Varietal Differences in Underground Shoot Branching Characteristics and their Relation to Harvest Characteristics in Asparagus Crowns

In general, either high or low branching may contribute to the yield potential of a cultivated crop. In this study, we evaluated the varietal differences in branching characteristics in asparagus crowns and examined the relationship between branching types and harvest characteristics among six varieties tested by careful observation. ‘UC 157’ developed numerous tillers and shoot apical meristems 6 months after sowing; thus, it was considered to be a high-branching type variety. In contrast, ‘All-male Gulliver’ and ‘Ryuryoku’ developed few tillers or shoot apical meristems and, were therefore considered to be low-branching type varieties. The final order of sympodial shoots and composition of sympodial shoots by order were similar between the varieties. ‘UC 157’ had fewer scale leaves attached to the underground shoots than other varieties, which may have been advantageous for developing underground shoots more rapidly. The total spear yield of ‘UC 157’ was high, but the marketable spear yield was similar to that of other varieties owing to the large number of thin spears. Although further studies are needed to determine whether high-branching or low-branching type asparagus varieties are more high-yielding, we determined that high-branching type varieties have lower labor productivity under unimproved growing conditions such as non-sparsely planted growing conditions.