Genotype and Planting Date Effects on Fresh Market and Processing Cabbage Yield, Head Traits and Sensory Quality in Ohio

 

M.D. Kleinhenz, B. Schult, T.J. Radovich, A. Sanchez-Vela, and J.C. Scheerens

Department of Horticulture and Crop Science

The Ohio State University

Ohio Agricultural Research and Development Center (OARDC)

Wooster, Ohio

 

Introduction

 

Cabbage production for fresh, slaw, and kraut markets is a large and vital part of the Ohio vegetable industry, especially in the northwest and south-central regions of the state. Strict market quality standards and Ohio’s long cabbage season (late March-mid November) requires that growers select varieties not only desired by the market but also adapted to a wide range of environmental and production conditions. This project was undertaken to provide the Ohio cabbage industry with information useful in variety selection. This information may also help to improve our understanding of genotype and environment effects on cabbage yield and quality.

 

Materials and Methods

 

See Tables 1 and 2 for a list of the genotypes examined in the fresh market and processing studies.

 

Transplant Production. Entries were solicited from cooperating seed companies in winter 1999-2000. Transplants were seeded in spring, allowed to develop 2-4 true leaves in the greenhouse, and hardened-off before planting into the field.

Plot Establishment. A randomized complete block design was used in each study. Each study contained four replications per entry per planting and two planting dates (fresh market -- May 12, June 30; processing -- May 15, July 6). The fresh market study included twenty-four genotypes and the processing study included twelve genotypes. Two-row plots were established with a cone-type two-row transplanter. Each row was 15 ft. long with 30 in. between rows and 11 in. (fresh market) and 18 in. (processing) between transplants. A 0-46-0 fertilizer was used to supply 60 lb. P2O5 and a 0-0-60 fertilizer was used to supply 250 lb. K2O in September 1999. Ammonium nitrate was broadcast to supply 70 lb N/A on May 5, 2000. A nutrient starter solution (0.7 qt. 10-34-0/50 gal. water) was delivered next to the transplants.

Plot Maintenance. Dead transplants were replaced (if possible) within one week of initial planting. Standard pest management strategies based on scouting, thresholds, and application of labeled pesticides were employed.

Data Collection (Field). Plots were reviewed twice per week to assess development. Notes on plant stature, head shape, and other traits were taken on mature entries immediately prior to harvest.

Data Collection (at Harvest). Harvest readiness for individual entries was estimated from published maturity information and visual examination of the five plots per entry. At maturity, all heads were collected from within the center 10 ft. of both rows in each plot. Heads were scored as marketable or unmarketable (too small, split, rotten, or containing evidence of blackrot or tipburn) and weighed as a group. Ten marketable heads were then selected at random from the harvested group for further evaluation. Five outer leaves were removed from each head before they were re-weighed individually. Heads were then cut in half longitudinally and the core length and base width as well as the head  polar and equatorial diameter of each head recorded.

Additional Quality Analysis. Two additional marketable heads from each plot were collected at harvest and sent to The OSU Food Industries Center for further evaluation (fresh market study only, data available upon request). In 2001, parallel studies were completed using similar methods but different genotypes. Estimates of cabbage sensory quality were obtained on randomly selected heads of marketable external quality (fresh market study only). Untrained panelists scored the overall desirability of samples and their acceptability based on flavor, aroma, texture, and color. Linear scales were also used to quantitatively describe flavor components (hot, sweet, bitter, crisp) relative to a known reference (cv. Bravo) which was also included as a sample. In 2000 and 2001, tissue from one marketable head from each plot was prepared for isothiocyanate analysis (fresh market study only). Isothiocyanates are among the compounds known to contribute to cabbage flavor. Consumption of food products thought to contain high levels of isothiocyanates, such as cabbage, is also thought to have specific health benefits.

Statistical Analysis. Head density was estimated through calculation using replicate averages of head weight and polar diameter. Likewise, the percent of the head volume contained in the core was estimated through calculation using replicate averages of head polar diameter and core length and base width. Replicate averages were calculated and used in means analysis. Main effects and interactions of planting date, entry, and replicate were analyzed with fully specified model statements in SAS (alpha = 0.10). The Fisher Least Significant Difference test (alpha = 0.10) was used to analyze the effect of planting date and replicate while the Duncan Multiple Range test (alpha = 0.10) was used to analyze the effect of entry.

 

Results

 

Fresh Market Study

 

Data are contained in Tables 4-9 [see 4 and 5 below, 6 , 7 , 8 , 9 ]. The planting date-x-entry interaction was significant (alpha = 0.10) for five of seven head and core traits but not significant for marketable or total yield (Table 4). Planting on May 12 versus June 30 tended to result in larger, heavier heads and greater total and marketable yield (Table 5). Planting date, though, did not effect head density or core volume (Table 5). Core volume was relatively constant at approximately 1% of head volume. Marketable yield in the May planting ranged from 20.3 ton/A to 59.0 ton/A (Table 6). Marketable yield in the June planting ranged from 6.6 ton/A to 31.9 ton/A (Table 6). Marketable yield for twelve of twenty-four entries was similar after planting in May versus June and head density was similarly unaffected by planting date in fourteen entries (Table 9). In three entries, none of the nine traits studied were impacted by planting date (Table 9) while in five entries six of nine traits were effected by planting date (Table 9).

 

Processing Study

 

Data are contained in Tables 10-16. [see below for 10 and 11, 12 , 13 , 14, 15 , 16 ] The planting date-x-entry interaction was significant (alpha = 0.10) for total and marketable yield and five of seven head and core traits (Table 10)[below]. Planting on May 15 versus July 6 tended to result in heavier, more dense heads with larger cores and greater total and marketable yield (Table 11)[below]. Planting date, though, did not effect calculated core volume (Table 11). Core volume was relatively constant at approximately 1% of head volume. Marketable yield in the May planting ranged from 25.1 ton/A to 46.0 ton/A (Table 12). Marketable yield in the July planting ranged from 19.6 ton/A to 34.2 ton/A (Table 13). Marketable yield for seven of twelve entries was similar after planting in May versus July and head density was similarly unaffected by planting date in eight entries (Table 16). In all entries, at least one of nine traits studied was effected by planting date (Table 16). In four entries, at least six of nine traits were effected by planting date (Table 16).

 

Discussion

 

That planting date influenced yield and most head traits in 2000 was consistent with results from similar studies in 1999. Studies to better explain this trend are underway, focusing on the response of cabbage head development to abiotic factors, including temperature. The 2000 season was generally characterized by below-average temperatures and above-average rainfall (Table 3). It is likely that temperature or moisture imbalances at critical stages of crop development contributed to reduced yield and/or quality in some genotypes. The influence of planting date on yield and head traits suggests that selection of varieties for specific plantings (i.e., early-, mid- and late-season) may be warranted. For example, the three top-ranked varieties based on marketable yield for each market type differed in the spring and summer planting (fresh market spring = Cheers, Matsumo, Green Cup; fresh market summer = Superelite Hybrid, Cheers, Blue Thunder; processing spring = Geronimo, NIZ 95-23, Almanac; processing summer = Hinova, HMX 0221, Score). Variables in addition to marketable yield must also be considered in selection, including those related to physical, chemical, and sensory quality (e.g., flavor, vitamin C content, texture) and resistance to diseases, insects, and physiological disorders. Genotype and planting date effects on a number of these variables are currently under study in Ohio. Preliminary results from consumer taste panels completed in 2001 suggest that, overall, genotype and planting date explain a large amount of the variation in cabbage desirability and that the effect of planting date is similar among varieties. Preliminary results also suggest that flavor acceptability is more strongly correlated with overall sample desirability than the individual and combined effects of texture, aroma and color.

 

Table 4. Influence of planting date and entry on yield and head traits for twenty-four genotypes of fresh market cabbage planted on May 12 and June 30, 2000 at the OSU Vegetable Crops Research Branch in Fremont, OH.

 

 

---------------------- head ---------------------          ------------------- core ------------------

-- yield (ton/A) ---        weight     density           -- diameter (cm.) --      length   base width            % of

Source                         df         marketable       total        (kg)       (g/cm3)          polar       equatorial       ------- (cm.) -------            head volume

 

 

--------------------------------------------------------- Pr > F ---------------------------------------------------------

 

Planting Date (PD)          1        <0.0001       <0.0001   <0.001   0.4546          <0.0001     <0.0001       0.9427    <0.0001               0.5227

 

Entry (E)                      23        <0.0001       <0.0001   <0.001   0.0003          <0.0001     <0.0001     <0.0001    <0.0001            <0.0001

 

PD x E                         23          0.6176         0.1857   <0.001   0.0119            0.0273       0.3848       0.7587    <0.0001            <0.0001

 

 

 

Table 5. Influence of planting date on yield and head traits for twenty-four genotypes of fresh market cabbage planted on May 12 and June 30, 2000 at the OSU Vegetable Crops Research Branch in Fremont, OH.

 

 

---------------------- head ---------------------          ------------------- core ------------------

-- yield (ton/A) ---        weight     density           -- diameter (cm.) --      length   base width            % of

Planting Date                N         marketable       total        (kg)       (g/cm3)          polar       equatorial       ------- (cm.) -------            head volume

 

 

May 12, 2000              72          37.6 a            40.2 a     2.3 a    1.13 a           15.9 a          17.1 a       7.8 a          3.16 a            1.00 a

 

June 30, 2000              72          21.3 b            28.5 b     1.6 b    1.06 a           14.6 b          16.0 b      7.8 a          2.82 b            1.02 a

 

L.S.D.(0.10)                        2.68               2.50      0.10     0.14                0.28            0.35        0.22           0.06            0.04

 

Table 10. Influence of planting date and entry on yield and head traits for twelve genotypes of processing cabbage planted on May 15 and July 6, 2000 at the OSU Vegetable Crops Research Branch in Fremont, OH.

 

 

---------------------- head ---------------------          ------------------- core ------------------

-- yield (ton/A) ---        weight     density           -- diameter (cm.) --      length   base width            % of

Source                         df         marketable       total        (kg)       (g/cm3)          polar       equatorial       ------- (cm.) -------            head volume

 

 

--------------------------------------------------------- Pr > F ---------------------------------------------------------

 

Planting Date (PD)          1        <0.0001         0.0348     0.0024   <0.0001       <0.0001       0.8887       0.0124    <0.0010            0.4027

 

Entry (E)                      11        0.0027          0.0023   <0.0001   <0.0001       <0.0001     <0.0001     <0.0001      0.0003            0.5086

 

PD x E                         11        0.0520          0.0904     0.0021     0.0608       <0.0001       0.0826       0.0291      0.1306            0.3856

 

 

 

Table 11. Influence of planting date and entry on yield and head traits for twelve genotypes of processing cabbage planted on May 15 and July 6, 2000 at the OSU Vegetable Crops Research Branch in Fremont, OH.

 

 

---------------------- head ---------------------          ------------------- core ------------------

-- yield (ton/A) ---        weight     density           -- diameter (cm.) --      length   base width            % of

Planting Date                N         marketable       total        (kg)       (g/cm3)          polar       equatorial       ------- (cm.) -------            head volume

 

 

May 15, 2000              48          37.0 a            38.0 a  2.80 a    1.08 a           17.5 a        18.9 a        7.7 a          3.6 a            1.1 a

 

July 6, 2000                 48          29.9 b            34.8 b  2.55 b    0.99 b           16.6 b        18.8 a        7.1 b          3.2 b            0.9 a

 

L.S.D.(0.10)                        2.43               2.41   0.13       0.02                0.26           0.43         0.43            0.17            0.54