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

对25个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的研究表明,杂种水分持有量变化存在因组合不同而异的特点,总体上叶片和茎鞘水分持有量抽穗结实期间表现为下降趋势,穗部水分持有量表现为先升后降的特点,以抽穗后第7d,即籽粒灌浆高峰期最大;叶、茎鞘部水分持有量所占比例呈下降趋势,穗部所占比例则一直呈上升趋势,茎鞘部始终是水分的主要贮存场所;单茎植株水分总持有量抽穗后第1天多数组合表现为正向父本优势,尔后多转为负向父本优势;籽粒产量与抽穗后各期片水分持有量呈正相关,与抽穗后第1d茎鞘水分持有量呈正相关,自第7d始转为弱负相关,与抽穗后穗部水分持有量呈正相关,与抽穗后单茎植株水分总持有量呈正相关,籽粒产量与水分持有量在各器官中分配的相关和籽粒产量与各器官水分持有量的相关趋势总体一致;两系杂交稻叶绿素含量表现为先升后降的特点,以抽穗后第7天最高,与常规稻父本相比,两系杂交稻叶绿素含量各期大多数组合低于常规稻父本,且下降速度快于常规稻父本.对于两系法杂交水稻,育种上应优先考虑选择灌浆前、中期植株水分持量优势较强、叶绿素含量较高、后期茎叶物质转运优势明显的组合;栽培上应注意保证灌浆前、中期水分及营养元素,特别是氮素的供应,还要注意后期的及时控氮脱水防贪青,促进茎叶贮存物质向籽粒运转.

Dynamics of water retaining capacity and chlorophyll content of two-line hybrid rice during heading-grain filling stage and their relations with grain yield

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.