Relationship of the Testa to Agronomic and Nutritional Traits in Sorghum1
- K. D. Kofoid,
- J. W. Maranville and
- W. M. Ross2
The testa layer of sorghum [Sorghum bicolor (L.) Moench] seed plays an important role in the digestion and assimilation of grain protein and amino acids. We studied the relationship of the testa character to agronomic and nutritional traits (including two minerals) in S1 families from two random-mating populations, NP13R (diverse germplasm) and NP14B (narrow base), where each was divided into subpopulations with and without a testa layer. In 1976, 200 families from each subpopulation were tested, and in 1977, 160 families from each were used.
Differences occurred between the testa and nontesta subpopulations in at least one population in at least 1 year for all of the traits studied except grain yield and height. The testa types tended to have lower means for other agronomic traits, although differences were not always significant. Among the nutritional and mineral traits, the testa types had more protein, lysine percent sample, K, and tannin; and less lysine percent protein, oil, carbohydrate, P, gross energy, enzyme (α-amylase) activity, in vitro dry matter digestibility, and metabolizable energy than the nontesta types. However, the results were highly influenced by the environment.
Correlations among traits were similar, with the exception of correlations involving tannin and enzyme activity, in each subpopulation. Tannin and enzyme activity were correlated with the other traits at similar magnitudes but of opposite sign when comparisons were made between the testa and nontesta subpopulations within each population.
Comparisons of mean values and the correlations of tannin and enzyme activity with the other traits indicated that the nontesta genotypes did not contain any astringent polyphenols although variable amounts of phenolic compounds were measured. Among the testa genotypes, astringent polyphenols were found in some S1 families but not others. Their tannin level and inhibitory effect on amylase activity were variable and greatly influenced by environment.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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