IMPACT OF GROWING SEASON ON GENOTYPIC DIFFERENCES IN SUGAR BEET

A small-parcel experiment was established in Velke Ripnany. Six varieties (Ambition, Cambria, Delano, Modex, Mandarin and Ventura) of Danish company Maribo Seed were seeded using the Oyord sowing machine on 31 March in the monitored year 2011. Right after the sowing there was a big rainfall deficit, which made the seedling emergence more complicated. Germination improved after the subsequent rainfall, the cover was completed, but the growth was uneven. Ample rainfall was monitored in the early summer months: June and July. The cover was fungicidally treated and health conditions were thus very good in comparison with the untreated cover. Harvest was carried out from 18 to 20 October 2011 in two phases: by machine and by hand. During the experiment, the influence of environment on differences of sugar beet cultivars was monitored. Root yield represents a production proces indicator that is sharply influenced by weather during crop emergence and by genetic qualities of the varieties. The Ventura variety (92.3 tha(-1)) reached the highest level of root yield of the evaluated varieties; this variety also reached the highest yield index (99.29%) in the given period within the whole experiment. The average root yield of the monitored varieties was 86.07 tha(-1). The best sugar content was monitored in Modex variety (19.54%); on second place there were two varieties: Cambria (19.17%) and Mandarin (19.11%). The average sugar content of all varieties reached 19.03%, which was also to a certain extent influenced by the high temperatures with low rainfall totals. Ventura and Cambria varieties (15.80 and 15.42 tha(-1)) had the highest white sugar yield of the monitored varieties. The lowest levels were monitored in Modex and Mandarin varieties (13.93 and 14.92 tha(-1)). The given data proves that Ventura variety reached the highest harvest index in the experiment year and shows the best average values of the monitored parameters (root yield, polarized and white sugar yield). Results of the analysis thus suggest that it is important to continue monitoring the impact of climate changes on sugar beet in the future with respect to choice of proper genotypes for the particular growing areas.