Yield and stability factors associated with hybrid wheat

Abstract

For hybrid wheat to be accepted in the Great Plains of the USA, hybrids must exhibit enhanced yield performance, yield responsiveness, and reasonable yield stability across a wide array of production environments. Agripro has been researching hybrid wheat since 1981 and has an established pureline release history since 1978. Yield data from 1991 to 1995 were examined to compare the trend performance and selection gains of purelines and hybrids in a large scale parallel development effort. This data set (13,739 points) reveals an average 0.454 t ha^-1 or 10.8% hybrid yield advantage over purelines in preliminary regional testing. Entries selected from the preliminary trials show a greater hybrid advantage of 0.652 t ha^-1, or 13.5%. Several factors including enhanced stability over strong yearly environmental effects, improved agronomic and epidemiological expression through complementary inbred trait selection, and improved heat tolerance are likely contributors to this significantly improved selection gain. Yield stability of hybrids and purelines was compared in Agripro Standard Variety Trials and USDA-ARS Southern Regional Performance Nurseries from 1990 to 1995. In addition to having higher means than purelines, hybrid yield advantage increased with improving production conditions. The enhanced responsiveness of hybrids, as indicated by higher slopes in regression analyses, was combined with similar deviations from regression response. Hybrid wheat in the Great Plains of the USA has shown a fundamental yield, responsiveness and selection gain advantage over pureline varieties that could result in acceptance by producers.