Combining ability for crude protein in six selected inbred x Triticosecale genotype

[摘要] English: The objective of this study was to study the combining ability, heritability and additivegenetic correlation of various crude protein characteristics in a selected fixedpopulation.Three treatments were used to obtain grain production. The control treatment was leftuncut; the cut 1 treatment had one cut of vegetative material before left for grainproduction while the cut (1+2) treatment had two consecutive cuts before the plantswere allowed to produce grain.Characters measured for grain in all treatments were grain yield, percentage crudeprotein and crude protein yield. Characters measured for the vegetative materialwere percentage crude protein and crude protein yield. The total herbivore utilisablecrude protein yield where the total crude protein yield of the vegetative material wascombined with the grain crude protein yield of the cut (1+2) was also determined.Highly significant differences were shown between both genotypes and treatmentsfor vegetative and grain characters when the phenotypic means of parents andoffspring were evaluated in factorial analyses.The F1 progeny of a 6 x 6 half diallel cross were evaluated in the combining abilityanalyses using the Method 4, mixed model B analysis of Griffing (1956b), becauseonly one reading per plot was obtainable for each of the characteristics measured.In the combining ability analyses of the F1 progeny, highly significant and significantdifferences were shown for gca effects and sca effects respectively when vegetativecrude protein yield was evaluated in the cut 1 treatment. The σ2gca/σ2sca ratio differedbetween treatments and was higher for vegetative crude protein yield in the cut 1treatment than in the cut (1+2) treatment.No significant differences between gca effects or sca effects could be found for grainyield or grain crude protein yield in the analyses of variance for any of the treatments.A significant difference between gca effects was shown for the combinationcharacter, total herbivore utilisable crude protein yield.With the aim of evaluating the combining ability effects to select parents for a betterdual purpose triticale cultivar and to identify possible good hybrid combinations inmind, selections could be made with the available data of the cut 1 treatment asbasis.When the variance components, heritabilities and correlated responses werecalculated, the decision to base selection on the vegetative crude protein yield of thecut 1 treatment was confirmed. This character showed highly significant additivegenetic correlations with both the total vegetative crude protein yield and the totalherbivore utilisable crude protein yield.

[发布机构] University of the Free State