Variance components and correlations of agronomic traits among cabbage (Brassica oleracea var. capitata L.) maturity groups

In this paper we studied the variability and correlation of cabbage traits in different maturity groups. The study included early spring cabbages (planted in early spring, harvested in early summer) and autumn cabbages (planted in mid-summer, harvested in late autumn). Using coefficients of variation and correlation coefficients, we analyzed 17 cabbage traits in 35 commercially grown cultivars, F1 hybrids, and experimental F1 hybrids. The traits were analyzed separately for each maturity group. In the early cabbages, the coefficients of variation ranged from 4.8 to 44.2%. The calculated correlation coefficients differed between the two maturity groups. The early cabbages had 26 significant positive correlations. The positive correlations calculated among different traits of early cabbages defined this group fully and made it distinct from the late-maturing genotypes. Plant height and rosette diameter in the early genotypes were highly positively correlated with rosette weight, whole plant weight, head weight, usable portion of head, head height, and head diameter. Plant height and rosette diameter participate in the formation of active photosynthetic area in early cabbages. Rosette width in these genotypes provides a greater influx of light and heat, which results in greater head weight. Also, in early cabbages that have greater plant height, the leaf rosette will not lie on the cold surface of the ground in the spring. The activity of the cabbage plant is thus more focused towards the formation of larger head weight. Head volume in the late genotypes was highly positively correlated with rosette diameter, whole plant weight, head weight, usable portion of head, inner stem length, and head height. In late cabbages plant activity is directed towards the formation of head volume due to the longer duration of the growth period, larger leaves, and differences in climatic conditions.