Over 175 growers in each of six states (Illinois, Indiana, Iowa, Mississippi, Nebraska, and North Carolina) were surveyed by telephone to assess their perceptions of the benefits of utilizing the glyphosate-resistant (GR) crop trait in corn, cotton, and soybean. The survey was also used to determine the weed management challenges growers were facing after using this trait for a minimum of 4 yr. This survey allowed the development of baseline information on how weed management and crop production practices have changed since the introduction of the trait. It provided useful information on common weed management issues that should be addressed through applied research and extension efforts. The survey also allowed an assessment of the perceived levels of concern among growers about glyphosate resistance in weeds and whether they believed they had experienced glyphosate resistance on their farms. Across the six states surveyed, producers reported 38, 97, and 96% of their corn, cotton, and soybean hectarage planted in a GR cultivar. The most widely adopted GR cropping system was a GR soybean/non-GR crop rotation system; second most common was a GR soybean/GR corn crop rotation system. The non-GR crop component varied widely, with the most common crops being non-GR corn or rice. A large range in farm size for the respondents was observed, with North Carolina having the smallest farms in all three crops. A large majority of corn and soybean growers reported using some type of crop rotation system, whereas very few cotton growers rotated out of cotton. Overall, rotations were much more common in Midwestern states than in Southern states. This is important information as weed scientists assist growers in developing and using best management practices to minimize the development of glyphosate resistance.

Genes that affect plant form and function may be used to enhance the yield of soybean [Glycine max (L.) Merr.]. Most soybean cultivars have broad (ovate) leaflets. A single gene, ln, controls inheritance for the narrow leaflet characteristic. Narrow leaflet cultivars (ln/ln) also tend to have a higher percentage of four-seeded pods than ovate (Ln/Ln) leaflet cultivars. Heterozygous (Ln/ln) plants have a leaflet shape intermediate between narrow and ovate. Determining the agronomic effects of the narrow leaflet allele (ln) in the heterozygous (Ln/ln) condition in soybean may have applications in practical plant breeding. We studied an ovate leaflet and a narrow leaflet cultivar, crosses between them in the F(1) and F(2), and backcrosses to both cultivars. The ratio of leaflet width to leaflet length accurately distinguished among narrow, ovate, and intermediate leaflet plants in the F(2) and backcross generations. In the F(2) generation, differences occurred among plants with different leaflet morphology. Narrow leaflet plants produced more seeds per pod and lower seed weight than ovate leaflet plants. Narrow and ovate leaflet plants produced comparable numbers of pods per plant and plant yield. Compared to ovate leaflet plants, intermediate leaflet plants produced similar numbers of seeds per pod and seed weight. Intermediate leaflet plants produced significantly more pods per plant and plant yield than plants with either ovate or narrow leaflets. The heterozygous condition at the locus for leaflet morphology resulted in heterosis for plant yield and may be of benefit in association with commercialization and development of hybrid soybean.

Economic returns for cropping systems represent important management decisions for growers to consider in addition to agronomic practices. This study was conducted to determine the economic consequences of six soybean [Glycine max. (L.) Merr.] ‐ wheat [Triticum aestivum (L.)] cropping patterns. These patterns included monocrop soybean in 15‐ and 30‐inch rows, double‐crop soybean‐wheat in 15‐ and 30‐inch rows, and a modified double‐crop system with soybean in 15‐ and 30‐inch rows. An economic analysis of the six systems was conducted to compare net returns to land, labor, and management. The study was conducted at Bixby and Haskell, OK. The study was separated into three periods: Period 1 = 1992 and 1993; Period 2 = 1994 and 1995; and Period 3 = 1996 and 1997. Separation was necessary since the modified double‐crop system required a two‐year period to complete one cycle. The modified double‐crop system using a 15‐inch row spacing produced the greatest net return in each period at Bixby ($308, $306, and $244 per acre per year in Periods 1, 2, and 3, respectively) and the greatest net return at Haskell in Period 1 ($425/acre). Over the three periods and for both locations, the modified double‐crop system using a 15‐inch row spacing produced the greatest average net return per period of $310/acre. The modified double‐crop system using a 30‐inch row spacing produced the second highest average net return of $277/acre. This system produced $235/acre per period net return at Bixby and $320/acre per period net return at Haskell. The monocrop system produced an average overall net return of $299/acre with a 30‐inch row spacing. The double‐cropping system using a 15‐inch row spacing produced an average of $228/acre and the double‐cropping system using a 30‐inch row spacing produced an average of $226/acre in net return. The lowest overall average net return was produced by the monocrop soybean system using the 15‐inch row spacing with an average net return of $214/acre. Knowledge of economic returns from alternative cropping systems provide growers another tool in managing crop production.

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