ABSTRACT

Delta and Pine Land Company (D&PL) conducts an aggressive field variety development program. Varieties at early stages of development are widely tested in small plot, but during the last several years of evaluation they are simultaneously evaluated in large scale on farm trials as well as University Official Variety Tests (OVT's). Company grower cooperators manage Agronomic Service Trials (AST's) according to their typical management practices. D&PL has built a proprietary Agronomic Information System data base that contains both OVT and AST data and uses both sources of information for variety evaluation, positioning, and marketing. This manuscript will describe the degree of agreement between the two sources of information. The Mid-South and Southeastern states all have aggressive OVT testing programs, thus we concentrated our comparisons to these regions. Texas has aggressive but distinct OVT testing programs. Our goal was to avoid direct comparisons to individual state OVT's and to make the comparisons more geographically general. Hence, this manuscript will deal with comparisons where OVT results include two or more university programs. Variety least square mean values were established within a region as a percentage of the grand test mean for both OVT and AST data. The degree of agreement between variety performance over a four year period (1998 to 2001) ranged between R² = 0.67 to 0.76. Additionally, variety stability charts for standard varieties indicated both sources of data appeared to be from a common population.