Relationship between branching pattern and flowering habit of multigerm pollen parent lines in sugar beet [Beta vulgaris]

In order to improve the seed production and seed quality of a sugar beet F1 hybrid, the branching pattern and flowering habit of related parent lines are of significant knowledge and information. Relationship between branching pattern and flowering habit in diploid and tetrapioid multigerm pollen parent lines were investigated. In addition, the effects of early top pruning of main stem of pollen parent lines on the number of indefinite bud, flowering habit, and quality and quantity of pollen were examined. From the result, the tetraploid pollen parent line "NK-217BR" was found to have a few more primary and secondary branches than diploid pollen parent line "NK-212BR", and no thirdly branches were observed. From these observations, "NK-217BR" was considered less vigor. As for the flowering habit, both of the pollen parents indicated similar features irrespective of their polyploidy. Namely, for each of the pollen parent, flowering initiation corresponded to the time when flower buds at the tip of a main stem in Group 4 and Group 5 started blooming. Flowering time was the time when flowers at the tip part of primary branches in Group 1 and Group 3 began blooming. Prime flowering time matched the time when flowers at the tip part of secondary branches in Group 1 and Group 3 commenced blooming. Accordingly, the flowering habit was made clear by investigating the bloom of flowers on the specific branches. However, since the date of flowering initiation of "NK-217BR" was 4 days later, and the flowering time and the prime flowering time were 1 day and 3 days earlier respectively than those of "NK-212BR", flowering period of the former was thought to be a little shorter than the latter. Whereas, the effects of top pruning was not observed on the number of indefinite buds, but the flowering initiation date of "NK-217BR" delayed for about 2 days on every branch, and decrease of amount of pollen dispersal was induced in both pollen parents. So it was concluded that effects of top pruning were different in pollen parent lines, but this technique was considered useful for adjusting flowering period of pollen parent in use of sugar beet F1 seed production.