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Bhendi yellow vein mosaic disease (BYVMD) is the most devastating viral disease of okra (Abelmoschus moschatus ssp. moschatus) which affects yield and quality of the produce in India. The causative agent of BYVMD is begomovirus i.e. bhendi yellow vein mosaic virus (BYVMV) having DNA-A molecule along with betasatellite. Present study was carried out during 2019–21 at research farm of ICAR-National Bureau of Plant Genetic Resources, New Delhi to find out the diversity of begomovirus and its satellite nucleotide sequences derived from wild okra infected samples exhibiting conspicuous symptom of BYVMD using PCR-based detection technique on two wild okra symptomatic samples, viz. EC361170 and EC361148. Full length amplification of BYVMV satellite molecule and partial amplification of DNA-A was carried out using PCR and cloning of both randomly selected samples showed the presence of monopartite BYVMV. In both samples, presence of DNA-A molecule, betasatellite and alphasatellite were noticed. Two year (kharif 2019 and 2021) field screening of 10 accessions of wild okra (Abelmoschus moschatus ssp. moschatus) was carried out at ICAR-NBPGR, New Delhi. Out of 10 accessions, viz. EC360586, EC360794, EC360830, EC360900, EC359730, EC359836, EC359870, EC360351, EC361111 and EC361171 screened, 4 accessions, viz. EC360794, EC360586, EC360830 and EC361171 showed resistant (R) reaction during both the seasons against BYVMD. This is the first study which showed the presence of alpha-satellite molecule of BYVMV from New Delhi region in wild okra along with its resistance source.

Okra enation leaf curl disease (OELCuD) is a recently emerged whitefly insect vector transmissible viral disease of okra which adversely affects the quality and quantity of okra fruits. Okra enation leaf curl virus (OELCuV) is a main disease causative agent. Two year (kharif 2018 and 2019) field experiments were conducted at research farm of ICAR-National Bureau of Plant Genetic Resources, Pusa, New Delhi for field screening of 10 wild okra (Abelmoschus moschatus ssp. moschatus) accessions, viz. EC360586, EC360794, EC360830, EC360900, EC359730, EC359836, EC359870, EC360351, EC361111 and EC361171. Out of 10 accessions, 4 accessions, viz. EC360794, EC360586, EC360830 and EC361171 showed resistance (R) reaction in both the seasons. Whitefly population was also monitored in both the rainy (kharif) season, since, OELCuD is transmitted by whitefly insect vector. Majority (>77%) of okra genotypes were moderately preferred by the whiteflies. To further validate the resistance reaction in these 4 field resistant accessions, artificial screening experiment was conducted using viruliferous whitefly vector and VRO 6 as susceptible check. Prominent okra enation leaf curl symptom appeared after a minimum incubation period of 15 days under controlled conditions. Betasatellite (DNA-β) molecule of OELCuV was amplified (1.3 kb) using PCR for virus detection and these 4 accessions were found free from virus. These 4 promising accessions would serve as resistance source in breeding programmes to develop varieties resistant to OELCuV.

Present study explored the effect of salinity stress on seedling mineral composition, chlorogenic acid and polyphenol oxidase content of the two genotypes (GT25 and GT26) of egg plant (Solanum melongena L.). Selected egg plant genotypes were exposed to salinity stress (25-150 mM NaCl) along with control. Plants were grown in the field of School of Biotechnology, Gautam Buddha University during 2018-19. Drastic impacts of salinity stress as preliminary symptom were seen on seed germination. Genotype GT25 and GT26 were proficient to germinate only up to 100 mM and 75 mM NaCl respectively under salinity treatment. Results showed very poor growth along with necrotic/ dead tissue in the germinated seedlings leaves after the 30 days salt treatment in GT26 in100 mM NaCl treatment. Accumulation of Na+ ions is comparatively lower (67%) in GT25 under 75 mM NaCl concentration. On the contrary mineral (Cu, Mn, K) content, enzymatic activity like chlorogenic acid and polyphenol were resulted higher in GT25 compared to GT26 when subjected to NaCl stress (75 mM). These results indicate that egg plant genotypes respond to salt induced oxidative stress by enzymatic defense systems. The accumulation of polyphenol and chlorogenic acid suggest a role in protective metabolites. Hence it can be concluded that the GT25 possess strong tolerance against salt stress and could be an important genotype resource for the salt tolerance breeding programme of egg plant.

In the study Indian mustard [Brassica juncea (L.) Czern. & Coss.] was treated with different doses (0, 2.5, 10, 20 and 100 Gy) of gamma rays (radioactive cobalt, 60Co) and the effects were investigated on callus initiation, seed germination, seedling growth, total chlorophyll, protein and proline contents of seedling leaves, which were grown from hypocotyl explant of non-irradiated and irradiated seeds. Experiment was conducted at School of Biotechnology, Gautam Buddha University during 2017–18. The results showed that irradiated seeds had increased seed germination per cent, seedling length, fresh and dry weight, total chlorophyll, protein and proline content in low dose exposure (2.5Gy). Callus cultures were established from hypocotyl explants of 15 days old seedlings obtained from irradiated and non-irradiated seeds of B. juncea on MS1 [MS+BAP (2 mg/ml) + 2,4 D (1 mg/ml)] and MS2 [MS+BAP (2 mg/ml) + 2,4 D (0.5 mg/ml)] medium. Cultured hypocotyls formed callus at their cut ends within a week and simultaneously differentiation started into nodular structures from their base. MS1 callus induction medium gave good callus induction percentage (58%) as compared to MS2. It was observed that the callus was green, compact and showed 83% induction frequency in 100Gy gamma dose in MS1, whereas in different dose treatment (2.5–20Gy), callus was white and friable. It turned light brown in 100Gy treatment in MS2 medium. Thus, results of the present study showed pre-sowing seed irradiation is an effective method of improving seed germination at the early developmental stage of the plant.

Okra enation leaf curl disease (OELCuD) caused by Okra enation leaf curl virus (OELCuV) is a whitefly (Bemisia tabaci) transmitted viral disease of okra which deteriorates vegetable quality and reduces yield. The OELCuV was confirmed based on the amplicon of 1.3 Kb of beta satellite (DNA-β) molecule of the virus. Field screening of wild okra (Abelmoschus moschatus ssp. moschatus) accessions was carried out for OELCuD resistance during kharif 2017-19 at experimental Farm of ICAR-National Bureau of Plant Genetic Resources, Pusa, New Delhi. Out of 76 wild okra accessions tested, 10 accessions, viz. EC360586, EC360794, EC360830, EC360900, EC359730, EC359836, EC359870, EC360351, EC361111 and EC361171 showed resistant (R) reaction in kharif 2017, whereas in kharif 2019, only four accessions, viz. EC360794, EC360586, EC360830 and EC361171 exhibited R reaction and remaining six accessions were moderately resistant (MR). In the first year, average percent disease index (PDI) was 14.15 and overall PDI ranged from 3.70 to 52.86. The range of PDI was 4.53-56.40 during the second year with an average PDI value 18.04. Apart from PDI determination, whitefly population was also monitored in both the years mainly showed moderate preference. The prominent four accessions of okra, viz. EC360794, EC360586, EC360830 and EC361171 could be utilized in resistance breeding programmes against OELCuV.

A total 76 germplasm accessions of wild okra (Abelmoschus moschatus ssp. moschatus) along with 4 checks were evaluated against okra leafhopper Amarasca biguttula biguttula Ishida in field condition during kharif 2017 and 2019. Of the 76 wild okra accessions used for two years of field screening, negligible preference of okra leafhopper insect exhibited towards nine wild okra accessions namely EC360586, EC360794, EC360830, EC360900, EC359730, EC359836, EC359870, EC360351 and EC361171 with hopper population in the range of 1.33 to 1.44/leaf while moderate preference of okra leafhopper was observed to another 11 wild okra accessions during first year of field screening (kharif 2017). During the second year (kharif 2019) of field screening, negligible preference of okra leafhopper was recorded on five accessions, viz. EC360586, EC360794, EC360830, EC360900 and EC361171 with hopper population in the range of 1.33 to 1.45/leaf while moderate preference response of okra leafhopper was observed on two wild okra accessions only. Whereas, high to very high preference response of okra leafhopper was observed on the remaining wild okra accessions during both the years of field screening and all were found susceptible. Based on two years field screening of wild okra accessions against okra leafhopper, five wild okra accessions, viz. EC360586, EC360794, EC360830, EC360900 and EC361171 were found resistant against okra leafhopper. The hopper burn symptoms were also negligible on these 5 accessions.

Okra yellow vein mosaic disease (OYVMD) is a major viral disease of okra crop caused by Okra yellow vein mosaic virus (OYVMV). The disease is responsible for direct yield loss in terms of both quantity and quality of capsules (fruits). Initially, DNA-A of coat protein, intergenic region and partial rep protein sequences were determined using OY2395F/OY680R specific primer and the amplified 1.2 Kb band product showed presence of OYVMV. Two years field screening of wild okra accessions (Abelmoschus moschatus ssp. moschatus) carried out during kharif 2017 and 2019 against OYVMD in agro-ecological conditions of New Delhi. Among seventy six (76) wild okra accessions 10 accessions, viz. EC360586, EC360794, EC360830, EC360900, EC359730, EC359836, EC359870, EC360351, EC361171 and EC361111 exhibited resistant (R) response in kharif 2017. While in 2019, out of these 10 promising accessions, four accessions, viz. EC360794, EC360586, EC360830 and EC361171 further showed R response. Rest of the tested lines showed either moderately resistant (MR) or susceptible (S) response. Average percent disease incidence (PDI) value was 19.51% and range value was 4.46 to 64.06% for the first year of field screening. Whereas the recorded average PDI were 21.77% with the range value of 4.36 to 67.33% in the second year. For both the years, out of 76 accessions, four accessions, viz. EC360794, EC360586, EC360830 and EC361171 were found promising and exhibited R response consistently. These promising lines could be utilized in breeding programmes for development of varieties resistant to OYVMV.