Correlation of Early Growth with Average Germination Period and True Seed Weight in Sugar Beet under Direct Sowing Cultivation.

Abstract

The relationship between early growth and seed characters was examined in 69 three-way crossed hybrid lines and three varieties. In all plants examined, total dry weight of the plants in the early growth period tended to be larger, the heavier the true seed weight and the shorter the average germination period. The effect of germination period on early growth was larger than that of true seed weight on the basis of standard deviation, and the true seed weight mainly affected the growth of the very early growth period. In hybrid lines, the true seed weight was largely affected by single-crossed seed-parent lines rather than pollen-parent lines including tetraploids, and their interactions were small. On the other hand, no significant correlation was observed between true seed weight of seed-parent lines, whose seeds were produced on the bolting stem of cytoplasmic male -sterility lines, and their descendant hybrid lines, whose seeds were produced on single-crossed seed parent lines. The hybrid lines generally had a heavier true seed weight than their seed-parent lines. It was considered that heterosis effect of the first cross between cytoplasmic male-sterility lines and male-sterility-maintaining lines was expressed in the true seed weight of three-way-crossed hybrid lines. The three-way cross method might be suitable for breeding of a large true-seed variety in sugar beet.