Residual Effects of MSMA on Sterility in Rice Cultivars¹

Abstract

Abstract In a study conducted in 1975, sterility in rice ( Oryza sativa L.) cultivars grown on Crowley silt loam soil (Typic Albaqualf) amended with monosodium methanearsonate (MSMA) increased as cultivar susceptibility to straight‐head increased. A midseason drain and dry treatment was found to decrease MSMA induced sterility. This study was a continuation of the experiment initiated in 1975 to evaluate the residual effects of the 1975 MSMA application on rice growth and yield 2 and 4 years later for two water management schemes. Two rice cultivars (‘Lebonnet’ and ‘Nova 76’ or ‘Mars’) of different straighthead resistance were grown in rotation with ‘Lee 74‘ soybean ( Glycine max L. Merr.). Two years after application of MSMA, sterility and decreased yield were observed under continuous flood for the 11.2 kg arsenic/ha rate with the straighthead susceptible cultivar (Nova 76) being damaged more severely. No damage was found at this arsenic (As) rate for the midseason draining and drying treatment, a common straighthead control practice, or for either water management at the 1.1 kg As/ha rate. Four years after MSMA application, no sterility or yield reduction were noted in any treatment. These data suggest that where rice production is desired on a silt loam soil previously treated with MSMA crop rotation, in addition to cultivar selection and water management, could be used to minimize yield loses due to sterility.