Response of selected onion (Allium cepa L.) cultivars to different waterlogging duration and seed priming at two growth stages

Date

12-2025

Abstract

Waterlogging is highly damaging to onions and can result in total crop failure. Response of eight onion cultivars (Dambulla Selection, MIBO 1, Rampur Red, Rampur Rose, Galewela Selection, Nasic Red, Avatar, and MICLO 1) were evaluated at 3, 5, and 10 days of waterlogging duration in a split plot experiment to determine tolerance at seedling (BBCH 103) and 20 days after transplanting (DAT) (BBCH 401) growth stages. Using a waterlogging tolerance coefficient (WTC) index, considering survival% and recovery%, MICLO 1, Avatar and Nasic Red were categorized as tolerant at seedling stage. The phenotypic traits associated with these cultivars include higher stomatal conductance and relative water content at 3 days waterlogging duration, higher root: shoot dry weight at 3- and 5-days waterlogging, and higher root surface area at all waterlogging durations compared to control. Additionally, cultivar MICLO 1 had higher number of roots after 5 days of waterlogging and higher root volume and low root electrical leakage at up to 10 days waterlogging. MICLO 1 was the only cultivar categorized as highly tolerant at 20 DAT. Associated traits were higher root surface area, and root volume at 5 and 10-days waterlogging durations, higher root: shoot dry weight, relative chlorophyll content, and relative water content at 3 days waterlogging duration. Bulb size was larger, dry matter content and total sugar content were higher than the control up to 5 days of waterlogging while total soluble solid content remained high up to 10 days of waterlogging. Pungency however, was reduced by waterlogging. More importantly, MICLO 1 had the highest WTC on yield compared with the other cultivars across waterlogging durations, attaining high yield (12.6 t/ha) similar to its control (12.8 t/ha). Selecting cultivars for waterlogging tolerance is more reliable when conducted at 20 days after transplanting stage compared to seedling stage.

Another field study determined if seed priming and exogenous application of KNO3 will improve survival and tolerance to waterlogging using MIBO 1(farmers' cultivar) and 10 days of waterlogging duration, 0.1% KNO3 soil application at 48 hours before waterlogging, compared to control 1 (no KNO3, 10 days waterlogging), had a higher positive contribution to the majority of agronomical, physiological, and chemical parameters as well as increased bulb size and yield. Caution that at 10d waterlogging duration, yield levels were low. Further evaluation is needed before giving recommendations.

Document Type

Dissertation

Degree

Doctor of Philosophy in Horticulture

College

Graduate School (GS)

Adviser/Committee Chair

Edna A. Aguilar

Committee Member

Calixto M. Protacio, Elda B. Esguerra, Tonette P. Laude

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

En – AGROVOC descriptors

ALLIUM CEPA; ONIONS; STOMATAL CONDUCTANCE; WATER TOLERANCE; WATERLOGGING; PLANT MORPHOLOGY

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