Abstract:

To clarify the genetic correlation and breeding application value among grain yield, biological yield and harvest index of wheat, this study systematically analyzed the relationships among grain yield, biological yield, and harvest index, as well as their genetic variation characteristics, using 30 stable inherited wheat lines. The results showed extremely significant differences among lines for biological yield, grain yield, and harvest index, with variation ranges of 8.79-13.4 g, 4.35-5.90 g, and 0.407-0.539, respectively. Coefficient of variation (CV) analysis revealed the highest genetic variability in biological yield (CV=11.7%), whereas that in harvest index was relatively stable (CV=6.9%). Correlation analysis indicated a highly significant positive correlation between grain yield and biological yield (r=0.7904), indicating that increasing biological yield was the key to promoting grain yield growth. However, there was a highly significant negative correlation between biological yield and harvest index (r=-0.6949), reflecting the inherent trade-off between them. In conclusion, enhancing biological yield with synergistically optimizing harvest index is proposed as an effective strategy for future ultra-high-yield wheat breeding, under the current challenge of limited gains in harvest index. These findings provide a direct theoretical basis and practical guidance for breeders to precisely select lines with coordinated source-sink relationships and efficient assimilate partitioning, thereby holding significant value for shortening the breeding cycle and improving selection efficiency.

Key words: wheat, grain yield, biological yield, harvest index