Adaptability of the Arginine Maturity Index Method To Virginia Type Peanuts in North Carolina1

Abstract

Abstract The Arginine Maturity Index (AMI)- method for estimation of optimum maturity and highest quality of peanuts was evaluated in a two-year research station study (1977 and 1978) of large-seeded Virginia type peanuts grown in North Carolina. A one year study was conducted on farms in seven North Carolina counties in 1978. Samples were collected weekly from both the research station and farms and analyzed for arginine by the modified Sakaguchi reaction. Maximum yield corresponded to minimum AMI values for each cultivar in 1977 and for the NC 5 cultivar in 1978 in the research station study. Prediction curves were derived from each cultivar for each year using a quadratic polyonomial equation. Large differences in AMI data existed between 1977 and 1978 and between cultivars in 1978 at early harvest dates; however, near minimum AMI values, all six curves appear to be similar. AMI and yield data obtained from individual county farms fluctuated throughout the growing season. Generally, higher AMI values were observed for Virginia type than have been reported for Spanish type peanuts. Using the prediction curve derived in Georgia, and subtracting one week, predicted digging dates were within 4 days of the date of maximum dollar return per ha in five of the seven counties. Based on previous experience, the farm data of six counties (with the exception of Nash), was used to derive a tentative optimum harvest prediction equation for North Carolina.