BHARAT, NARENDER KRUCHIKA2020-09-172020-09-172020-09https://krishikosh.egranth.ac.in/handle/1/5810151445ABSTRACT The present investigations entitled “Studies on the effect of thermophysical seed treatments on plant growth and yield in bell pepper” were carried out at the Department of Seed Science and Technology, Dr YS Parmar University of Horticulture and Forestry, Nauni, Solan (HP) during 2019-2020. Three experiments were conducted using bell pepper cv. Solan Bharpur. Under first experiment, in vitro screening of thermophysical methods i.e., hot water treatment at four different temperature-duration combinations of 49, 50, 51 and 52°C for 30, 45 and 60 min., hot air treatment at four different temperature-duration combinations of 70, 72, 74 and 76°C for 24, 36, 48 and 60 h and microwave seed treatment at micro power level 900 W for exposure of 5, 10, 15, 20 and 30 s along with control (untreated seeds) were done. Based on the germination %, speed of germination, seedling length (cm), seedling dry weight (mg), seed vigour index-I (Length), seed vigour index-II (Mass) and seed mycoflora, the three best treatments among each categories i.e., hot water seed treatment (T1 : Hot water 49°C/45 min, T2: Hot water 49°C/60 min, T3 : Hot water 50°C/60 min), hot air seed treatment (T4 : Hot air 72°C/24 h, T5 : Hot air 72°C/36 h, T6 : Hot air 74°C/48 h) and microwave seed treatment (T7:Microwave 5 s, T8: Microwave 10 s, T9 : Microwave 15 s) along with T0 : control (untreated seed) were used for further evaluations under nursery and field conditions. In the second experiment under nursery conditions, total emergence % (85.16%), speed of germination (78.20) and minimum disease incidence i.e., damping off % (6.94 %) was recorded in Hot water seed treatment at 50°C/60 min (T3), maximum seedling height (11.40 cm) was recorded in Microwave seed treatment for 5 s (T7) and minimum incidence of viruses (4.44 %) was recorded in Hot air seed treatment at 74°C/48 h (T6). In the third experiment conducted in field, the uniform and healthy seedlings from each treatment were selected and transplanted in the field. The maximum values w.r.t. plant height (60.33 cm), days to first marketable picking (60.00), average fruit weight (53.01 g), no. of fruit per plant (19.48), fruit yield per plant (1032.71 g), fruit yield per plot (6.19 kg), fruit yield per ha (305.99 q), harvest duration (31.67) and minimum values w.r.t. disease incidence of diseases like anthracnose (1.85%), cercospora leaf spot (3.73 %) and phytophthora rot (3.69%) were recorded in Hot water seed treatment at 50°C/60 min (T3). The incidence of virus diseases was recorded lowest (1.84%) in Hot air seed treatment at 74°C/48 h (T6) in bell pepper cv. Solan Bharpur.EnglishThesis