Glucosinolates are secondary plant products of the Brassicaceae that may influence vegetable flavor and human health. Soil moisture levels and plant water status are thought to influence cabbage head glucosinolate levels. However, no information is available on the effect of irrigation timing relative to plant developmental stage on glucosinolate concentrations in cabbage. To address these gaps in the literature, cabbage (cv. Bravo) was grown in 2002 and 2003 at The Ohio State Univ., Ohio Agricultural Research and development Center in Wooster, Ohio. The four irrigation treatments, arranged in a RCB design, were: 1) irrigation throughout development [no stress (NS)], 2) irrigation only during head development [frame stress (FS)], 3) irrigation only during frame development [head stress (HS)], and 4) no irrigation [frame and head stress (FHS)]. Irrigation was supplied via drip tape and scheduled by the hand-feel method. Differential soil moisture levels among treatments were confirmed with gypsum block, time domain reflectometry (TDR) and gravimetric measurements. Analyzed across years, irrigation timing significantly affected total glucosinolate concentrations, with levels 36% greater in cabbage not irrigated during head development (HS, FHS) relative to cabbage receiving irrigation during head development (NS, FS). Concentrations were highest (29.4 mmol·kg-1) and lowest (19.4 mmol·kg-1) in FHS and FS cabbage, respectively. Irrigation effects were greater in 2002, when air temperatures were higher and rainfall and relative humidity lower than in 2003. We conclude from the data that head development is the critical stage at which irrigation should be applied in order to influence cabbage glucosinolate levels at maturity.
T.J.K. Radovich, M.D. Kleinhenz*, and J.G. Streeter
T.J.K. Radovich*, M.D. Kleinhenz, J.G. Streeter, and M.A. Bennett
Cabbage (cv. Bravo) was grown in 2002 and 2003 at The Ohio State Univ., Ohio Agricultural Research and development Center in Wooster, Ohio. The four irrigation treatments, arranged in a RCB design, were: 1) irrigation throughout development [no stress (NS)], 2) irrigation only during head development [frame stress (FS)], 3) irrigation only during frame development [head stress (HS)], and 4) no irrigation [frame and head stress (FHS)]. Irrigation timing relative to crop stage significantly affected all head characteristics except density, with the greatest differences between cabbage receiving irrigation during head development (NS, FS) and cabbage not irrigated during head development (FHS, HS). On average, heads from NS and FS plots were heavier (38%), larger (15%), less pointed and had less volume occupied by the core than heads from HS and FHS plots. Combined head fructose and glucose concentrations were significantly greater in cabbage receiving irrigation during head development than in cabbage not irrigated during head development (47% vs. 41% dwt, respectively). Sucrose concentrations were significantly greater in cabbage not irrigated during head development than cabbage receiving irrigation during head development (8% vs. 6% dwt, respectively). The higher ratio of sucrose: fructose+glucose observed in HS and FHS relative to NS and FS treatments was interpreted as an osmo-regulatory response with potential implications for cabbage flavor. Overall, it was concluded that physiological responses elicited in cabbage by differential irrigation can affect important head traits, and that targeted applications of water during specific stages of crop development may be utilized to maximize water use efficiency and crop quality.
Matthew D. Kleinhenz and Annette Wszelaki
Yield and relationships among head traits were recorded in order to better understand the effects of planting date and cultivar selection on crop quality characteristics and to help increase the efficiency of cultivar development, evaluation, and selection. A total of seven cultivars of fresh market-type cabbage (Brassica oleracea L., Capitata Group) were planted in May and June of 1999 and 2000 at the OARDC Vegetable Crops Research Branch in Fremont, Ohio. Total and marketable yield, head traits (e.g., size, weight, density), and core dimensions were recorded at harvest. Main effects of year (Y), planting date (PD), and cultivar (C) and the Y × C interaction significantly affected seven to 10 of 10 head and core traits. However, the PD × C interaction was significant for head density, the ratio of head polar and equatorial diameter, and core base width. The Y × PD interaction was significant for six of 10 head and core traits. May planting tended to result in greater yield and larger, heavier heads with greater polar/equatorial diameter values relative to June planting. However, head density was unaffected by planting date. The number of head and core traits affected by planting date differed among cultivars. For example, six of 10 head and core traits were significantly affected by planting date in `Cheers' and `DPSX315' while one trait was affected by planting date in `SuperElite Hybrid'. The weight of numerous, individual, market-ready, trimmed heads showed a strong (avg. R 2 value = 0.92) quadratic relationship to average head diameter. These data suggest that large-scale germplasm evaluations may benefit by including multiple plantings, as head weight, volume, diameter, and shape were affected by planting date, possibly due to variation in temperature and rainfall patterns. The data also suggest that routine measurement of numerous head traits in the same evaluations may be unnecessary, as selected traits (e.g., diameter and weight, head volume, and core volume) were strongly related.
Annette Wszelaki and Matthew D. Kleinhenz
This is the second of two related reports dealing with the effects of cultivar × environment interactions on cabbage (Brassica oleracea L., Capitata Group) crop traits. This study examined planting date and cultivar effects on physical head traits of processing cabbage and compared these findings to those from a similar study of fresh market cabbage. Six cultivars of processing cabbage were planted in May and June-July of 1999 and 2000 at the OARDC Vegetable Crops Research Branch in Fremont, Ohio. Marketable yield for each crop was determined, and measurements were taken of head weight, diameter, density, and volume, and core length, base width, and volume on more than 450 individual heads. Head and core volume and head density were calculated from these direct measures. Year, planting date, and cultivar significantly affected the majority of head traits. May planting led to higher marketable yield and heavier heads with larger diameters than June-July planting. The most variable trait across cultivars was head volume, which was affected by planting date in all cultivars. Differences between processing and fresh market cabbage were found. Average head polar/equatorial diameter values were affected by planting date in the fresh market but not the processing study. In contrast, head density and core volume as a percent of head volume were affected by planting date in the processing but not the fresh market study.
Vincent A. Fritz, Veronica L. Justen, Ann M. Bode, Todd Schuster, and Min Wang
concentrations in six commercial cultivars of cabbage ( Brassica oleracea L., Capitata group) HortScience 40 106 110 Rosen, C.J. Fritz, V.A. Gardner, G.M. Hecht, S.S. Carmella, S.G. Kenney, P
Regina P. Bracy, Richard L. Parish, Paul E. Bergeron, E.B. Moser, and R. J. Constantin
Field studies were conducted in Spring 1989 and 1990 to determine if cabbage (Brassica oleracea L. Capitata Group) could be precision-seeded to a stand without subsequent thinning and to determine the optimum seed spacing necessary to seed cabbage directly to a stand. Seed spacings of 10, 20, and 30 cm at one seed per hill and 30 cm at two seeds per hill were evaluated for effect on yield, head weight, plant population, and harvest percentage. Seeder precision (accuracy) with regard to seed counts and spacing measurements at the various seed spacings, as evaluated in the laboratory, was good. Seeder precision evaluated in the field varied in distribution patterns among seed spacings and years. Cabbage directly seeded at one seed per hill and a 30-cm spacing produced yields and head weights similar to or higher than cabbage seeded 10 cm apart and thinned to 30 cm-the seeding method currently used by some commercial operators.
Rogério L. Cansian and Sergio Echeverrigaray
Randomly amplified polymorphic DNA (RAPD) markers were used to discriminate among 16 commercial cultivars of cabbage (Brassica oleracea L. Capitata Group). A set of 18 decamer primers was selected from 100 random sequences and used to characterize cultivars and to evaluate distances. The selected primers produced 105 (54%) polymorphic bands ranging in size from 100 and 2500 base pairs, out of a total of 195 bands, which allowed for discrimination of all cultivars. Similarity indices between cultivars were computed from RAPD data, and ranged from 0.72 to 0.87 with an average of 0.82. Unweighted pair-group method with arithmetic average (UPGMA) cluster analysis revealed two groups, one formed by two cultivars recommended for summer cropping, and the other by 14 cultivars. This large group was additionally divided into two subgroups. RAPD analysis provides a quick and reliable alternative for the identification of cabbage cultivars and for determination of the relationships among them.
Reeser C. Manley and Rita L. Hummel
The index of injury (It) and tissue ionic conductance (gTi) formulas for analyzing electrolyte leakage data from freeze-stressed tissues of cabbage (Brassica oleracea L. Capitata group) were compared. The two formulas produced similar results in calculating the relative freezing responses of stem pith, lamina, and petiole tissues. Disagreement occurred only with lamina tissues when the magnitude of ion leakage was low. Vital staining of pith and petiole tissues with triphenyl tetrazolium chloride indicated that the tissue TK50 (the temperature resulting in 50% injury), derived from It data, was a reliable indicator of the freeze-killing point. These results support the use of the simpler It method for analyzing electrolyte leakage data in studies of cabbage freezing tolerance.
Regina P. Bracy and Richard L. Parish
Stanhay, Carraro, and Gaspardo precision vegetable seeders were evaluated for seeding uniformity with seeds of five vegetable crops—cabbage (Brassica oleracea L. Capitata group), carrot (Daucus carota L.), cucumber (Cucumis sativus L.), onion (Allium cepa L. Cepa group), and spinach (Spinacia oleracea L.). Five measurements [mean, percentage of misses, percentage of multiples, quality of feed, and precision (defined as the coefficient of variation after misses and multiples were discarded)] were used to evaluate seeder uniformity. Using all five measurements provided a more complete determination of the metering uniformity of the seeders than was possible in prior work when only mean and coefficient of variation were used. The belt seeder (Stanhay) was effective at singulating spherical seeds (cabbage) and nearly spherical seeds (onion)as the most precise vacuum seeder (Carraro). Seeding uniformity of all seeders with elongated (carrot and cucumber) or angular (spinach) seeds was inadequate for precision seeding.
Regina P. Bracy, Richard L. Parish, and Joe E. McCoy
Precision vegetable seeders were found to have unexpected variation in seed spacing uniformity. A belt seeder and vacuum seeder were evaluated using cabbage (Brassica oleracea L. capitata group) seeded at different seed spacings to determine if seeder uniformity improved with increasing seed spacing. Seeding uniformity of the belt seeder was not affected by seed spacing, but uniformity of the vacuum seeder was. Variation in seed spacing with the vacuum seeder was consistent in absolute units, thus seed spacing nonuniformity (expressed as a percentage of theoretical spacing) decreased with increasing seed spacing. Operating the vacuum seeder with the air pressure seed release mechanism disengaged improved seeder precision. Uniformity and precision of the belt seeder were better than that of the vacuum seeder.