Impact of potassium and ABA application on vivipary and seed quality in oriental pickling melon (Cucumis melo var. conomon Mak.)

Abstract

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.