Abstract: Disclosed are novel adenine derivatives represented by the formula I and agriculturally acceptable acid addition salts thereof represented by the formula: ##STR1## wherein n is an integer of 2-4. Compositions for increasing yield of crops such as leguminous crops and gramineous crops which contain the above adenine derivatives or salts thereof as an active ingredient and methods for increasing yield of crops using these compositions are also disclosed.

Abstract: Use of agriculturally acceptable salts of compounds of the following formula for promoting the growth of plants. ##STR1## wherein Hal represents a chlorine, bromine or iodine atom, X.sub.1 represents a hydrogen or chlorine atom, or a methyl, trifluoromethyl, nitro, methoxy or t-butyl group, and X.sub.2 represents a hydrogen atom, or both X.sub.1 and X.sub.2 represent a chlorine atom or a methyl group; and Y represents a hydrogen atom, or a C.sub.2-6 alkylcarbonyl, benzoyl, N-phenylcarbamoyl, N-3,4-dichlorophenylcarbamoyl, chloropropylcarbonyl, methoxycarbonyl, carbamoyl or methacryloyl group.

Abstract: A method of increasing the harvest of a crop which comprises applying an effective amount of taurine to the crop or its seeds, and a composition therefor.

Abstract: A plant growth regulating composition comprising as an active ingredient a combination of(a) at least one gibberellin-type plant hormone, and(b) at least one compound selected from compounds of the general formula ##STR1## wherein R represents a C.sub.1 -C.sub.5 alkyl, C.sub.2 -C.sub.5 alkenyl, C.sub.2 -C.sub.5 alkynyl, C.sub.1 -C.sub.5 haloalkyl or benzyl group,and agriculturally acceptable salts thereof.