ARS | Publication request: DIFFERENTIAL RESPONSE OF RICE (ORYZA SATIVA L.) GERMPLASM TO STRAIGHTHEAD INDUCED BY ARSENIC

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 7, 2004
Publication Date: July 1, 2005
Citation: Yan, W., Dilday, R.H., Tai, T., Gibbons, J., Rutger, J.N. 2005. Differential response of rice (Oryza sativa L.) germplasm to straighthead induced by arsenic. Crop Science. 45:1223-1228.

Interpretive Summary: Straighthead disease is a physiological disorder of rice characterized by sterility of the florets leading to reduction of grain yield. Up to 35% of rice fields in Arkansas is using the practice of draining and drying for straighthead prevention, which adds costs for rice production. Knowledge of the straighthead response of new cultivars is important for producer control of this disease, and identification of resistant germplasm is essential for breeding improved cultivars. This test found that US cultivar Cocodrie, Mars, Kaybonnet and Bengal were highly susceptible to straighthead with straighthead ratings up to 8.8 and yield reductions up to 99%. US cultivar Wells, LaGrue, Drew, Cypress and Japanese cultivar 92.09.31 were susceptible with ratings up to 6.8 and yield reductions up to 79%. US cultivar Priscilla and Jefferson were tolerant with ratings up to 5.5 and yield reductions up to 51%. Chinese indica cultivar Zhe 733 was essentially immune to straighthead, showing neither symptoms nor detectable yield reduction. Eighteen Chinese cultivars including 17 indica and 1 japonica were identified as straighthead resistant in an evaluation program including 124 cultivars. Variation in plant height, maturity, and endosperm type within the resistant germplasm was also observed. In combination, susceptible Cocodrie, Cypress and Wells were grown on 73% of rice hectares in 2001, which is a potential threat to the production. Integrating straighthead resistance from the germplasm into the high-yielding US cultivars should play important role in reducing production costs and stabilizing rice production in the Southern US.

Technical Abstract: Straighthead disease is a physiological disorder of rice characterized by sterility of the florets leading to reduction of grain yield. Knowledge of the straighthead response of new cultivars is important for producer control of this disease, and identification of resistant germplasm is essential for breeding improved cultivars. Ten US cultivars were tested for straighthead reaction induced by monosodium methanearsonate (MSMA) at 0, 6.7 and 9.0 kg ha-1 under nitrogen fertilizer of 0, 67, 134 and 269 kg N ha-1 in 1999 and 2000. Cocodrie, Mars, Kaybonnet and Bengal were highly susceptible to straighthead with ratings from 7.0 to 8.8 and yield reductions from 92 to 99%. Wells, LaGrue, Drew, Cypress and Japan 92.09.31 were susceptible with ratings from 4.8 to 6.8 and yield reductions from 47 to 79%. Priscilla and Jefferson were tolerant with ratings from 4.3 to 5.5 and yield reductions from 23 to 51%. The Chinese indica cultivar Zhe 733 was essentially immune to straighthead, showing neither symptoms nor detectable yield reduction. A total of 124 Chinese cultivars including 109 indica and 15 japonica were evaluated for straighthead resistance in 2001. Eighteen cultivars including 17 indica and 1 japonica were identified as straighthead resistant. Variation in plant height, maturity, and endosperm type within the resistant germplasm was also observed.