Effects on rice plant morphology and physiology of water and associated management practices of the system of rice intensification and their implications for crop performance

Abstract

Field experiments were conducted in Bhubaneswar, Orissa, India, during the dry season (JanuaryMay) in 2008 and 2009 to investigate whether practices of the System of Rice Intensification (SRI), including alternate wetting and drying (AWD) during the vegetative stage of plant growth, could improve rice plants' morphology and physiology and what would be their impact on resulting crop performance, compared with currently recommended scientific management practices (SMP), including continuous flooding (CF) of paddies. With SRI practices, grain yield was increased by 48% in these trials at the same time, there was an average water saving of 22% compared with inundated SMP rice. Water productivity with AWD-SRI management practices was almost doubled (0.68 g l -1 ) compared to CF-SMP (0.36 g l -1 ). Significant improvements were observed in the morphology of SRI plants in terms of root growth, plant/culm height, tiller number per hill, tiller perimeter, leaf size and number, leaf area index (LAI), specific leaf weight (SLW), and open canopy structure. These phenotypic improvements of the AWD-SRI crop were accompanied by physiological changes: greater xylem exudation rate, crop growth rate, mean leaf elongation rate (LER), and higher light interception by the canopy compared to rice plants grown under CF-SMP. SRI plants showed delayed leaf senescence and greater light utilization, and they maintained higher photosynthetic rates during reproductive and grain-filling stages. This was responsible for improvement in yieldcontributing characteristics and higher grain yield than from flooded rice with SMP. We conclude that SRI practices with AWD improve rice plants' morphology, and this benefits physiological processes that result in higher grain yield and water productivity.

Impact of water management on root morphology, growth and yield component of lowland rice varieties under the organic system of rice intensification

“…Thakur et al (2011) reported that the higher value of CGR with aerated rice field by draining the flood water for some time as compared to continuous flooding is similar to this observation. Note : The numbers in the same column followed by the same letter are not significantly different according to DMRT 5%…”

“…The dry weight of root was higher under intermittent irrigation, which could indicate a strong water and nutrient absorption capacity translating into high grain production (Pascual and Wang, 2017). Thakur et al (2011) in their study reported that the proportion of roots that were brown or black (non-functional and decayed) was found to be higher in continuously flooded plots compared with aerated rice fields. Pascual and Wang, 2017 added that roots of plants grown under continuous flooding regimes also showed a higher proportion of decayed or nonfunctional parts compared with those under intermittent irrigation.…”

“…World food security remains largely dependent on irrigated lowland rice, which is the main source of rice supply (Yang and Zhang, 2010). Fresh water for irrigation is becoming scarce because of population growth, increasing urban and industrial development, and the decreasing availability resulting from pollution and resource depletion (Chapagain et al, 2011 ;Thakur et al, 2011). Asia contributes more than 90% of the world's total rice production while using more than 90% of the total irrigation water (Khepar et al, 2000).…”

Effect of Different Crop Establishment Techniques on Growth, Yield attributes and Yield of Rice Under Puddled Condition

“…The tallest plants under square planting (SRI) with single seedling method might be due to optimum plant population and geometry which led to availability of more resources to plants. The increased LAI in square planting (SRI) with single seedling method was due to open plant structure giving more coverage to the (Thakur et al, 2011). The higher dry matter accumulation in square planting (SRI) with single seedling might be attributed due to wider spacing which resulted in more tiller production, number of leaves, LAI and improved root characters.…”

Advances in crop phenotyping and multi-environment trials

“…[1] . The scientific significance of crop characterization techniques lies in accurately and rapidly acquiring phenotypic and genotypic data for the discovery of intrinsic connection between various characteristics, whereas the practical significance is to develop elite cultivars for production [2][3][4][5][6][7][8] .…”