EFFECT OF GAMMA RADIATION ON THE GROWTH, YIELD AND QUALITY OF FOUR ONION ACCESSIONS

Abstract

An experiment was conducted at the Horticulture farm of Hajee Mohammad Danesh Science and Technology University and the Laboratory of Bangladesh Institute of Nuclear Agriculture (BINA), Mymensingh during the period from November, 2017 to May, 2018 to study the effects of gamma radiation on the growth, yield and quality of four onion accessions. The experiment was consisted of two factors such as (i) different accessions viz., accession-1, accession-2, accession-3, accession-4 and (ii) four gamma radiation levels (0 Gy, 50 Gy, 75 Gy and 100 Gy). Seeds from all accessions were irradiated separately with 50 Gy, 75Gy, 100 Gy and also a control at BINA from 60Co gamma radiation sources. The experiment was laid out in RCBD with three replications. The seeds of 16 treatment combinations of the accessions and radiation levels were sown in seed bed on 15th November, 2017 and 45 days old seedlings were transplanted in the main field on 30th December, 2018. Some biochemical compositions were also tested after harvest on 26th March, 2018. Different accessions showed significantly influenced on almost all the mentioned parameters studied concerned with growth, yield contributing characteristics, yield as well as biochemical characteristics. The accession-3 produced the highest germination (67.25%) and bulb yield (16.57 t/ha) with increased plant height (49.00 cm), number of leaves per plant (7.08), fresh weight of leaves, individual bulb weight, diameter of bulb, length of bulb, chlorophyll (7.23 µmol/m2 ) content of leaf, TSS (14.83%), calcium (0.16%), phosphorus (0.37%), protein (12.60%), and vitamin C (9.18 mg/100g) content of bulb compare to other accessions. Radiation levels also had significant influence on all the parameter studied. The application of the 75 Gy gamma radiation produced highest germination (79.33%), plant height, number of leaves per plant, bulb diameter, individual bulb weight, length of bulb, chlorophyll content (7.45 µmol/m2 ) of leaf, TSS (15.92%), calcium (0.16%), phosphorus (0.40%), vitamin C (9.22 mg/100g), protein (11.20%) and bulb yield (17.47 t/ha) as compared to control. The combined effect of accessions and gamma radiations was statistically significant on the yield, yield contributing characters as well as quality of onion. The highest germination (82.33%) as well as plant height, no. of leaves per plant , individual bulb weight, diameter of bulb, length of bulb, bulb yield (18.59 t/ha), chlorophyll content in leaf, calcium, phosphorus, TSS, vitamin C and protein content in bulb were recorded from accession-3 radiated with 75 Gy. Similarly the lowest bulb yield (14.45 t/ha) as well as in respect of almost all the mentioned parameters were found at accession-1 with control treatment. Therefore, the overall results indicate that accession-3 with 75 Gy might be an efficient and eligible practice for onion production.