Comparative Performance Of Male And Female Plants During The Annual Growth Cycle Of A Dioecious Asparagus Cultivar

Male asparagus plants usually produce larger spear yields than females. We present results of a field experiment in which the yield difference between males and females in a mixed population was quantified and related to contrasts in key below-ground growth characteristics during the crop's annual cycle. Measurements were made in a Jersey Giant Syn 4 crop in which the sex of every plant was determined and mapped in the autumn of the third year. The male/female ratio in the population averaged 57:43. The spear yields of male and female plants were measured separately in three harvest treatments during the following season: spring, extended spring and autumn harvests. Whole root systems of male and female plants were excavated separately on seven occasions during the season and measurements were made of their dry weight, carbohydrate content and numbers of buds and roots.In all treatments, total spear yield per plant was about 80% higher for males than for females. This meant that males contributed about 70% of the yield per unit area in the mixed population. The yield difference between males and females was associated with large below-ground differences. Root system dry weight was almost twice as great for males, and the carbohydrate content of female roots was generally lower. Bud and root numbers per crown were also lower for females than males.