Genotypic Characterization and population dynamics of Bemisia tabaci (Gennadius) in vegetable crops in Chhattisgarh
| dc.contributor.advisor | Dr. Kailash Chander Sharma | |
| dc.contributor.author | Archita Das | |
| dc.contributor.other | T-11291 | |
| dc.date.accessioned | 2024-10-25T06:40:42Z | |
| dc.date.available | 2024-10-25T06:40:42Z | |
| dc.date.issued | 2023 | |
| dc.description.abstract | The Whitefly, Bemisia tabaci Gennadius (Family: Aleyrodidae, Order: Hemiptera) has been listed as one among the "100 of the World's Worst Invasive Alien Species" by the International Union for the Conservation of Nature and Natural Resources (IUCN). The whitefly is one of the most significant pests because it transmits more than 100 viruses and causes economic loss in more than 60 crops. India holds the second position globally in vegetable crop production. Unfortunately, vegetable yields are significantly impacted, with an average reduction of 40%, due to the presence of whiteflies and whitefly transmitted begomoviruses. These whiteflies pose a challenge in terms of differentiation through conventional taxonomy due to their morphological similarities within genetic groups and also due to cryptic nature. Therefore, the molecular based diagnostics have come in place to decode the cryptic species. To address this, a total of 79 B. tabaci samples were collected from vegetable crops across 9 districts in Chhattisgarh, covering the north, central, and south zones, using a handheld aspirator. DNA isolation was performed using a Qiagen kit, and PCR was carried out, followed by partial sequencing of the mitochondrial cytochrome oxidase I gene using universal primers. The DNA sequences were aligned using the ClustalW program in MEGA Software, and homology search was conducted using NCBI-BLAST to identify the genetic groups through the construction of a phylogenic tree. Among the crops studied, Tomato (T2) exhibited the highest number of genetic groups, while Okra (T4) had the lowest. The overall genetic distance is 0.10. The diversity of genetic groups increased as we moved towards the southern region of Chhattisgarh. Specifically, six genetic groups namely Asia I, Asia II-1, Asia II-5, Asia I-India, Asia II-8, and Asia IV were found in the southern region, whereas only three genetic groups (Asia I, Asia II-1, and Asia II-5) were observed in the northern and central areas. Notably, Asia I was the most widely distributed genetic group, accounting for 69.62% of the occurrences in Chhattisgarh. Furthermore, Asia IV, which was obtained from brinjal in the Kanker region, represents the first report of its kind in India. In the second experiment, a field trial was conducted at Baronda farm, NIBSM, focusing on observing the population dynamics of B. tabaci and its relationship with macroclimate and microclimate. The whitefly population was monitored on five randomly selected plants by inspecting three leaves (upper, middle, and lower) on each plant at seven-day intervals. The results showed that the highest population of whiteflies was found in brinjal, followed by chilli, tomato, and okra. The appearance of the pest was first observed at 21 DAS, and its peak population was recorded at 72 DAS, 79 DAS, 72 DAS, and 58 DAS for chilli, tomato, brinjal, and okra, respectively. The study revealed a positive correlation between whitefly population and relative humidity while a negative correlation with temperature. This study infers to make a pest calendar which ishelpful to adopt control measure in 70 time for different crops and also it will serve as a model for survey, surveillance and forecasting. Furthermore, the counts of all life stages of whitefly were performed on three strata of the plants, with three leaves observed from each stratum. The distribution pattern showed that eggs were predominantly found on upper leaves in chilli (2.823±1.055), tomato (0.553±0.360), and brinjal(0.292±0.189) crops, whereas they were more prevalent on lower leaves in okra (0.461±0.398). Nymphs were mainly distributed in the middle stratum in chilli (1.353±0.738), tomato (2.4±0.480) andokra (0.523±0.348) crops, whereas they were more abundant in the lower stratum for brinjal (3.184±0.799) crop. Adults, on the other hand, were primarily located on the upper leaves in all four crops, including chilli (2.823±1.055), tomato (2±0.437), brinjal (3.469±1.681), and okra (1.261±0.608). This study helps us to take specific strata wise management strategy or sampling for research purposes. | |
| dc.identifier.uri | https://krishikosh.egranth.ac.in/handle/1/5810215864 | |
| dc.language.iso | English | |
| dc.publisher | DIVISION OF ENTOMOLOGY ICAR- INDIAN AGRICULTURAL RESEARCH INSTITUTE NEW DELHI – 110012 | |
| dc.sub | Entomology | |
| dc.theme | Genotypic Characterization and population dynamics of Bemisia tabaci (Gennadius) in vegetable crops in Chhattisgarh | |
| dc.these.type | M.Sc | |
| dc.title | Genotypic Characterization and population dynamics of Bemisia tabaci (Gennadius) in vegetable crops in Chhattisgarh | |
| dc.type | Thesis |