Morpho-physiological responses of mungbean (Vigna Radiata (L.) R. Wilczek) to salinity stress at different growth stages

Yee Phyo That

Date

6-2025

Abstract

Salinity is a significant abiotic stressor that reduces crop productivity, especially in arid regions. Mungbean (Vigna radiata L.), an important legume, is somewhat susceptible to salinity stress, which affects growth from seed germination to pod filling. This study aims to identify morpho-physiological variations in mungbean responses to salinity at different growth stages.

Three experiments were conducted to test the response to salinity of several mungbean genotypes at germination, vegetative and reproductive stages, under laboratory and greenhouse conditions using 3 salinity levels, 0 mM. 50 mM and 100 mM NaCl.

At the germination stage, computed seedling vigor index and tolerance index based on germination percentage and root and seedling lengths, were able to differentiate the performance of 20 mungbean genotypes. Among these 4 breeding lines and 3 varieties were shown to be resistant and susceptible to salinity respectively. These 7 genotypes were further tested for salinity response at vegetative stage and grown under hydroponics culture system supplemented with salt. Roots were collected at 21 days after sowing and scanned and analyzed using WinRhizoTM, Results showed that among total root length, root surface area,average root diameter, and root volume, significant differences due to the salt treatment only were observed for average root diameter. In study 3, the root:shoot ratio based on dry matter and harvest index were significantly affected by the salt treatment. PCA analysis revealed that yield-related root characteristics (root dry weight. root:shoot ratio) and reproductive metrics (seed weight, pod weight) are key indicators of mungbean salinity tolerance.

These results imply that certain genotypes of mungbean have physiological characteristics that allow for adaptation to salt, such as persistent seedling vigor, deeper root systems, bigger root diameters,and harvest index. Based on the results, the response to salt at the different growth stages can differ. However, for areas that are already saline, the germination studies show that the presence of genotypic differences are important to select for genotypes that will thrive in saline areas such as coastal areas, or production areas that are highly fertilized and arid. It is recommended that more studies should be conducted to have a deeper understanding of the physiological response of mungbean to salinity stress, and validate specific traits related to salinity tolerance.

Document Type

Dissertation

Degree

Doctor of Philosophy in Agronomy

College

Graduate School (GS)

Adviser/Committee Chair

Eureka Teresa M. Ocampo

Committee Member

Pearl B. Sanchez, Antonio G. Lalusin, Ma. Lourdes S. Edaño

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

En – AGROVOC descriptors

501 VIGNA RADIATA RADIATA; OSMOTIC STRESS; PLANT MORPHOLOGY; PHYSIOLOGICAL RESPONSE; SPROUTING OF SEED

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