Multi-Year Analysis of Breeding for No-till Systems in the Mid-Atlantic Region.

The Virginia Tech soybean breeding program has been targeting adaptation to no-till, double-crop production systems for over 10 years. Breeding objectives include increased yield and earlier maturity in conventional, herbicide tolerant, and food-grade germplasm. State variety trials data suggest this has produced superior germplasm adapted to no-till systems. We present methods for testing under no-till systems and a multi-year analysis of genotype x environment interactions in no-till double-crop versus conventional-till full-season yield tests. We determined from a two-year study designed to measure G x E for yield and quality traits under different cropping systems that the different systems have a significant effect on selections, but the magnitude of the impact does not justify selecting cultivars targeted specifically for no-till double crop systems. Historical efforts and other experiences support this conclusion.