不同品种双季晚稻产量结构对干旱胁迫的响应

干旱是湖南双季晚稻分蘖-幼穗分化期主要农业气象灾害,对晚稻生长和产量形成产生不利影响。本研究以常规晚稻和超级晚稻在分蘖-幼穗分化期进行干旱胁迫试验,于20142016年连续3年开展15、20、25、30d4个干旱处理水平试验,探讨了干旱强度与不同品种双季晚稻产量结构的关系,从而确定双季晚稻干旱指标。试验研究结果表明,相同干旱胁迫处理下,土壤相对湿度是影响双季晚稻产量结构的关键因素,常规晚稻和超级晚稻产量结构对干旱胁迫的响应存在差异性。自晚稻分蘖普遍期开始干旱处理,对常规晚稻理论产量、有效穗数和结实粒数产生不利影响的土壤相对湿度阈值分别为92.5%、87.2%和98.6%;对超级晚稻理论产量、有效穗数和结实粒数产生不利影响的土壤相对湿度阈值分别为96.8%、97.1%和89.3%。根据晚稻产量结构对干旱持续时间和土壤湿度的响应,构建了常规晚稻和超级晚稻的分蘖-幼穗分化期干旱等级指标,可为双季晚稻的干旱监测和抗旱救灾提供理论依据和实践指导。

Research on Yield Structure of Different Varieties of Double cropping Late Rice Response to Drought Stress

Drought is the main agricultural meteorological disaster in tillering ear primordial stage of double cropping late rice in Hunan province,and has adverse effects on the growth and yield formation of late rice.This test researches on conventional late rice and super late rice under condition of simulating drought stress during tillering ear primordial stage,the duration of drought treatment is set 15,20,25 and 30 d respectively from 2014 to 2016.The relationship between drought intensity and yield structure of double cropping late rice is discussed,in order to determine the drought index of different varieties of double cropping late rice.The results show that under the same drought stress,relative soil moisture is the key factor that influences the yield components of the double cropping late rice.The response of different varieties of conventional late rice and super late rice to drought stress are different.Drought stress begin in tillering period,when theoretical yield,effective panicle number and solid grain number of conventional late rice are affected,threshold values of relative soil moisture are 92.5%,87.2% and 98.6% respectively,when theoretical yield,effective panicle number and solid grain number of super late rice are affected,threshold values of relative soil moisture are 96.8%,97.1% and 89.3% respectively.According to yield components response to drought duration and soil moisture,the conventional late rice and the super late rice drought grade index in tillering ear primordial stage are carried on.The test results provide an important theoretical basis and practical guide for drought monitoring,drought resistant and relievable of double cropping late rice.