Maize Research Institute, Shandong Academy of Agricultural Sciences
The results of the evaluating experiments showed that average plant heights of improved Pob.68QPM and Pob.70QPM were reduced by 42.0% and 45.0%, 15.2 cm and 16.3 cm per cycle. Times to silk (numbers of day from planting to 50% extruded silks) were decreased 9 d and 10 d, 1.5 d and 1.7 d per cycle. The harvest indices of improved maize materials had increased from about 30% to 45% and 47%, with average grain yield at optimum planting densities increased from about 1800 kg/ha and 2400 kg/ha to 2625 kg/ha (45.8%) and 3588 kg/ha (49.5%) respectively.
In addition to selecting for time to
silk, shorter plants to improve adaptability, we have selected for other
characters such as reduced tassel size (number of branches). Over the six
cycles of selection in these two populations, the results showed that tassel
size reduced as grain yields and harvest index were increased significantly.
The study also demonstrated the negative correlation between smaller tassel
and grain yield, but the high correlation between shorter plant height
and time to silk.
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