Physiological and Agronomic Responses of Four Rice Varieties to Drought in the Rainforest

Abstract

The present investigation tested the hypothesis that there would be variation in physiological responses to water deficit among rice varieties from different production ecologies, with contrasting tolerance to water deficit under repeated cycle of soil moisture deficit, at reproductive growth stage. A screen house and a field trial were conducted at International Institute of Tropical Agriculture, Ibadan and Ikenne (Latitude 6° 52' N, Longitude 3° 43' E) respectively. Both experiments had rice varieties (‘IR 64’, ‘WAB 56-104’, ‘IR 77298-1-2-B-10’ and ‘NERICA 4’) and stress status (stress and control) as treatment factor’s, arranged in a randomised complete block design with three replicates. In both trials, the physiological mechanism that underpins varietal differences with repeated cycles of water deficit at the reproductive growth stage was more balanced water status, improved foliar characters, efficient photosynthetic capacity and higher grain yield in comparatively drought tolerant upland rice varieties (‘NERICA 4’ and ‘WAB 56-104’), as opposed with the results for the drought susceptible cultivar ‘IR 64’. A converse pattern was observed on water stressed rice, despite fewer cycles of water deficit on the field. The results could have suggested that the initiation of water deficit is the rate limiting step rather than its intensity at the reproductive growth stage.

Effect of intermittent drought on grain yield and quality of rice (Oryza sativa L.) grown in Rwanda

“…To conclude from both these fields and the previous biotron (Mukamuhirwa et al, ) studies, severe drought conditions during early plant development impacted panicle development, thus affecting grain yield, whereas drought at the reproductive stage results in a stronger impact on spikelet fertility. Also, previous research has shown impact of drought on spikelet sterility, thereby affecting grain yield (Fofana et al, ; Moonmoon & Islam, ). The results of the present study indicate spikelet fertility and weight of 100 grains as important grain yield components having an impact on total grain yield.…”

Integrated Research for Development Approach to Upgrade the Whole Rice Value-chain in Sub-Saharan Africa: Contribution of Africa Rice Center after NERICA (New Rice for Africa)

“…The start of breeding for interspecific (NERICA) varieties between Oryza sativa and Oryza glaberrima was in 1992 (Jones et al 1997) and the first release of NERICA varieties was in 2002 in Côte d'Ivoire and Guinea. All upland NERICA varieties possess short growth duration and comparable yield with improved upland varieties (Somado et al 2008) and have the respective advantages such as NERICA 4 with drought tolerance (Fofana et al 2018), which has become popular in SSA especially in Uganda because of the drought tolerance (Britwum et al 2020). In addition to the numbered NERICA varieties-i.e.…”