Analysis on Heterosis for Yield and Agronomic Traits of Hybrid Rice with Different Cytoplamsic Types

Ten male sterile lines(maintenance line) came from 6 cytoplasmic types and 10 restorer lines were used as parents to make 100 crosses by NCⅡ design to analyze heterosis of yield and others 7 agronomic characters.The results showed that the differences existed in over-parent and contrast heterosis among the hybrid combinations that crossed with the same male(or female)parent and different felame or male restore lines on the same trait among different hybrid combinations and on the same hybrid combination among different traits.Strong positive over-parent and contrast heterorsis existed on grain number per panicle and panicle length,and strong positive contrast heterosis existed on seed setting rate,while over-parent and contrast heterosis on others traits were weak.Among 6 cytoplasmic types,the over-parent and contrast heterosis were strongest in hybrid combinations with G-type and D-type cytoplasm.Among 10 restore lines,over-parent heterosis of combinations from R388 and Miyang 46 were strongest,while contrast heterosis of combinations from Minghui 63 and R478 were stronger.The effect of restorer lines on over-parent and contrast heterosis of combination in most traits was bigger than cytoplasmic type.