Differences in responses to flooding by germinating seeds of two contrasting rice cultivars and two species of economically important grass weeds

Abstract

Barnyard grasses are serious weeds in direct seeded rice. We assessed the effectiveness of using controlled flooding for its control using two rice cultivars and two barnyard grasses contrasting in flood tolerance during germination. Flooding with 100 mm water after seeding suppressed barnyard grasses; but delaying flooding by 2-4 days was ineffective. Flooding increased the activity of alcohol dehydrogenase and pyruvate decarboxylase; the increase was higher in the tolerant rice cultivar but similar in both barnyard grasses. Aldehyde dehydrogenase activity increased only in flood-tolerant types of rice and weeds, but not in flood-sensitive types, implying potential role in tolerance.

Comprehensive metabolomic, proteomic and physiological analyses of grain yield reduction in rice under abrupt drought–flood alternation stress

“…The productive potential level of these super rice varieties of has been greatly improved recently, while at the same time increasing the demand for water and fertilization (Zeng et al , Xiong et al ). Previous studies using omics techniques for drought or flood were mostly concentrated on rice seedlings (He et al , Estioko et al , Jayaweera et al ). Via analysis of historical data of abrupt drought–flood alteration events (Cheng et al ), it was found that they often occurred in mid and late June in the Yangtze river basin.…”

Echinochloa crus‐galli seed physiological dormancy and germination responses to hypoxic floodwaters

“…Hypoxic floodwater during recruitment can seriously damage seedlings or waste seed reserves even in wetland species that are able to germinate underwater, such as rice and some Echinochloa species (Kennedy et al ; Crawford ; Fukao et al ; Chauhan & Johnson ; Ismail et al ; Estioko et al, ). Potential strategies to avoid lethal underwater germination could include both a requirement for high O 2 levels to germinate and the maintenance (or reinforcement) of dormancy during the flood period, which may be reduced as soon as water recedes (Mollard et al ; Mollard & Insausti ).…”

Preventive Weed Management in Direct-Seeded Rice

“…Early flooding of !5 cm Early shallow flooding (0.5-2 cm) at 0 days after sowing (DAS) did not affect emergence but shoot length was reduced but had no effect when flooding was delayed by 4 DAS. Deep flooding of 10 cm at 0 DAS also did not affect emergence, however, its root ($99%) and shoot lengths (80%) were highly suppressed (Estioko et al, 2014) Estioko et al 2014In contrast, other studies observed reduction in emergence at 4-cm flooding depth. Variations in results suggest differential response of biotypes adapted to different environments and management strategies Chauhan and Johnson (2011) Echinochloa colona…”

“…But root and shoot lengths were suppressed when flooding was initiated at 0 and 2 DAS. Deep early flooding of 10 cm at 0 DAS reduced emergence by 97% compared to no flooding control Estioko et al (2014) Echinochloa glabrescens…”