Genetic relationships between grain yield and yield components in a synthetic maize population and their implications in selection.

摘要

The synthetic maize population 316PO2 (developed from 15 inbred lines) was subjected to genetic correlation analyses between grain yield and 9 morphological traits. The purpose was to enable estimates to be made of the advantage of using selection indices compared with selection based on grain yield only, and if that advantage was present, to choose enough simple selection indices for practical use. Selection indices were constructed out of all 4 traits highly significantly correlated with grain yield, in addition to yield itself. Grain yield exhibited a highly significant additive genetic correlation with ear diameter, kernels per row, ears per plant and ear height. The most efficient index was Index No. 14 (R.E.I12345=108.83%), which included all 4 traits and grain yield. Index No. 3, one of the simplest forms of index, including only ears per plant and grain yield, showed slightly less relative efficiency (R.E.I35=107.24%) than Index No. 14. Using this simple form of index with 2 traits (IndexNo. 3) could improve the efficiency of selection for grain yield. The estimated advantage from its use was 179.6 kg/selection cycle for grain yield over selection based only on grain yield. Thus, Index No. 3 is now being used in a recurrent selection programme in the studied population for the simultaneous improvement of grain yield and prolificacy.