Poster: Molecular & Cellular Plant-Microbe Interactions: MPMI
Evaluation of Rice Varieties for Resistance for Autumn Decline in Arkansas
H. Yan (1), H. Zhang (2), M. Kim (3), B. Yoon (4), W. Shim (4) (1) Texas A&M University, Plant Pathology & Microbiology, Texas A&M University, College Station, TX, 77843, U.S.A.; (2) Texas A&M University, Plant Pathology & Microbiology, Texas A&M Universi
Symptoms of autumn decline include black root rotting with stunted and yellowish rice foliage starting as early as two weeks following permanent flood establishment. The problem is often most severe where cold well water first enters a rice field and may spread throughout the field, except on levees. The phenomenon was reported in Arkansas in a limited number of fields in 2004. However, there were several reports of autumn decline across the state of Arkansas in 2012 to 2015. Observations have shown fields having a clay loam soil texture as more prone to the autumn decline phenomenon than others commonly cropped to rice. The root rotting symptoms often start a few weeks after flood establishment and become progressively worse throughout the season if unmitigated. In situations where root rotting is severe, fungi grow into the crown which limits function of the whole root system and prevents translocation of water and nutrients from the soil to the plant. In moderate to severe cases, tillers break off easily and plant death may occur rapidly leading to significant yield losses. Twenty commercial rice varieties were evaluated in the field in 2015 and based on their reactions a rating scale was developed. The nature of autumn decline problem, reactions of the varieties and the rating scale will be presented.