Potential Gain from Selection in Grain Sorghum for Higher Protein Digestibility
- P. J. Bramel-Cox ,
- M. A. Lauver and
- M. E. Witt
Grain sorghum [Sorghum bicolor (L.) Moench] has not been fully utilized as a feed grain because of its highly variable feeding quality, which has been related to factors such as various grain characteristics that relate to the availability and quality of the protein and starch, response to environmental conditions, and processing methods in feed preparation. The objective of this study was to evaluate the potential to genetically improve the feeding value of grain sorghum through improved protein digestibility in a random-mated population of grain sorghum. The study consisted of a 2-yr and 5-location evaluation of 100 S1 families in a blocks-in-replication design for grain yield, protein concentration, protein digestibility, and bloom date. The phenotypic and genotypic correlations indicated there was a negative association between grain yield and maturity but a positive association between protein digestibility and maturity resulted in a dramatic undesirable shift in the population to later maturity. Selection for grain yield resulted in families with earlier maturity and reduced protein digestibility, thus, selection for any single trait did not identify high yielding high protein-digestible families with an acceptable range of bloom date. Using a rank summation index, calculated as Rank (grain yield) + Rank (protein digestibility) — Rank (bloom date), and restricting selection to the families rated in the top 50% for yield and protein digestibility increased both traits without an undesirable change in bloom date.
Copyright © 1990.