“PHYSIOLOGICAL AND MOLECULAR CHARACTERIZATION FOR IDENTIFICATION OF DROUGHT TOLEARNT GENOTYPES IN OKRA (Abelmoschus esculentus L.).”
Loading...
Date
2019-11
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
University of Horticultural Sciences, Bagalkot
Abstract
Okra (Abelmoschus esculentus L.) is commonly known as bhendi or lady‟s finger, belongs to family Malvaceae having a somatic chromosome number (2n=130) and originated in Ethiopia. Okra is exposed to diverse biotic and abiotic stresses which results in the reduced yield. Among them drought stress is most important stress causing yield loss. Drought tolerance mechanism can be understand by observing the performance of crop while studying the various growth factors, physiological, morphological adaptations and expression of drought responsive genes. Characterization and identification of drought tolerant genotypes is one of viable option to reduce yield loss.
In the present study 20 okra genotypes procured from different zones were initially characterized for growth, flowering, yield and seed parameters. The characterization reveals that the genotypes viz., Arka Abhay, Parbhani Kranthi, COH-1 and P-8 showed higher growth and yield performance. To find drought tolerance these 20 genotypes were imposed to water stress (moderate and severe stress with control) under pot condition were grown in rain out shelter structure were evaluated for drought tolerant traits like specific leaf weight, relative water content, chlorophyll content, SPAD values, root length, root diameter, 13C isotope and proline content. Analysis of drought specific traits shows three out of twenty genotypes viz., COH-1, UHSCOHB-1 and Bagalkot local were found relatively drought tolerant, while CBR-2 and UHSCOHB-3 genotypes were found relatively drought susceptible.
The m-RNA expression profiling was carried out using one drought tolerant genotype (COH-4) and drought susceptible genotype (CBR-2) by qRT-PCR analysis using drought stress specific upstream regulating transcription factors viz.,LEA 2A, GhDREB, HSP and GbMYB2. The genotypes were exposed to severe water stress, from which leaf m-RNA extracted was converted into cDNA then subjected to qRT-PCR. The expression profiling pattern from qRT-PCR revealed out of four transcription factors the LEA 2A and GhDREB were over expressed (fold change) under drought stress conditions in drought tolerant genotype (COH-4) compared to susceptible genotype (CBR-2).