Identification of resistant genotypes of okra and virus associated with Bhendi yellow vein mosaic disease
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Date
2018
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Publisher
Division of Vegetable Science Indian Agricultural Research Institute New Delhi –
Abstract
Okra [Abelmoschus esculentus (L.) Moench, 2n=2x=130] known as Bhendi
or lady’s finger is one of the important vegetable crops of Malvaceae family. It is one of the
popular vegetables grown commercially by the farmer’s almost round the year in one or another
parts of the country which fetches them higher profit. Though India is the largest producer of
okra in the world, but its production is constrained by several abiotic and biotic factors. Among
them Bhendi Yellow Vein Mosaic disease (BYVMD) is the most serious one which infects all
plant parts including fruits and in severe cases may leads to 100% yield loss. Due to presence
of sterility in inter specific hybridization of okra and emergence of new viruses through
recombination or mutation, the management of BYVMD has come to a standstill. Keeping
above facts in mind, 15 diverse selected genotypes of okra were screened under natural
condition for better understanding of the expression of yield attributing traits, source of
resistance and identification of viral strain associated with BYVMV disease through molecular
technique. Pusa Sawani and DOV 22 were found to be highly susceptible to BYVMV and very
high level of infections i.e. 25% and 22% were observed within 30 days of sowing. Thee
genotypes namely, Punjab 8, DOV66 and DOV 92 were found highly resistant to BYVM
disease and only few plants showed YVMV symptom even after 75 days after sowing. The
rolling circle amplification (RCA) and cloning of virus DNA present in susceptible genotypes
showed 99% sequence similarity with Bhendi Yellow Vein Mosaic Virus.This confirmed the
presence of the Bhendi Yellow Vein Mosaic Virus (BYVMV) in the YVMV diseased caused
by virus in okra genotypes in our study in north Indian condition particularly in New Delhi.
Several genotypes were identified as desirable for various yield and yield attributing traits,
namely Pusa Bhind-5 (DOV-66) for earliest days to 50% flowering (45.33 days), Punjab 8 for
higher numbers of nodes on main stem (17.53) and highly branched growth habit, IC-685583
for small intermodal length (4.19 cm), DOV-2-4-5 for number of fruits per plant (18.54) and
DOV-92 (181.67 g) yield per plant. High heritability coupled with high Genetic Advance
percent over Mean were estimated for yield attributing traits, viz. fruit yield per plant, fruit
length, fruit diameter, fruit weight etc. which revealed the predominance of additive gene
effects. Correlation coefficient analysis showed positive and significant correlation of fruit
yield per plant with fruit weight (0.942**), number of fruits per plant (0.717**), number of
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nodes on main stem (0.503**) and days to 50% flowering (0.455**) while its correlations with
disease incidence were negative. Path coefficient analysis revealed positive direct effects of
fruit weight, inter nodal length, number of fruits per plant, days to 50% flowering and fruit
length on fruit yield per plant. These characters would have direct influence on fruit yield. This
type of information would support plant breeder to trace yield influencing component and
employ it in crop improvement programme. Three genotypes, namely Punjab 8 (133.27), Pusa
Bhindi-5 [DOV66] (171.86g) and DOV 92 (181.67g) were found high yielding with several
desirable yield attributing traits and highly resistant to Bhendi Yellow Vein Mosaic Virus
disease of okra under Delhi condition.
Description
t-9867
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