameters such as number of plants, lost plants were determined, and the amount of plant coverage was determined by measuring the amount of light above and below the plant canopy. The root yield was measured by harvesting the roots from the middle of plots (from two row, each eight meter long). Characters such as root yield, sugar content, impurities (K, Na and damaging N in pulp), white sugar percent, purity of raw extract, alkali index, molasses, the dry and wet weight of shoot and virus concentration (by using Elisa Test) were determined. Results of uninfected field showed that the root yields from different planting dates were significantly different (at 1% level of probability) The maximum and minimum root yield correspond to 74.39 and 66.62 T.ha-1 were obtained from the plots of 10th of April and May respectively. The Rhizofort root yield of 89.21 T.ha-1 sowed in 10th of April root was the highest among the cultivar under study, which also resulted to the highest white sugar yield. In infected field, there was no significant different in root yield and sugar content among planting dates. The highest sugar content (11.38%) was obtained from 10th of April plot. The highest root yield of 47.94 T.ha-1 was obtained from the cultivar Dorotea sowed on 10th of April. Rhizofort and Dorotea had the lowest concentration of virus, but the susceptible cultivar of 7233 had the highest concentration. (light absorption of 0.7941 nanometer). The dry and wet weight of Dorotea shoot was higher than other cultivars. The mean root yield of 7233 cultivar, in infected field was 12.71 T. ha-1, while transplanting of this cultivar in uninfected and infected field has yielded 52.24 and 17.59 T.ha-1 respectively. The sugar content, white sugar yield, virus concentration, shoot dry and wet weight of 7233 in infected field was completely lower than two other cultivars. Comparison of common characters in uninfected and infected field by T-Test showed that root yield, sugar content and white sugar yield are significantly different: root yield of 71.49 versus 33. 44 T.ha-1sugar content of 14.13 versus 11.13% and white sugar yield of 7.2 compared with 2.61 T.ha-1.respectively.
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