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Assam Agricultural University, Jorhat

Assam Agricultural University is the first institution of its kind in the whole of North-Eastern Region of India. The main goal of this institution is to produce globally competitive human resources in farm sectorand to carry out research in both conventional and frontier areas for production optimization as well as to disseminate the generated technologies as public good for benefitting the food growers/produces and traders involved in the sector while emphasizing on sustainability, equity and overall food security at household level. Genesis of AAU - The embryo of the agricultural research in the state of Assam was formed as early as 1897 with the establishment of the Upper Shillong Experimental Farm (now in Meghalaya) just after about a decade of creation of the agricultural department in 1882. However, the seeds of agricultural research in today’s Assam were sown in the dawn of the twentieth century with the establishment of two Rice Experimental Stations, one at Karimganj in Barak valley in 1913 and the other at Titabor in Brahmaputra valley in 1923. Subsequent to these research stations, a number of research stations were established to conduct research on important crops, more specifically, jute, pulses, oilseeds etc. The Assam Agricultural University was established on April 1, 1969 under The Assam Agricultural University Act, 1968’ with the mandate of imparting farm education, conduct research in agriculture and allied sciences and to effectively disseminate technologies so generated. Before establishment of the University, there were altogether 17 research schemes/projects in the state under the Department of Agriculture. By July 1973, all the research projects and 10 experimental farms were transferred by the Government of Assam to the AAU which already inherited the College of Agriculture and its farm at Barbheta, Jorhat and College of Veterinary Sciences at Khanapara, Guwahati. Subsequently, College of Community Science at Jorhat (1969), College of Fisheries at Raha (1988), Biswanath College of Agriculture at Biswanath Chariali (1988) and Lakhimpur College of Veterinary Science at Joyhing, North Lakhimpur (1988) were established. Presently, the University has three more colleges under its jurisdiction, viz., Sarat Chandra Singha College of Agriculture, Chapar, College of Horticulture, Nalbari & College of Sericulture, Titabar. Similarly, few more regional research stations at Shillongani, Diphu, Gossaigaon, Lakhimpur; and commodity research stations at Kahikuchi, Buralikson, Tinsukia, Kharua, Burnihat and Mandira were added to generate location and crop specific agricultural production packages.

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20191
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Subject: Entomology × Author: Bora, Madhumita Sonowal ×
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    ThesisItemOpen Access
    Diversity and foraging behaviour of syrphid flies on Brassica campestris L. and Mangifera indica L.
    (2019-07) Bora, Madhumita Sonowal; Deka, Mukul Kr.
    Investigation on the diversity and foraging behaviour of syrphid flies on Brassica campestris L. and Mangifera indica L. was carried out in the ICR Farm; Horticulture Orchard, Department of Horticulture and Apiculture laboratory, Department of Entomology, Assam Agricultural University, Jorhat during 2017-2018 and 2018-2019. The insects forager complex of rapeseed consisted of 27 species namely Apis cerana, A. dorsata, Nomia sp., Stomorhina discolour, Episyrphus balteatus, Betasyrphus aeneifrons, Syrphus sp., Eristalinus arvorum, E. polychromata, E. quinquestriatus, E. megacephalus, E. paria, Mesembrius quadrivittatus, Eristalis tenax, Phytomia errans, Melonstoma orientale, Asarkina ericetorum, Sphaerophoria sp., Dideopsis aegrota, Delias pasithoe, Micraspis discolor, Coccinella tranversalis, Chrysomya meghacephala, Musa domestica, Coccinella septempunctata, Syntomoides imaon and Pieris rapae. Out of these Stomorhina discolour was recorded to be maximum (9.37%). Whereas, in mango all total 15 species namely Apis cerana, A. dorsata, A. florea, Stomorhina discolour, Eristalinus arvorum, E. polychromata, E. quinquestriatus, E. megacephalus, E. paria, Mesembrius quadrivittatus, Asarkina ericetorum, Chrysomya meghacephala, Musa domestica, Neptis cartica and Oecophylla smargdina were recorded. Out of these Eristalinus arvorum was recorded to be maximum (12.05%). The highest species diversity index of 2.59 was recorded from rapeseed crop as compared to 2.03 from mango crop. The maximum total body length in Eristalinus arvorum (10.00 ± 0.52 mm) which was followed by E. polychromata (8.64 ± 0.51mm) and minimum Mesembrius quadrivittatus (2.19 ± 0.60 mm), respectively. The principal component analysis of 15 morphometric characters obtained from15 species of syrphids which explained 84.84 per cent variation among the species of syrphids. Whereas, in the principal component 1, 15 morphometric characters were influencing parameters with components loading from 0.985 to 0.280 that accounting for 76.32 per cent of the variation observed. The length and width of eggs of E. balteatus, B. aeneifrons and Syrphus sp. were 0.70 ± 0.01 mm and 0.26 ± 0.00 mm; 0.70 ± 0.01mm and 0.26 ± 0.00 mm; 0.71 ± 0.01 mm and 0.27 ± 0.00 mm, respectively. The incubation periods were 3.20 ± 0.45, 2.80 ± 0.45 and 3.40 ± 0.55 days, respectively. The maximum hatching percentage of eggs was 89.30 per cent of E. balteatus. The larvae passed through three instars. The maximum length and width of first instar larvae were 2.14 ± 0.03 mm and 0.70 ± 0.02 mm of E. balteatus followed by second instar larvae were 4.86 ± 0.05 mm and 0.90 ± 0.05 mm of Syrphus sp., respectively. The minimum duration of first instar larvae of B. aeneifrons was recorded (2.40 ± 0.55 days) followed by second instar larvae of B. aeneifrons and Syrphus sp. were recorded (3.40 ± 0.55 days), respectively. The total life period of male and female of E. balteatus were (37.60 ± 1.52 days and 38.60 ± 1.52 days) recorded. The number of Eristalinus and Syrphini per sq. m per minute on rapeseed was recorded to be maximum (7.89 ± 0.09 and 7.90 ± 0.93) at 1100-1200 and minimum (1.26 ± 0.07 and 1.53 ± 0.18) at 0700-0800 hours of the day. Maximum time spent per flower by Eristalinus and Syrphini also recorded to be 29.04 ± 2.03 seconds and 7.18 ± 0.18 seconds at 0700-0800 hours and minimum was 19.24 ± 3.09 and 5.03 ± 0.05 seconds at 1000-1100 hours of the day. The number of flower visit per minute was recorded to be maximum (3.90 ± 0.22 and 7.82 ± 0.32) at 1000-1100 hours and minimum (2.59 ± 0.21 and 2.95 ± 0.24) at 0700-0800 hours of the day. The number of Eristalinus and Syrphini per sq.m per minute on mango was recorded to maximum (8.04 ± 0.14 and 6.84 ± 0.13) at 1100-1200 and minimum (1.45 ± 0.07 and1.38 ± 0.10) at 0700-0800 hours of the day. Maximum time spent per flower by Eristalinus and Syrphini also recorded to be 26.85 ± 0.92 and 7.45 ± 0.14 seconds at 0700-0800 hours and minimum was 20.76 ± 1.49 and 5.52± 0.09 at 1000-1100 and 1200-1300 hours of the day. The number of flower visit per minute was recorded to be maximum (3.68 ± 0.11 and 6.53 ± 0.10) at 1300-1400 and 1100-1200 hours and minimum (2.54± 0.24 and 2.74± 0.05) at 1500-1600 and 1400-1500 hours of the day. Various meteorological parameters affected the different foraging activities of Eristalinus and Syrphini viz., number of Eristalinus/Syrphini per sq.m per minute, number of flower visit per minute and time spent per flower per second. Temperature and bright sunshine hours showed positive correlation whereas rainfall and relative humidity showed negative correlation with the different foraging activities of Eristalinus and Syrphini. The relative abundance of Eristalinus and Syrphini was recorded to be maximum (9.52 ± 0.69 nos. /5min) at 1100-1200 hours and (7.41 ± 0.38 nos. /5min) at 1200-1300 hours and minimum (1.66 ± 0.33 and 1.98 ± 0.11 nos. /5min) at 0700-0800 hours of the day. The number of loose pollen grain adhering to the bodies of Eristalinus and Syrphini was recorded to be 1333.2 ± 50.48 nos. and 1294.6 ± 65.10 nos. per forager. The maximum pollination index of 7.40 was recorded from Eristalinus as compared to 7.21 of Syrphini on rapeseed. The relative abundance of Eristalinus and Syrphini was recorded to be maximum (8.90 ± 0.22 nos. /5min) at 1100-1200 hours and (7.07 ± 0.51 nos. /5min) at 1200-1300 hours and minimum (2.40 ± 0.17 and 2.49 ± 0.09 nos. /5min) at 0700-0800 hours of the day. The number of loose pollen grain adhering to the bodies of Eristalinus and Syrphini was recorded to be 1415.80 ± 110.80 nos. and 1294.80 ± 60.82 nos. per forager. The maximum pollination index of 9.63 was recorded from Eristalinus as compared to 7.14 of Syrphini on mango.