Fifty diverse paddy genotypes were evaluated under low land submerged field condition at two different locations i.e. Hingalganje (North 24 Pgs, West Bengal) and Baruipur (South 24 Pgs, West Bengal) during the kharif seasons for three consecutive years of 2011, 2012 and 2013 for the study of association between yield and yield components under submerged condition where the water depth was more than 50 cm at least for two weeks at the vegetative stage of crop. On the basis of mean performances genotypes viz., Mahananda, Sabita, Nagalmuda, Lakshmikajal, Purnendu and Jaladhi II performed better for seed yield than the tolerant checks. High broad sense heritability along with high genetic gain over mean was also observed for plant height, grains/panicle, test weight, and seed yield. Fertile grains per panicle, panicle length and test weight (1000 seed weight) are consistently highly positively correlated with the seed yield. These yield attributes were the major contributing traits for seed yield in rice under submergence in the set of genotypes under study.

For rainfed low land paddy ecosystems which is supposed to withstand the sudden rise of water level for short period of time i.e. up to two weeks has been considered as the submergence tolerant. Proper screening and evaluation method are very important for cost effective and economic breeding procedures that will benefits the farmers. The agro morphological characters which are responsible for submergence tolerance; character association and path coefficient analysis will be very much useful to select them for further assessment. Hybrid rice will be another approach which could mitigate the flash flood constraints. Proper understanding of anatomical characters such as aerenchyma formation and changes of diameter of aerenchyma of root, shoot and leaf will be very much important for submergence tolerance if it is linked with genetic factors. Biochemical manipulation of different plant hormone such as gibberellic acid, abscisic acid and ethylene; enzyme like alcohol dehydrogenase synthesis; chlorophyll content and non structural carbohydrate content of shoot has significant role for enhancement of survival during underwater growth. Plant extracts or herbal crude product in the form of dry and wet treatments along with proper growth nutrients will be a holistic approach for sustainable and integrated agriculture and will be a tool for crop improvement in future breeding programme for submergence tolerance in rice.

Aim:The incorporation of sub 1 gene in high yielding rice mega genotypes indicate that higher amount of Adh enzyme synthesis is controlled by the genetic factors. Adh enzyme will be the one of the vital factor for underwater respiration process of survival. Hence, rice genotypes with high amount of alcohol dehydrogenase enzyme synthesis during anoxic condition in compare with tolerant checks could be good promise for early introduction to the submergence prone area.Methodology: Fresh and disease free seeds of fifty diverse rice genotypes including tolerant and susceptible checks were taken and germinated. 0.1 gm cut five days old rice seedlings of various submergence dose of day 1, 2, 3, 4 and 5 along with control were evaluated separately in three replications for Adh enzyme estimation by standard protocols with spectrophotometer. Results:The peak time of Adh enzyme synthesis was during 72 hours to 96 hour of submergence period. Among paddy genotypes Mahananda along with Sabita and Purnendu performed well in compare with tolerant check paddy genotypes. Conclusion:As it is controlled by genetic factors, so estimation of Adh enzyme activity under submerged stage could be the potent biochemical marker for the screening for paddy genotypes for seedling stage of crop growth during flash flooding condition.

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The weed flora associated with field crop of rice in Bhadrak district of Odisha, India is studied for a period of 2 years (June 2016 to May 2018) based on data obtained from field exploration and literature consultations. Data are collected using standard procedures. The weed association is comprised of 149 species related to 41 angiosperm families and one pteridophytic family. Angiosperms are distributed in 8 superorders and 19 orders. 36.5% of the species are recorded from the superorder Commelinids, 18.9% from Malvids, 14.9% from Lamids, 13.5% from Fabids and 10.1% from Companulids as per APG III classification. Order Poales (48), Gentianales and Asterales ( 14) each, Caryophyllales (13) and Fabales ( 11) accounts for about 67.6% of the species in the district. The predominant families are Poaceae and Cyperaceae. The dominant species are Ammannia baccifera, Alternanthera sessilis, Argemone mexicana, Croton sparsiflorus, Cyperus alopecuroides, Echinochloa crusgalli, Eleocharis dulcis, Fimbristylis miliacea, Hygrophila auriculata, Ludwigia hyssopifolia and Oryza rufipogon. Forty eight of the identified species are perennial and 101 annual species. The therophytes are represented by 45.6% of the life form spectrum. Habitat wise distribution analysis shows forbs share 88 species followed by grasses (29 species) and sedges (18 species) respectively. Of the reported species 37.6% are used for animal fodder, 29.5% for the treatment of various diseases and 7.4% for edible purposes. Considering the importance of weed flora in the rice fields, this research will hopefully improve the monitoring and management of weed flora in the study area and highlight their importance in maintaining ecosystem services which could be a valuable tool for its conservation, preservation and addition of the local biodiversity.