Rao, P.B.Joshi, Bhawana2020-01-032020-01-032007-07http://krishikosh.egranth.ac.in/handle/1/5810139297The term Allelopathy denotes that body of scientific knowledge which concerns the production of specific biomolecules by one plant, mostly secondary metabolites, that can induce sufferenig in, or give benefit to another plant. This concept suggests that allelochemicals produced by a plant escape into environment and subsequently influence the growth and development of other neighbouring plants. Weeds are the plants which grow where they are not wanted and interfere with germination, growth, productivity and yield of cultivated crops in addition compete with crop plants for nutrients, light and moisture. In the present study, the allelopathic effect of four dominant weed species i.e., Ageratum conyzoides (L.), Chenopodium album (L.), Cynodon dactylon (L.) Pers. and Parthenium hysterophorus (L.) and three varieties of paddy straw, namely Basmati 386, Dubraj, Kalanamak on seed germination, seedling growth (length and dry weight), chlorophyll, proline and total protein contents in PBW-154, PBW-343, PBW-373, PBW-443, PBW-502, RR-21, UP-262, UP-1109, UP-2382 and UP-2425 varieties of wheat (Triticum aestivum L.) and to identify resistant and susceptibility to different weed species. The weed extracts showed both inhibitory as well as stimulatory influence on different parameters (seed germination, seedling growth both in terms of length and dry weight, chlorophyll, proline and total protein contents) in different varieties of wheat. The variety UP-262 was resistant and PBW-502 was susceptible on the basis of per cent reduction in seed germination. Similarly, the variety UP-2382 and PBW-343 in radicle length; UP-1109 and PBW-154 in plumule length; PBW-443 and UP-2425 in radicle dry weight; UP-2382 and PBW-373 in plumule dry weight; and PBW-154 and UP-2425 in total seedling dry weight were resistant and susceptible, respectively. On the basis of the chlorophyll contents (mg/g fresh weight) in different varieties, PBW-343 with C. dactylon (1.97) and UP-2382 with P. hysterophorus (97.16) in Chl-a content; PBW-502 with Kalanamak (4.88) and PBW-502 with P. hysterophorus (92.37) in Chl-b content; UP-2425 with Basmati 386 (0.80) and UP-2382 with P. hysterophorus (92.18) in total Chl (a+b) content and RR-21 with C. dactylon (5.20) was and PBW-154 with P. hysterophorus in chlorophyll ratio (a : b) were resistant and susceptible respectively.. On the basis of proline content (μ mol proline g-1 fresh weight) in different varieties, PBW-373 with C. dactylon (11.18) was resistant and UP-262 with Kalanamak (97.14) was susceptible. The total protein content in different varieties was increased, or remain same or decreased with different weed and paddy straw extracts as compared to control. The total protein content (mg/g fresh weight) was maximum in PBW-373 (7.9) with P. hysterophorus and minimum in UP-1109 with (2.4) with Dubraj. On the basis of total protein content in different varieties, UP-2382 with C. album was susceptible and PBW-502 with C. dactylon and UP-1109 with Basmati 386 were resistant. Thus, the above results indicated that the extract of P. hysterophorus showed maximum effect on all the varieties of wheat compared to others.ennullThesis