Important Cabbage Head Traits and Their Relationships at Five Points in Development

We set out to document events and relationships among key traits throughout cabbage head formation, particularly in early stages, in order to help develop and implement efficient strategies to increase crop yield and quality. Head traits used as indicators of horticultural maturity and crop quality were documented at five stages of development in 3 commercial fresh market/slaw and processing cabbage cultivars grown in 2001 and 2002 at The Ohio State University, Ohio Agricultural and Development Center in Wooster, Ohio. Seedlings containing 2–4 true leaves were planted in June of both years. Trait measurement began 35 days prior to the estimated market maturity date for each cultivar and continued weekly for five weeks. Harvest timing affected all head traits evaluated. Head weight, diameter, volume, and density and core volume generally increased with harvest date, while the ratio of head polar to equatorial diameter and the percent of head volume occupied by the core decreased. A strong curvilinear relationship between head mean diameter and head weight was found. Developmental changes in head density, in contrast to weight and size, were found to be largely independent of thermal time. Information gained in this study adds to our understanding of cabbage crop development. It also strongly suggests that accurate assessments of developmental stage during the scheduling of harvest are required to maximize head quality. The results also indicate that head growth and maturation should be viewed as separate and distinct concepts in discussions of head development.