Morphological and dry matter yield of rice genotypes in response to drought stress and rewatering at vegetative stage

Issue Date

7-2018

Abstract

Screening of drought-tolerant rice genotypes has focused on water use efficiency and maximizing grain yield under rainfed lowland condition. However, it is equally important to assess plant morphological responses such as leaf rolling and leaf tip drying as they are practical drought stress indicators and also influence yield. This pot study in the screenhouse exposed 17 rice genotypes to drought stress at vegetative stage for 20 days (i.e., 15-35 days after transplanting or DAT), rewatering for 10 days (i.e, 36-46 DAT), and assessed soil water status, plant morphological changes, and aboveground dry matter yields. Each pot had a volume of 10 L and contained 8 kg of well-fertilized Maligaya clay soil. Soil moisture content and soil strength were assessed by gravimetric and penetrometer methods, respectively. Results showed that the 20-day drought treatment period was characterized by the decrease in average soil moisture content from 60.5 to 0.7% and increase in average soil strength from 0 to 3.0 MPa across the drought treatment pots. Out of 17 rice genotypes tested, only 8 genotypes namely: PSB Rc14, NSIC Rc416, GSR-21, RAELINE-10, NSIC Rc282, CT 9993-5-10-1-M, UPL Ri-5, and NSIC Rc160 survived after the vegetative drought stress and rewatering treatments. The performance of these genotypes could be attributed to slow progression of leaf rolling [i.e., scores of 1 to 4 for the 8 genotypes vs. 1 to 5 (tightly rolled) for the rest of the genotypes], leaf tip drying [i.e., scores of 1 to 4 vs. 1 to 5 (100% drying of leaf the lamina)], and lower reduction in aboveground dry matter yield based on the well-watered Control. Moderate or slow progression of leaf rolling and leaf tip drying could have contributed to relatively higher photosynthetic activity by maintaining photosynthetic leaf area thereby minimizing reduction in dry matter yield.

Source or Periodical Title

Philippine Journal of Crop Science

ISSN

0115-463X

Volume

43

Issue

Supplement no. 1

Page

72-73

Document Type

Article

Language

English

Subject

Rice; Drought-tolerant plants

En – AGROVOC descriptors

ORYZA SATIVA; GENOTYPES; DROUGHT RESISTANCE; DROUGHT STRESS; WATERING; LEAVES; BIOMASS

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