Pollen suppressant comprising a 5-oxy- or amino-substituted cinnoline

A pollen suppressant of the formula ##STR14## wherein:

• X represents a group of the formula OR.sup.1 wherein R.sup.1 represents C.sub.1 -C.sub.4 alkyl substituted with 1 to 3 halogen atoms;
• Y is hydrogen, C.sub.1 -C.sub.22 linear alkyl or alkenyl containing up to four carbon-carbon double bonds, C.sub.3 -C.sub.6 branched alkyl or alkenyl, C.sub.1 -C.sub.4 alkoxyalkyl, cyclohexylmethyl, halogenated C.sub.1 -C.sub.4 alkyl, phenyl, benzyl, --(CH.sub.2 --CH.sub.2 O).sub.m CH.sub.2 CH.sub.3 in which m is an integer from 1 to 5, or --CH(CH.sub.2 OR.sup.4) CH.sub.2 OR.sup.5, or --CH.sub.2 CHOR.sup.4 CH.sub.2 OR.sup.5 in which either R.sup.4 or R.sup.5 but not both represent a C.sub.1 -C.sub.22 linear alkyl- or alkenylcarbonyl group containing up to four carbon-carbon double bonds and the remainder of R.sup.4 and R.sup.5 is H;
• and
• R represents phenyl, naphthyl or phenyl or naphthyl substituted with one to three substituents selected from the group consisting of halogen, trihalomethyl, --CONH.sub.2, C.sub.1 -C.sub.4 alkoxy, C.sub.1 -C.sub.4 alkyl and cyano;
• or an agronomically acceptable salt thereof.

A method of inducing male sterility in a gramineous plant, which comprises treating said plant, a seed from which said plant is to be grown, or a medium in which said plant is growing or is to be grown with a compound of the formula ##STR15## wherein X represents a group of the formula OR.sup.1 wherein R.sup.1 represents C.sub.1 -C.sub.4 alkyl substituted with 1 to 3 halogen atoms;

• Y is hydrogen, C.sub.1 -C.sub.22 linear alkyl or alkenyl containing up to four carbon-carbon double bonds, C.sub.3 -C.sub.6 branched alkyl or alkenyl, C.sub.1 -C.sub.4 alkoxyalkyl, cyclohexylmethyl, halogenated C.sub.1 -C.sub.4 alkyl, phenyl, benzyl, --(CH.sub.2 CH.sub.2 O).sub.m CH.sub.2 CH.sub.3 in which m is an integer from 1 to 5, or --CH(CH.sub.2 OR.sup.4)CH.sub.2 OR.sup.5 or --CH.sub.2 CHOR.sup.4 CH.sub.2 OR.sup.5 in which either R.sup.4 or R.sup.5 but not both represent C.sub.1 -C.sub.22 linear alkyl-or alkenylcarbonyl group containing up to four carbon-carbon double bonds and the remainder of R.sup.4 and R.sup.5 is H;
• and
• R represents phenyl, naphthyl or phenyl or naphthyl substituted with one to three substituents selected from the group consisting of halogen, trihalomethyl, --CONH.sub.2, C.sub.1 -C.sub.4 alkoxy, C.sub.1 -C.sub.4 alkyl and cyano;
• or an agronomically acceptable salt thereof.