Estimating the relative effects of the endosperm traits of waxy and high protein digestibility on yield in grain sorghum

Sorghum (Sorghum bicolor L Moench) is an important crop that is widely grown in dry climates across the world. The grain is used for food, feed and industrial purposes and the quality of the grain influences the relative utility for each specific use. In sorghum grain, both the waxy endosperm and the high protein digestibility traits have the potential to significantly alter conversion efficiencies of sorghum in several applications including production of grain ethanol and brewing. There are concerns though, that these traits may confer a reduction in the agronomic and yield performance of lines and hybrids that possess them. The objective of this study was to assess the potential impact of both the waxy and the high digestibility traits on the yield of grain sorghum lines. From an F-2 breeding population segregating for both waxy and highly digestible endosperm, 100 F-2:4 lines were derived, with equal number in each of four categories: high digestible (HD), waxy (WX), HD and waxy (HD-WX), and normal. No selection for yield was practiced during the development of these lines. The lines and checks were evaluated in two environments in Texas. Across all environments, there was no significant difference between yields. In addition, analysis by genotype revealed that several WX, HD-WX, and HD lines were among the best yielding lines. These results imply that selection of high yielding WX and HD genotypes is possible, but a significant breeding emphasis on their development and selection is required to effectively identify those genotypes. (C) 2012 Elsevier B.V. All rights reserved.