Relative effect of different chemicals and out-pollination promoting techniques for increasing hybrid seed yields in rice (Oryza sativa L.)

Relative effect of different chemicals viz. GA₃ NAA, Boric acid, Zinc sulphate, Potassium di-hydrogen phosphate, Urea and Shima rock coupled with leaf clipping & supplementary pollination was evaluated on panicle exsertion, seed set and seed yields in IR58025A/IR58025B multiplication plot planted in a fixed row ratio of 2B:6A. Among different chemicals evaluated, only GA, was found effective in overcoming the problem of poor panicle exsertlon in CMS line. Moderate dose of GA₃ in combination with effective supplementary pollination was found to have significant positive effect on seed set and seed yield. As compared to kharif, rabi season is found more favorable to obtain high seed yields. Correlation study indicated that seed yields significantly depend on percentage seed set and not on percentage panicle exsertion. Further, as compared to GA₃ application, supplementary pollination was found more effective in increasing seed set and consequently the seed yield. This warrants the need to capitalize first on out-pollination promoting techniques with a special emphasis on supplementary pollination, rather than increasing panicle exsertlon through the use of GA₃ or any other such chemical, to enhance seed yields in hybrid seed production field.