Response of U.S. Rice Cultivars Grown under Non-Flooded Irrigation Management

Abstract

Achieving food security along with environmental sustainability requires high yields with reduced demands on irrigation resources for rice production systems. The goal of the present investigation was to identify traits and germplasms for rice breeding programs that target effective grain production (EGP) under non-flooded field systems where the crop can be subjected to intermittent water stress throughout the growing season. A panel of 15 cultivars was evaluated over three years regarding phenological and agronomic traits under four soil moisture levels ranging from field capacity (29% volumetric water content; VWC) to just above the wilting point (16% VWC) using subsurface drip irrigation. An average of 690 ha-mm ha−1 water was applied for the 30% VWC treatment compared to 360 ha-mm ha−1 for the 14% VWC treatment. The average soil moisture content influenced several traits, including grain quality. Regression analysis identified six traits that explained 35% of the phenotypic variability of EGP. Four varieties (PI 312777, Francis, Zhe 733, and Mars) were found possessing significant slopes for 10 or more traits that respond to a range in soil moisture levels, indicating that they may offer promise for future rice breeding programs. Furthermore, based on the contrasting responses of four parent cultivars, two mapping populations were identified as potential genetic resources for identifying new quantitative trait loci/genes for improving EGP of tropical japonica rice varieties.

Effects of alternate wetting and drying irrigation management and air temperature during grainfill on rice grain physicochemical and functionality traits of US inbred varieties

“…As it is conventionally grown in flooded paddies, rice crop production is one of the largest users of irrigation resources and is expected to increase with the global population anticipated to reach nearly 10 billion by 2050 (Elliott et al, 2014). Thus, researchers have been investigating ways to reduce water inputs for sustainable rice production without a penalty on grain yield and quality (McClung et al., 2020).…”

“…US rice farmers have shown interest in adopting AWD irrigation management systems in commercial rice fields (McClung et al., 2020). Rice produced in the USA is for both domestic and export markets, and to remain competitive, US rice needs to maintain premium grain quality (McClung et al., 2019).…”

Socio-Technical Changes for Sustainable Rice Production: Rice Husk Amendment, Conservation Irrigation, and System Changes

“…Increasing ROS scavenging would likely also increase tolerance to temperature stress (Zhu et al, 2020) that can affect grain yield, kernel size, milling quality, and chalkiness (Counce et al, 2005;Xu et al, 2020). Further investigation should determine which mechanisms best allow rice plants to avoid or tolerate stress from intermittent water deficits and can benefit from recently developed visual stress rating tools (McClung et al, 2020).…”

Physiological and Multi-Omics Approaches for Explaining Drought Stress Tolerance and Supporting Sustainable Production of Rice

“…The negative implications of drought stress on the physiological functioning of plants are mainly due to its reduced water potential and turgor pressure that suppress plant growth and metabolism (Lisar et al, 2012). Drought is a period in crop's growing season during which the soil moisture reaches to a certain level that reduces its yield or quality resulting from either limited irrigations or a below average rate of precipitation and higher evapo-transpirations, which causes a decline in plant growth and productivity (Rollins et al, 2013;McClung et al, 2020). Drought affects plants in numerous ways by impairing normal molecular, metabolic and physiological networks to reduce growth and metabolism (Zu et al, 2017).…”

“…Currently, farmers are practicing safe-AWD levels because most current varieties are bred for seasonlong flood irrigation management under both lowland and upland rice cultivations. In AWD, there is a drying phase, and rice is susceptible to drying conditions, because they affect yield and grain quality (McClung et al, 2020). Shaibu et al (2015) compared Nunkile and NERICA 4 rice varieties, which are adapted to upland and lowland irrigated conditions, under continuous flood and three different AWD schemes.…”