Inheritance of water use efficiency in diallel hybrids of spring barley under varied nutrition and soil moisture
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Inheritance of water use efficiency (WUE) at the whole-plant level was investigated in a diallel set (Ps+F2s) of spring barley. Plants were grown in 9 dm3 pots under optimal conditions, low NPK nutrition and low soil moisture. GCA effects were found to be of major importance for the variance in vegetative and economic WUE measures. A significance of SCA effects was observed only under nutrient and soil moisture stresses. The stress conditions used did not considerably affect the sign and magnitude of combining ability effects. Consistency between GCA and parental means was found. The efficiency of water use under stress did not correlate with stress tolerance indices, but stress-induced changes in the harvest index and WUE were closely related to the tolerance. An analysis of genetic components of variation indicated that additive gene effects were of major importance for the vegetative and economic WUE measures. Moderately high narrow-sense heritabilities of WUE under optimal conditions (0.64-0.69) were found to decrease to 0.46-0.53 and 0.13-0.35 under limited fertilization and simulated drought, respectively. Partial dominance of genes was observed. The degree of dominance of genes was found to increase under stress. The results suggest that a low WUE is a recessive character. It is supposed that the preponderance of additive gene effects should facilitate selection efforts to improve WUE in spring barley.
Publication order reference
A.G. Gorny, Institute of Plant Genetics, Polish Academy of Sciences, ul. Strzeszynska 34, 60-479 Poznan, Poland, E-mail: email@example.com