沿黄稻区水稻灌浆期遮阴对产量和品质的影响及耐弱光粳稻品种筛选

Effects of Shading on Yield and Quality of Japonica Rice Varieties in Rice-growing Regions alongside the Yellow River during Grain-filling Stage and Screening of Low-light Tolerance

水稻灌浆期经常遇到阴雨寡照天气,从而导致水稻减产和品质下降。本研究通过分析沿黄稻区近6年水稻灌浆期的气象数据发现,灌浆期日照时数减少是在该时期影响沿黄稻区水稻生产的主要气候因子;以生育期适合沿黄稻区种植的80个粳稻品种为材料,在灌浆期用65%的黑色遮阳网遮阴30 d,检测了水稻冠层顶部晴天、阴天和雨天3种天气下光、温度和湿度等生态环境,分析了灌浆期遮阴对水稻千粒重、加工品质和垩白性状的影响,并进行了耐弱光品种的筛选。结果表明遮阴后水稻冠层顶部阳光在能量和信号两个层面都发生了变化,即辐射量减少和R/FR比值降低;灌浆期遮阴后千粒重降低、糙米率、精米率和整精米率下降、垩白粒率和垩白度增加,其中对千粒重和垩白性状影响最大;以遮阴后千粒重降幅、垩白粒率和垩白度增幅为指标,通过聚类分析从中筛选出了方四落、新丰5号、早香3和小香共4个优质耐弱光品种。

Rice is often exposed to cloudy and rainy weather during grain filling,resulting in decrease in rice yield and quality.By analyzing the meteorological data of rice grain filling during the last 6 years(2012-2017)in rice-growing region alongside the Yellow River(RAYR),it was found that the decrease of sunshine duration during grain filling period was the main climatic factor affecting rice production.80 varieties of japonica rice from Japan and China were used for shading experiment,which created 65%reduction of full natural light making use of one layer of black netting and last 30 days during grain filling period.Light intensity,red light and far red light intensity,temperature and humidity in 3 weather conditions(sunny,cloudy and rainy)on the top of canopy were measured.And the 1000-grain weight,milling quality and chalkiness under shading were analyzed to screen shade tolerant japonica rice varieties.The results showed that in our study the temperature and humidity were no difference between shading and natural condition.The sunlight at the top of canopy was changed at two aspects,energy and signal,which indicated that radiation and R/FR ratio were both decreased under shading.1000-grain weight,brown,milled and head rice rates were decreased,and chalky rice rate and chalkiness degree increased under shading.Among these characteres 1000-grain weight and chalkness were mostly affected by shading.Based on 1000-grain weight decrease,chalky grain and chalkness degree increase under shading,4 high quality and shade tolerant japonica rice varieties were screened,which including Fangsiluo,Xinfeng5,Zhaoxiang3 and Xiaoxiang.Thus,these shade tolerant varieties with excellent grain quality served as valuable resource in future breeding for new resistant low-light varieties.