Tagging and Mapping of Yellow Vein Mosiac Virus Resistance Genes in Okra Abelmoschus esculentas and Development of New DNA Markers

Abstract

Okra (Abelmoschus esculentas L. Moench) or lady s finger is an important vegetable crop belonging to the Malvaceae family. Okra is considered to be a prized vegetable due to its high-nutrient value. Production and productivity of Okra is challenged by a number of biotic and abiotic factors. Yellow Vein mosaic virus (YVMV) disease caused by begomovirus and transmitted by whitefly (Bemisia tabaci) is an important biotic challenge. With an aim to identify new sources of resistance and DNA markers for the management of this disease, a set of 90 germplasm lines was screened in the field under natural condition. Six (6) genotypes exhibiting high resistance against YVMV infection consistently over two years were identified as new donor lines. Through characterization of four cross combination between most promising resistant and susceptible lines (AO: 189XAO:191, AO: 109XAO:191, AO: 133XAO:191 and AO: 133XAO:127) revealed resulted in identification of the cross combination AO: 189 X AO: 191 to be performing best against YVMV infection. This cross was subsequently used for the development of mapping population resulting generation of a mapping population of 143 individuals (F2:F3). newlineFurther, 143 individuals (lines) of the mapping population were characterized based on various morphological, pathological, biochemical parameters and disease reaction. The range of total chlorophyll in mapping population was observed from 2.22 to 0.79 mg/g tissue. The range of total Soluble Sugar in mapping population was observed from 21.52 mg/g to 0.79 mg/g tissue. The range of total phenol content in mapping population was observed from 0.21 mg/g to 0.04 mg/g tissue. On the basis of morphological, biochemical and pathological observations mapping population categorized into three categories viz resistant, tolerant and susceptible. Out of the 143 lines 48 lines revealed highly resistant feature, 64 lines were displayed tolerance while 29 lines fell to the susceptible category. newlineScreening of 360 DNA markers was performed to survey for parenta