Induced pleiotropy for curv~d stigma and genetic male sterility in tetraploid cotton (Gossypium hirsutum L.)

Abstract

Cytoplasmic genic male sterility (CGMS) has been developed with the cytoplasm of Gossypium harkanessii and the genome of G. hirsutum and a single dominant restorer gene from G. harkanessii to restore fertility [1-3]. The double recessive genetic male sterility with msSmsSms6ms6 alleles is the most promising genetic male sterility [4]. At present, there are 11 genes reported for male sterility in cotton, of which four are dominant (Ms4Ms7MslO,and Ms l1 ), four double recessive (msSms6msamsg) and three single recessive (ms 1ms2 and ms3). Due to the absence of genetic marker to differentiate between male sterile and fertile plants in cotton GMS system, it is not commercially utilized. So, the present study was aimed to induce male sterility through induced mutations which may also induce mutation in other characters to be linked to male sterility. As physical and chemical mutagen induced male sterility had been considered desirable as it has unique potential for the development of new MS genotypes directly, male sterility has been thus induced in more than 30 crop species including cotton. Irradiation with X-rays induced higher frequency of male sterility in G. hirsutum and G. arboreum cottons [5, 6). Several semi and complete sterile plants showing chromosomal aberrations at meiosis have been isolated when interspecific hybrids were gamma irradiated at 250-350 Gy. Ethyl Methane Sulphonate has also been used for induction of male sterility in cotton [7].