In the absence of viable alternative technology of hybrid wheat development, chemical induction of
male sterility mediated technology based on chemical hybridizing agents (CHAs) holds a great potential. N-Acylaniline derivatives, namely, ethyl 4'-fluoro oxanilate (1) and ethyl 4'-trifluoromethyl oxanilate (2) containing
halogen atoms in the para position of the aryl ring and substituted
amide linkage (-CO-NH-) in the acyl side chain induced >98% spikelet
sterility on three genotypes of wheat, namely, PBW 343, HD 2046 and HD 2733, at 1500 ppm. The active moieties were incorporated in the form of
herbicide-CHA chimera and
amino acid analogues using
glycine and
alanine as templates. The target activity was made more selective by synthesizing chimeric structure of
herbicide (
2,4-dichlorophenoxyacetic acid and
dalapon) and the most active CHA templates, namely, 4- fluoroanilinyl and beta-ethoxycarbonyl moieties. Among
herbicide-CHA chimera ethyl 2',4'-dichlorophenyl
oxalate (14) induced 79.11%
male sterility, whereas benzyl methyl 2-oxo-3-azaadipate (20) was the best, inducing 73.87%
male sterility in HD 2733, among
amino acid analogues. The CHAs were found to modify the reproductive biology to ensure cross-pollination in the cleistogamous wheat flowers, increasing the probability for the development of hybrids.