PhD

Two field experiments were conducted at the Instructional Farm,
College of Agriculture, Vellayani, Thiruvananthapuram, to study the effect of varying
levels of nitrogen (n), ethephon (g) and drip irrigation frequency (i) on the
productivity of snakegourd. The influence of the treatments on the size, quality and
shelf life of the produce and also on the physico-chemical properties of soil was
investigated. The trials were conducted during the summer seasons (December
to April) of 1994-'95 and 1995-'96.
The experiments were laid out in 4 2x2 + 2 asymmetrical confounded
factorial design with two replications and each replication included two blocks.
Combinations of four levels each of N (35, 70, 105 and 140 kg ha'), ethephon (0, 50,
100 and 200 ppm) and two frequencies of drip irrigation (5 mm CPE and 10 mm CPE)
constituted the treatments along with two controls (nogoiI and llogoi2) in each block.
The highest order interaction NOI was confounded in both the replications.
Results of the field experiments revealed that during both the years of
experimentation, nitrogen, ethephon and irrigation frequency exerted significant
positive influence on the fruit yield of snakegourd. During both the years, the higher




levels of nitrogen (105 and 140 kg N ha') were found to be significantly superior to
the lower levels (70 and 35 kg N ha'). Pooled analysis of the yield data also
revealed a similar trend. Growth characters like internodal length, number of leaves
plant" and dry matter production showed significant enhancement due to N
application. The positive significant effect of N was manifested in the yield attributes
viz., number of fruits plant" and average fruit weight. Significant increase in the
WUE of the crop due to N application was also observed. The content and uptake of
major nutrients also increased substantially due to applied N. Nitrogen improved the
quality of fruits, significantly, in terms of crude protein, total sugars, reducing sugars
and ascorbic acid content. However, the shelf life was adversely affected by it. The
highest net profit and B:C ratio were recorded by 105 kg N ha' (Rs. 74,636/- and
2.37, respectively) compared to the other levels of N. Considerable improvement in
the physico-chemical properties of soil due to applied N was also noticed.
The results of the field experiments also indicated significant yield
. increase in snakegourd due to ethephon application. The higher levels of ethephon ie.,
100 and 200 ppm, were found to be significantly superior to the lower levels in this
regard. Growth and yield attributes as well as quality of fruits were favourably
influenced by ethephon. Through its indirect positive effect on fruit yield, the higher
levels of ethephon improved the WUE of the crop significantly over its lower levels.
The economic analysis also revealed the positive effect of ethephon on the net profit
and B:C ratio and the highest values were registered by 200 ppm ethephon
(Rs. 71,194/- and 2.31, respectively).





With respect to irrigation frequency, il (irrigation at 5 mm CPE)
registered significantly higher fruit yield compared to i2 (irrigation at 10 mm CPE):
Growth characters and also the quality of fruits exhibited a similar trend. More
frequent irrigation treatment (i.) exerted its positive significant effect on yield
attributes viz., number of fruits plant:' and mean weight and girth of fruits. The
physical optima for N at il were worked out to be 100 and 115 kg ha" during the first
and second year, respectively. Economic analysis also revealed the favourable effect
of frequent drip irrigation, with il registering substantially higher net profit and B:C
ratio (Rs. 70,038/- and 2.28, respectively) compared to i2 (Rs. 61,615/- and 2.14,
respecti vel y) ..
A perusal of the data on fruit yield and economics of the treatment
combinations elicited the favourable effect of n3g4il which registered the highest fruit
yield, net profit and RC ratio (31.06 t ha", Rs. 1,04,271/- and 3.04, respectively) and
hence this combination could be adjudged as the best one for snakegourd cultivation.