Heterosis and Combining Ability for Major Yield Traits of a New Wheat Germplasm Shannong 0095 Derived from Thinopyrum intermedium

The wheatgrass,Thinopyrum intermedium (Host) Barkworth & DR Dewey,shows many beneficial characteristics,such as big spikes and high resistance to many diseases.To transfer the benefi.cial genes of this species,many wheat Thinopyrum intermedium alien chromosome lines were developed.Of them,Shannong 0095 (SN0095),a disomic substitution,has long spikes and flag-leaves,and thus may be an important genetic resource for wheat yield improvement.In order to realize its heterosis and combining ability on major yield traits,a 7 × 7 complete diallel design was made according to Griffing's Method-I.The results showed that heterosis for spike length (SPL),flag-leaf area (FLA),number of spikes per plant (NSP),number of spikelets per spike (NSL),kernels per spike (KPS),1 000-kernel weight (TKW) and grain yield per plant (GYP) existed in all the crosses by SN0095,but heterobeitiosis occurred only for KPS,TKW,and GYP.The relative mid-parent heterosis (RMH) and relative high-parent heterosis (RHH) for GYP,which valued as high as 35.32and 29.92% respectively,were the highest among all the traits mearsured.Though additive and non-additive gene effects and cytoplasmic effects (or cytoplasmic-nuclear interaction effects) were found in governing all the traits measured above,additive gene action played a predominant role.The results also showed that SN0095 was the best-general combiner for SPL and FLA,and high-general combiner for NSP amongst all the parents.Estimates of specific combining ability (SCA) showed that SN0095 could also make high-SCA combinations for GYP,such as SN0095 × Jimai 19 (JM19).SN0095 could be a unique and important parent in hybrid wheat breeding programs.