B S TomarVISHWANATH ROHIDAS YALAMALLE2019-06-042019-06-042018http://krishikosh.egranth.ac.in/handle/1/5810106706t-10001The present investigation entitled “Studies on application of polymer, spermine and scape regulation on seed yield and quality in onion (Allium cepa L.) and garlic (Allium sativum L) was conducted at Seed Production Unit during rabi 2015-16 and 2016-17 with the objectives to study the effect of application of polymers, plant protectants, spermine and scape regulation on growth, disease intensity, thrips incidence, seed yield and seed quality. Onion mother bulb coating with polymer and 0.15 % fipronil + 0.25 % (carbendazim + mancozeb ) showed significantly higher values for seed yield attributes viz, productive scapes plant-1 (5.56), umbel diameter (6.97cm), 1000 seed weight (3.44 g), seed yield plant-1 (21.15 g), seed quality attributes-seedling length (10.18 cm), seed vigour index-I (923.42), seed vigour index-II (1752.10), lowest scape lodging (21.16%), EC (188.38 µmhos/cm/g), percent disease index (34.96) and thrips plant-1 (5.35). The residue of fipronil and carbendazim after 30 DAP in polymer coated bulbs were 2.04 ppm and 0.60 ppm where as pesticides applied as water soaking was 0.36 ppm and 0.05 ppm respectively.In garlic seed crop the application of polymer along with 0.25 % (carbendazim + mancozeb ) gave highest clove sprouting. Polymer coating and 0.15 % fipronil + 0.25 % (carbendazim + mancozeb ) showed significantly higher values for characteristics viz. bulb diameter, (4.43 cm), lower percent disease incidence (27.95) and No. of thrips plant-1 (1.17), whereas polymer coating along with 0.15 % fipronil had highest cloves bulb-1 (22.74) and yield plant-1 (17.48 g). Per-harvest spray of 1.00mM spermine recorded highest seed quality when germinated under favorable conditions. Plants sprayed with (0.25mM) spermine recorded lowest deterioration due to accelerated ageing, highest germination (70.33 %), seedling length (9.52 cm), seedling dry weight (16.03 mg), seed vigour index-I (666.36), seed vigour index-II (1114.77), SOD (0.032 unit/min/g of seed), POD (0.117 ∆/min/g of seed). After one year of ambient storage plants sprayed with 1.00 mM per-harvest recorded highest seed viability and vigor. Seed priming with 1.25 mM spermine recorded significantly higher seed quality attributes over unprimed seeds, but were at par with halo-priming. Seeds priming with 1.25mM spermine had minimal deterioration effects of accelerated ageing and recorded the highest seed quality attributes viz. germination (59.33 %), speed of germination (1.54), seedling length (9.10 cm),seedling dry weight (20.10 mg), seed vigour index-I (541.03), seed 103 vigour index-II (1072.47), SOD (0.11 unit/min/g of seed) and POD (0.03 ∆/min/g of seed). Scape regulation showed significant influence on seed quality. The scape length and umbel diameter were significantly higher in plants retained up to three scapes plant-1 . Highest number of florets umbel-1 (727.75), seeds umbel-1 (1464.62) was recorded in plants with one scape plant-1 . Plants with single scape produced 88.78 % more seed yield umbel-1 in comparison to plants with six scapes plant-1 . Seed quality parameters like 1000 seed weight, speed of germination and seed vigour was higher in plants up to four scape plant-1 . Key words: Allium cepa L., Allium sativum L., polymer, disease, thrips, spermine, scape regulation.en-USnullThesis