Synthesis and evaluation of oxanilates and oxamates as chemical hybridizing agents for wheat (Triticum aestivum L).

Induction of male sterility by the deployment of chemical hybridizing agents (CHAs) holds immense potential in heterosis breeding of wheat using “two-line’’ approach. Various derivatives of oxamic and oxanilic acids including their ethyl esters were prepared by synthesis and they along with their potassium salts were evaluated on wheat varieties HD 2285 and HD 2733. The field experiments were randomized with two test concentrations (1000 & 1500 ppm) with three replicates for both genotypes. The test chemicals were sprayed at premeiotic stage as oil in water emulsion or aqueous solution as the case might be. CH 9832 (800 ppm) was used as reference CHA. Ten spikes per replicate were bagged after spike emergence before anthesis. Five of them were dusted with pollens of HDR 77 after two days. Observations were made on pollen spikelet sterility using standard procedures. The numbers of seeds per spikelet and per spike were counted by picking five bagged and unbagged spikes each. The results of induction of spikelet sterility on two genotypes of wheat have shown that ethyl oxamates were superior to ethyl oxanilates. The potassium salts were superior to their acids, which in turn were better than their ethyl esters. Potassium salts of 4’-fluoro and 4’-bromo oxanilic acids gave the best results with mean per cent induction of sterility of 70.3 and 58.6. Structure activity relationship analysis revealed that heteroaromatic ring was no better than the aryl ring in imparting induction of male sterility.