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2017 - 20182
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Subject: Seed Science and Technology × End date: 2018 × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    EFFECT OF DIFFERENT STORAGE STRUCTURES ON SEED BORNE DISEASES OF MAIZE
    (AAU, Jorhat, 2018) Terangpi, Hunmili; Borah, P K
    Maize cultivation in the world is limited by diseases which cause grain loss of about 11% of the total production. Fungi are among the principal causes of deterioration and loss of maize grain. Fungi could cause damage to farmers maize during the storage if conditions are favourable for their development. A systematic study on effects of different storage structures on seed borne diseases of maize during storage with special reference to Assam, (Karbi Anglong) was conducted, because of the prevailing climatic conditions has been identified to cause a problem in storage of maize. Maize seeds of different varieties (white, yellow and red colour maize) locally cultivated were collected from different farmers of Karbi Anglong district and brought to the NSP (Crops) laboratory for further study. The seeds were stored in four different storage structures viz., metallic bin, gunny bag, HDPE bag and without storage structures as cobs with husk, cobs without husk and as seeds. Ten treatments comprising 4 storage structures replicated thrice and laid out in Completely Randomized Design (CRD). Data on germination, root and shoot length, colony count (Percent frequency) were collected at 3 months interval up to 270 days. It was observed that the percent frequency of pathogens were found to increase with increase in storage period. Five number of fungal pathogens were isolated and identified such as Aspergillus flavus, Aspergillus niger, Fusariumsp, Curvulariasp, Colletotrichum sp before storage and during storage. The pathogenicity test conducted revealed that the highest rotting of seeds was showed by Aspergillus flavus. The study also revealed that germination percentage and seedling vigour was maximum in seeds stored in metallic bins as compared to other storage structures. The present study therefore recommends that to store seeds in healthy state and to prolong the enhanced seed viability, seeds be stored in metallic bins.
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    ThesisItemOpen Access
    EFFECT OF DRYING TEMPERATURES ON SEED QUALITY OF GREENGRAM
    (AAU, Jorhat, 2017-07) Gautam, Girija; Borah, Abhijit
    Green gram(Vignaradiata) is one of the most important and most widely cultivated pulse crops in India. The knowledge of seed drying and storage mechanism of green gram crop is essential to minimize the loss and quality standards of the seed. The present study is a preliminary step for identification of storage potential of green gram variety Pratap. A laboratory experiment was carried out to evaluate the effect of drying temperatures on various seed quality parameters and evaluation of these quality parameters over subsequent storage period. The experiment was carried out in the Seed Technology and Research Laboratory of Assam Agricultural University. In the present study four different drying temperatures were used viz. 35°C, 40°C,45°C and 50°C and sun drying was taken as control. After a particular drying period (for each treatment different drying period), when it reaches the desired moisture content (8%, wet basis), the seeds were removed from the hot air oven and stored in HDPE (high density poly ethylene) interwoven bags.. Observations were taken at bimonthly interval and the final observations were taken at the nine months of storage. Based on the results it was found that drying at 50°C decreased the drying time by almost 50% compared to drying at 35°C but it was detrimental to embryo viability and germination. The highest germination, seed vigour index, seed viability and field emergence were found in the samples dried at 35°C which was at par with sun drying. The lowest pest incidence was observed in the samples dried at 50°C, whereas the highest pest incidence percentage was found in samples dried under sun and it was statistically different with all other treatments. However, with the increase in storage duration, the seed quality parameters were found to be decreased except pest infestation which was found to be increased. Although in most of the cases drying temperature 35°C was found at par with sun drying but due to unpredictability and inherent disadvantages along with resultant high pest infestation during storage it cannot be recommended. Thus, from the present study drying temperature of 35°C is recommended for drying and subsequent safe storage of green gram seeds.