MSc

The experiment entitled “Evaluation of cabbage (Brassica oleracea L. var.
capitata) genotypes for head compactness and internal tipburn resistance under
rain shelter” was carried out in the department of Olericulture, College of
Horticulture, Vellanikkara during the period from May to September 2015. The
major objectives of the study were to identify compact genotypes with high yield
for rain shelter cultivation, to identify genotypes with internal tip burn resistance,
a calcium related physiological disorder and also to study the effect of calcium
foliar application on the incidence of internal tip burn. Seven cabbage genotypes
were evaluated with three different calcium foliar treatments (0%, 0.5% and
1.5%).
All the cabbage genotypes showed significant difference with respect to
qualitative and quantitative characters studied. Number of wrapping leaves, head
length, head breadth, net head weight, head index, harvest index and head
compactness directly contributed towards yield. The minimum number of
wrapping leaves (8.60) was in genotype G 1 (NS 43) and the genotype G 8 (Saint)
recorded the minimum number of non-wrapping leaves (7.70) . The genotype G 1
(NS 43) recorded maximum plant spread (50.70 cm), head length (12.91cm), head
breadth (13.40 cm), net head weight (787.33 g) and gross head weight (1136.66
g). The genotype G 4 (F 1 Border 777) recorded the maximum head index (1.31),
but harvest index was maximum for the genotype G 8 (69.60 %). All the genotypes
formed very compact heads in all Ca foliar treatments, except G 1 (NS 43) which
formed loose heads in C 2 (Ca 1.5 %) treatment, medium compact heads in control
(C 0 ) and C 1 (0.5 %) treatments. All the genotypes produced conical heads except
G 1 (NS 43) which produced round heads. The genotype G 5 (Green Voyager)
recorded maximum yield of 6.40 kg per plot. Among the seven genotypes, only
the genotype G 1 (NS 43) recorded slight tipburn incidence (4.16 %). Genotypes
G 3 (Super Ball 50), G 4 (F 1 Border 777), G 6 (Mahy 118) and G 8 (Saint) were free
from pest incidence and genotypes G 2 (Green Challenger), G 5 (Green Voyager)
and G 6 (Mahy 118) were free from disease incidence.Effect of different levels of calcium foliar application and the interaction
effect were non-significant in most of the characters. However the interaction G 4
C 0 recorded the lowest stalk length (5.25 cm) and interaction G 1 C 2 recorded the
highest gross head weight (1365 g). The interaction G 1 C 2 recorded slight
incidence of tipburn (1.78 %). There was no pest incidence in the interactions G 8
C 0, G 6 C 1, G 4 C 0 and G 3 C 1. The interactions G 5 C 0, G 2 C 0 and G 6 C 2 registered no
disease incidence.
Soil samples were collected from all the experimental plots before and
after raising the crop. Soil samples were analysed for pH, organic carbon,
available P, K, Ca, Mg, Fe and Mn content. There was no significant difference
with respect to soil pH, organic carbon, available P, K, Ca, Mg, Fe and Mn
content among the plots before and after raising the crop. Index leaf (recently
matured wrapping leaf and head) samples were collected from internal tipburn
susceptible genotype G 1 (NS 43) and high yielding, resistant genotype G 5 (Green
Voyager). Plant samples were analysed for N, P, K, Ca, Mg, Fe and Mn content
both in leaf and head. Here also there was no significant difference among
genotypes for N, P, K, Ca, Mg, Fe and Mn content both in leaf and head samples.
The foliar application of Ca increased leaf calcium concentration in both the
genotypes. Maximum leaf Ca content was recorded in the interaction G 5 C 2 (1.20
%) and it was lowest in G 1 C 2 (1.17 %).
The genotype G 5 (Green Voyager) produced very compact heads, higher
net head weight (1005.83 g), yield per plot (6.40 kg) and high benefit-cost ratio
(1.52). It was also resistance to internal tipburn. Hence this genotype can be
recommended for off-season cultivation under rain shelter in the central plains of
Kerala. From the present study it was found that internal tipburn incidence in
cabbage is genotype specific and it can be reduced by Ca foliar application. Only
the genotype G 1 (NS 43) was susceptible to internal tipburn among the seven
genotypes. Hence more number of genotypes are to be screened in further
experiments.