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QUANTITATIVE GENETICS OF NUTRITIONAL AND AGRONOMIC CHARACTERS IN RELATED GRAIN SORGHUM RANDOM-MATING POPULATIONS
Abstract
The relationships between nutritional traits and grain yield were studied biometrically in NP20BR, a broad-base grain sorghum {Sorghum bicolor (L.) Moench} population with superior quality attributes. Two related populations, NP20BR(MEC1) and NP20BR(MEYLDC1), tracing to the same base were developed with different objectives. The primary objective of this study was to investigate the applicability of mass selection in improving the nutritional value and yield of sorghum populations. The results indicate that improvements in nutritional traits have been accomplished through mass selection. Realized gains averaged over the cycle-one populations as percentages of the base mean were 16.84 for protein, 27.37 for oil, 11.73 for in vitro dry matter digestibility, 1.61 for gross energy, and 13.49 for metabolizable energy. Yield was reduced in both cycle-one populations as consequence of quality improvement. Estimates of genetic variance from testing 200 S(,1) families from each referenced population revealed small amount of variation for most nutritional traits but tremendous variability for most agronomic traits. Genetic variances increased for most traits after selection. Broad-sense heritabilities from the variance components of S(,1) families were relatively high for most nutritional and yield-related traits and were much larger than the estimates obtained from parent-offspring regression. Based on genetic parameters, NP20BR(MEC1) was inferior for most nutritional traits but superior for yield and yield-related traits compared with NP20BR(MEYLDC1). Predicted gains from a cycle of S(,1) family selection ranged from 12 to 19% of the means for yield and all production traits, and less than 8% of the means were predicted for all nutritional traits. The genetic correlations of yield and all yield-related traits with most nutritional traits were negative; however, most nutritional traits were positively correlated with each other. Direct selection for yield or quality alone will not result in simultaneous improvement of yield and quality traits. It is suggested that selecting for high metabolizable energy yield can be expected to improve yield equivalent to direct selection for yield alone without drastic reductions in quality.
Subject Area
Agronomy
Recommended Citation
FLORES, CATALINO ILLESCAS, "QUANTITATIVE GENETICS OF NUTRITIONAL AND AGRONOMIC CHARACTERS IN RELATED GRAIN SORGHUM RANDOM-MATING POPULATIONS" (1983). ETD collection for University of Nebraska-Lincoln. AAI8404826.
https://digitalcommons.unl.edu/dissertations/AAI8404826