Dynamics of water retaining capacity and chlorophyll content of two-line hybrid rice during heading-grain filling stage and their relations with grain yield
两系法杂交水稻抽穗结实期持水量和叶绿素含量的动态变化及其与籽粒产量关系研究

The study with 25 two-line hybrid rice strains showed that their water retaining capacity was different with their combinations.On the whole,the water content in leaf and stem-sheath decreased during heading-grain filling stage,while that in panicle increased first and then decreased,with a peak at 7th day after heading.Stem-sheath was the main organ for water retaining.The correlation of panicle yield with both leaf and stem-sheath water content was positive at the 1st day after heading but became negative later,and that with whole stem-plant water content was positive after heading.The chlorophyll content of the two-line hybrids increased first and then decreased,with a peak at the 7th day after heading.Comparing with normal rice (male parent),the chlorophyll content of most two-line hybrids was lower,and the decreasing rate was faster than that of normal rice after heading.For two-line hybrid rice breeding,it should preferentially consider to select those hybrids which have a clearer dominance of plant water retaining capacity and a higher chlorophyll content at earlier and middle heading-grain filling stage,and an obvious dry matter transportation from leaf and stem-sheath at later heading-grain filling stage.For two-line hybrid rice planting,it should not only pay attention to the supply of water and nutrients,especially nitrogen at earlier and middle heading-grain filling stage,but also control nitrogen and water in time to prevent leaf green clinging and to promote dry matter transportation from leaf and stem-sheath to grain at later heading-grain filling stage.