M Sc

Oriental pickling melon is a crop with cultural and economic significance in
Kerala. Vivipary has been observed in this crop which reduces the seed yield and
quality. Adjusting the planting time and application of some chemicals were found
effective in controlling vivipary.
The study on ‘Impact of potassium and ABA application on vivipary and seed
quality in oriental pickling melon (Cucumis melo var. conomon Mak.)’ was conducted
at the Department of Seed Science and Technology, College of Agriculture, Kerala
Agricultural University, Vellanikkara, Thrissur during the year 2019-2021 using the
variety ‘Saubhagya’ to understand the effect of different levels of potassium and ABA
on vivipary and the quality of seeds.
The crop was sown during the month of February (2021) following randomised
block design with eight treatments and three replications. The treatments consisted two
foliar sprays of potassium (0.5% MOP, 1% MOP, 1.5% MOP) at 50 per cent flowering
and at an interval of two weeks after flowering, one foliar spray of abscisic acid (100
mg/l ABA, 200 mg/l ABA and 300 mg/l ABA) at 50 per cent flowering and a basal
application of recommended fertilizers with 50 percent additional potassium (POP +
50% K). The treatments had significant impact on fruit and seed quality parameters.
The fruit length and yield were enhanced in the ABA treatments. The potassium
treatment, POP + 50% K also gave significantly higher fruit yield which was on par
with the ABA treatments. Higher content of potassium in fruit flesh and placenta was
observed in 300 mg/l ABA treatment.
The treatments were effective in controlling the vivipary. The abscisic acid
treatment (300 mg/l ABA) was the most effective which reduced the vivipary up to 1.37
per cent followed by the treatment with potassium (1.5 per cent MOP) where the
vivipary was 3.29 per cent. The number of seeds per fruit and the total seed yield was
the highest in the treatment with 300 mg/l abscisic acid.
The seeds extracted from fruits harvested from the field experiment were used
for the seed longevity studies. The storage potential was assessed with the help of
accelerated ageing test. The seeds were tested for different quality parameters after each
day of accelerated ageing and the results showed that the seed quality deteriorated
during the 7-days of ageing in all treatments. The seed quality parameters like vigour,
germination, shoot and root length decreased whereas the electrical conductivity of seed
leachate, mean germination time, seed moisture and seed infection per cent increased
indicating a decline in seed quality over accelerated ageing.
The highest germination and vigour throughout the accelerated ageing was observed
in seeds collected from treatment 100 mg/l ABA and it maintained minimum
germination for seed certification prescribed by IMSCS (60.00% for melon) till day 4
of accelerated ageing. The highest dry weight of seedling and lowest electrical
conductivity of seed leachate were observed in seeds extracted from treatment 300 mg/l
ABA.
The seed infection did not vary among the treatments. Initially there was no
incidence of any pathogens but as the ageing period advanced the seed infection per
cent increased. The pathogens like Aspergillus sp. and Pencillium sp. were identified.
The agar plate method showed higher infection per cent compared to blotter method.
From the study it can be concluded that the overall performance of the seed was
found to be higher in abscisic acid treatment (300 mg/l ABA) indicating that it is the
best treatment among all the treatments given.