杂种小麦开花后生物产量及其组分的动态变化

试验以化杀杂种CH－1和不育系杂种VH－2及其亲本为材料，比较研究了杂种小麦开花后生物产量及其组分的动态变化，结果表明：（1）杂种小麦开花后的营养体于重量大，籽粒的增长速率高，增量大，收获指数高，生物产量具有较强的杂种优势。杂种的粒重超双亲平均值（MP）9．5％－18．7％，超对照（CK）15．8％；（2）不同器官的干重变化有别。CH－1与其双亲平均值（MP1）和对照（CK）比，中上部器官倒1－3节茎鞘叶中的光合产物输出的多，失重大，对籽粒的贡献大，而中下部器官倒4节下茎鞘叶中的光合产物输出的少，失重小，物质积累的多，不育系杂种VH－2营养体干重的变化规律同CH－1，但器官失重少，与其双亲平均值（MP2）和CK相比，虽然生物产量高，但器官干重于减少量低，收获指数小，究其原因主要是不育系杂种结实率低（88％－94％），器官中光合产物输出少，积累多，使库源关系不协调所致；（3）营养体干重与籽粒重呈现显著正相关关系（r=0.8728^**)，而杂种的粒重优势恰是体现在营养体干重的优势上，因此，通过增加营养重量，进而增加粒重，提高产量，是协调和提高杂种小麦生物产量和收获指数的关键所在。

Dynamic changes of biomass yield and its components after anthesis in hybrid wheat

CHA hybrid CH 1 and CMS hybrid VH 2 as their parents were planted,the dynamic changes of biomass yield and its components after anthesis were analysed.The results showed that (1) After anthesis,hybrids had more vegetative mass dry weight and higher grain increasing rate and larger grain increment,and demonstrated stronger heterosis on biomass,surpassing mean of parents (MP) at 9.5%~18.7% and the control (CK) at 15.8%.(2) Different organs had different changes in dry weight.Compared with MP 1 and CK,the first to third stems and sheathes from top in CH 1 exported more photosynthate and made more contribution to the grains,while the forth and the below stems,sheathes and leaves from the top exported less photosynthate and accumulated more dry matter.Compared with CH 1,CMS hybrid VH 2 showed same regulation in vegetative mass dry weight,it losses a little that the dry weight of organs,compared with its MP 2 and CK,though the biomass of VH 2 was higher,it had lower reduce amount in organic dry weight.We considered that the key reason was that CMS hybrid VH 2 had lower seed setting rate (88%~94%),so the photosynthate in their organs exported less and accumulated more which caused the lacking of harmony between sink and source,and the low seed setting rate was one of key factors made VH 2 have lower harvest index.(3) The dry weight of vegetative mass had a significantly positive correlation with grain weight ( r =0.8728 ** ),while the heterosis of vegetative mass dry weight was the expression of the heterosis of grain weight in hybrids.So the way to increase vegetative weight and grain weight,raise yield was a key method to harmony and enhance the biomass and harvest index of hybrid wheats.