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    ThesisItemOpen Access
    DEVELOPMENT OF DOUBLED HAPLOID BACTERIAL BLIGHT RESISTANCE GENOTYPES OF BASMATI RICE (Oryza sativa L.) THROUGH ANTHER CULTURE
    (School of Biotechnology Sher-e-Kashmir University of Agricultural Sciences & Technology of Jammu , Jammu, 2020-01) Sharma, Mridhu; Singh, A.K
    The present study entitled “Development of doubled haploid bacterial blight resistance genotypes of Basmati rice (Oryza sativa L.) through anther culture” was undertaken with the objectives to screen the BC2F1 population for xa13 and Xa21 bacterial blight (BB) resistance genes using molecular markers, standardization and development of doubled haploid bacterial blight resistant genotypes of BC2F1 population and identification and evaluation of doubled haploid plants carrying xa13 and Xa21 bacterial blight resistance genes in Basmati rice. Although traditional plant breeding methods have been considerably contributing to incorporate resistance to major diseases; advanced technologies to complement conventional breeding procedures have to be employed. Production of doubled haploids (DHs) through anther/microspore culture is a rapid approach to attain homozygosity that can shorten the time required to develop a cultivar. Doubled haploid (DH) techniques have been successfully established in economically important crop species, including major cereals like rice, wheat etc. to meet the requirements of people, as it is the staple food in South-east Asian countries. Solidified N6 medium supplemented with 2,4-dichlorophenoxy acetic acid (2,4-D) (2.5 mg l-1), kinetin (0.5 mg l-1) and naphthalene acetic acid (NAA) (2.0 mg l-1) was found optimum for callus induction (CI) with CI frequency of 10.07 percent. The induced callus was sub cultured for shoot regeneration on Murashige and Skoog medium (MS) supplemented with growth regulators, of which kinetin (0.5 mg l-1), NAA (0.5 mg l-1) and BAP (1.5 mg l-1) was most responsive exhibiting regeneration frequency of 28.1 percent green plantlets and lowest albino induction frequency of 5.21 percent. Individual plantlets were separated and immersed in liquid MS medium augmented with NAA (0.5 mg l-1) and BAP (1.0 mg l-1) as best rooting media. The media augmented with combination of amino acids tryptophan (25 mg l-1) and cysteine (40 mg l-1) resulted in increased callus induction frequency of 12.55 per cent. All data recorded were subjected to completely randomized design (CRD) using OPSTAT software (version 7.2.2007).The survival rate of in-vitro raised plants was 51.51 per cent with thirty-four surviving plants of which 61.76 percent (twenty-one) plants were doubled haploids which were then screened phenotypically and genotypically for BB resistant genes. When the DH plants were infected with Xanthomonas oryzae pv. oryzae (Xoo), only one plant DH8 showed moderately susceptible reaction and one plant (DH20) showed moderately resistant reaction. The SSR markers polymorphic for both the parents were run on DH plants to get the homozygous plants. Most of the genotypes depicted resistant (R) response and clear effect of introgressed genes could be observed. The agro-morphological traits were subjected to t-test using GraphPad Prism 8.3. Thus, inspite of several limitations, anther culture technique holds promise to develop true breeding DH lines and for introgressing desirable genes into the elite backgrounds.