两系亚种间杂交稻两优培九产量形成的生理特性

在高产栽培条件下,以汕优63为对照,研究两系亚种间杂交稻两优培九产量形成的生理特性.结果表明:(1)两优培九群体物质积累能力明显较强,尤其是抽穗至成熟期的群体干物质增量比汕优63高30.27%;群体叶面积指数大、叶质厚、功能期长、消光系数低、净同化率高是其物质高积累的综合生理基础.(2)两优培九源库比不低,单位库容可利用的同化物也不少,但群体干物质向经济器官的分配率较低,结实率、产量库充实率和收获指数明显下降,影响增产效果;其主要内在原因可能是,颖花或籽粒生理活性低,接纳灌浆物质的能力不强,致使大量同化物滞留于茎鞘和叶中,不能有效地向经济产量转化,这在育种和栽培中应加以重视.(3)两优培九结实期对源的削弱反应更强烈,这是亚种间杂交稻环境敏感性的一种生理表现,在大面积推广应用中,要加强技术指导以确保安全和稳定生产.

Physiological characteristics of yield formation in Liangyoupeijiu,a two-line intersubspecific hybrid rice

Under the high yield cultivating conditions, some physiological characteristics related to yield formation of a two line intersubspecific hybrid rice Liangyoupeijiu were studied with Shanyou 63 as a control. The results were as follows. (1) The dry matter production of Liangyoupeijiu was obviously higher than the control, especially during the heading to ripening period when the increment of dry matter accumulation in Liangyoupeijiu was 30.27% more than Shanyou 63. This high dry matter accumulation was based on such comprehensive physiological characteristics as large and thick leaves, long leaf duration, and high NAR. (2) The ratios of source/sink and the usable assimilation product per unit of sink were not low for Liangyoupeijiu, but its dry matter partitioning to spikelets was insufficient, resulting in lower rates of seed setting and sink filling, and causing lower harvest index, which influenced yield increasing. These results may be mainly owing to low physiological activity and filling ability of spikelets which made a large amount of assimilation products held up in and on stem, leaf and leaf sheath, and can′t transform to grains effectively. (3) Liangyoupeijiu was more sensitive than Shanyou 63 in response to source weakening at the filling period. This is a physiological characteristic for intersubspecific hybrid rice to behave with environment changes. So when it is applied to production by a large scale, technological guidance should be strengthened in order to make the production safer and steadier.