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ARS Home » Southeast Area » Stuttgart, Arkansas » Dale Bumpers National Rice Research Center » Research » Publications at this Location » Publication #358267
Research Project: Gene Discovery and Crop Design for Current and New Rice Management Practices and Market Opportunities

Location: Dale Bumpers National Rice Research Center

Title: Genetic potential of rice under AWD irrigation management for barnyardgrass suppression and grain yield production

Author
item Gealy, David
item Rohila, Jai
item Boykin, Deborah

Submitted to: Weed Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/25/2019
Publication Date: 7/17/2019
Citation: Gealy, D.R., Rohila, J.S., Boykin, D.L. 2019. Genetic potential of rice under AWD irrigation management for barnyardgrass suppression and grain yield production. Weed Science. 67:453-462.

Interpretive Summary: Barnyardgrass (BYG) is one of the most troublesome and competitive weed species in rice grown under conventional flood (FLD) irrigation systems in the southern US, and it may also be highly damaging to rice grown under newly-developed water-saving irrigation systems such as alternate-wetting-and-drying (AWD) in which soils in rice fields are allowed dry down naturally and reflooded only intermittently during the crop season. Several indica rice types have been shown to suppress BYG under FLD irrigation, but very little is known about their weed suppression potential under AWD irrigation. In a three-year field study, we evaluated three commercial tropical japonica [TRJ] types, two indica types, an indica-TRJ cross, and a hybrid to determine their weed suppression and grain yield (GY) potential under FLD and AWD irrigation. Under AWD the BYG dry weight at mid-season averaged 11% less compared with the FLD, indicating that the combination of rice growth and AWD irrigation slightly reduced the weed growth. Overall, indica and hybrid types reduced BYG dry weight the most under AWD compared with the FLD. On average, rice GY in weed-free AWD plots was only 12% less than in weed-free FLD plots. However, GY of Bengal, a TRJ, was 32% lower under AWD than FLD, whereas GYs of the two indica types, PI 312777 and Rondo, and the hybrid were similar in the two irrigation systems, which indicated that rice types differ dramatically in their sensitivity to AWD stress. GY was reduced more than 90% in all weed-infested plots, indicating that weeds were a much greater source of stress to rice than was AWD in this study. Key findings of the study were that BYG greatly reduced the GY of all rice types tested in both FLD and AWD systems, and that GY of the indica and hybrid types were relatively less affected by the AWD conditions compared with most commercial TRJ types. Thus, weed-suppressive types such as PI3122777 may be especially suitable for AWD irrigation systems and for inclusion in weed-suppression breeding programs for rice improvement, whereas TRJ types such as Bengal may be less suitable.

Technical Abstract: Barnyardgrass (BYG) is one of the most troublesome and competitive weed species in rice grown under conventional flood (FLD) irrigation systems in the southern US, and it is expected to be similarly damaging as new water-saving systems such as alternate-wetting-and-drying (AWD) irrigation are implemented. Several indica rice genotypes have been shown to suppress BYG under FLD irrigation, but very little is known about the nature and potential of weed suppression under AWD irrigation. In a three-year field study, we evaluated seven diverse rice genotypes for their weed suppression and grain yield (GY) potential under FLD and AWD irrigation. These genotypes included three commercial tropical japonica [TRJ] types (Bengal, Katy, and Cheniere), two indica types (PI 312777 and Rondo), an indica-TRJ cross (STG06L-35-061), and a hybrid (XP753). Under AWD the BYG dry biomass at mid-season was 11% less compared with the FLD. Overall, indica and hybrid genotypes reduced BYG dry biomass the most under AWD compared with the FLD. Rice GY in weed-free AWD plots averaged 12% less than in weed-free FLD plots, but GY of the TRJ, Bengal, was 32% lower under AWD than FLD, whereas GYs of the two indica genotypes, PI 312777 and Rondo, and the hybrid were similar in the two irrigation systems. GY reduction in BYG-infested AWD plots averaged more than 90%. Thus, BYG reduced the GY of all rice genotypes tested in both FLD and AWD systems dramatically in this study. GY of the indica and hybrid genotypes were relatively less affected by the AWD conditions compared with the TRJ genotypes, particularly Bengal, suggesting that weed-suppressive genotypes such as PI3122777 are suitable for AWD irrigation systems and for inclusion in weed-suppression breeding programs of rice.