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Studies on Premature Heading and Its Prevent Methods for Early Season Culture and Planting of Extremely Early Rice Cultivars in Warm South-west Japan

温暖的西南部地区极早稻品种早抽穗及其防治方法的研究

基本信息

批准号：
14560012
负责人：
YAMAMOTO Yoshinori
金额：
$ 2.37万
依托单位：
Kochi University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

项目摘要

The premature heading of ‘Tosapika', an extremely early rice cultivar bred in Kochi Prefecture occurred in many farmer's fields in the first year of planting (1988). This study was conducted to clarify the factors related to premature heading of the cultivar ‘Tosapika', and to establish a method of cultivation that would prevent premature heading.1.The effective cumulative temperature (base temp. 10℃) after sowing to flag leaf expansion was lower in ‘Tosapika' due to the fewer number of final leaves on the main culm in comparison with the cultivars bred in Hokkaido. The panicle differentiation and development was scarcely influenced by daylength in the seedling of ‘Tosapika' and the panicle formation stage was observed at 301-348℃ days from sowing. These results were suggested that the thermo- and photo-sensitivities and basic vegetative growth of ‘Tosapika' were comparatively small.2.Yield in the premature-heading group (PMHG) was 9-15% lower than that in the control group (CG). In the PMHG the number of spikelets per unit area was lower than in the CG, due to the markedly lower number of spikelets per panicle. The decrease in the number of spikelets, together with the lower percentage of filled grains on the tillers, was considered to be the reason for the lower yield in the PMHG. The apparent quality of the brown rice was low in the PMHG because of the presence of a lot of green rice kernels.3.As the methods of cultivation that would retard premature heading of ‘Tosapika', it was suggested that nursery management such as not topdressing nitrogen after 200℃days from sowing (after 3.5 leaf age) and higher sowing rates for the lowering dry weight/plant height ratio were necessary to retard young panicle differentiation in ‘Tosapika' seedlings as well as an increased basal nitrogen application for the nursery box and leaf cutting treatment during nursery period.

在高知县培育的极早熟水稻品种‘Tosapika’在种植的第一年（1988年）在许多农民的田地里发生了过早抽穗。本研究旨在阐明影响‘土佐比香’早抽穗的相关因素，并建立防止早抽穗的栽培措施。与北海道育成的品种相比，“Tosapika”在播种后至剑叶展开的最低温度（10℃）下，主茎末叶数较少。“Tosapika”苗期穗分化发育受日照影响较小，穗形成期为播后301-348℃。这些结果表明，“Tosapika”的温敏性、光敏性和基本营养生长都较小。2.早熟抽穗组（PMHG）比对照组（CG）减产9-15%。在PMHG的单位面积的小穗数低于CG，由于显着降低每穗的小穗数。水稻分蘖成穗率低、小穗数少是造成产量低的主要原因。3.作为延缓‘土佐碧香’抽穗的栽培措施，建议在播种后200℃后不追施氮肥等苗圃管理措施（3.5叶龄后）和较高的播种量降低干重/株高比是延缓‘Tosapika’幼苗幼穗分化的必要条件，同时也需要增加育苗箱和叶片的基施氮量育苗期扦插处理。