不同生育阶段洪涝淹没时长对水稻生长发育及产量构成的影响

Effects of flooding duration in different growth stages on growth and yield component of rice

夏季小流域洪涝常常导致南方稻田受淹并成灾。为探究小流域洪涝淹没时长对水稻生长发育及产量的影响,于2015—2016年在广西象州县选用丝香1号和百香139进行双季稻淹水试验,分别设分蘖期、孕穗期和开花期淹没0(对照CK)、2、4、6、8、10 d处理,测定淹没前后的茎蘖数变化、抽穗期及收获后的每穗粒数、结实率、千粒质量和每盆稻谷产量,并对产量构成因素进行相关分析和通径分析。结果表明:与对照组相比,同一生育期内淹没时间越长茎蘖死亡率越高、植株恢复生长越慢,但不同的淹没时期影响程度和主要影响对象存在差异。分蘖期淹没超过6d则死苗率大于80%,且不能完全恢复生长,收获时水稻茎蘖数显著低于对照组;孕穗期淹没超过6d则死苗率大于50%,而淹没小于4 d的处理水稻能恢复生长,收获时水稻茎蘖高于对照组;开花期淹没10 d死苗率不足50%,收获时茎蘖数与对照组差异不显著。分蘖期淹没小于4 d水稻始穗期及抽穗持续时间均无显著变化,大于8 d则水稻始穗期显著推迟,抽穗持续时间增加;孕穗期受淹没则会使水稻始穗期推迟,抽穗持续时间显著增加,甚至收割时也未能达到齐穗期标准。分蘖期淹没小于4 d,单株产量无显著下降,淹没6 d及以上则减产率大于80%;孕穗期及开花期淹没超过2 d则减产率大于50%。不同生育期淹没处理下产量的主要因素不同,分蘖期主要受有效穗数和结实率影响,孕穗期受结实率及每穗粒数影响,开花期受结实率和有效穗数影响。研究可为建立西南地区双季稻洪涝灾害指标体系和提出减灾管理措施提供依据。

Flooding is one of main disasters affecting agricultural production in China.Its influence on rice is rarely studied in Guizhong District in Guangxi.In this study,we investigated the effect of different flooding duration in different growth on growth and yield component of rice.The experiment was carried out in Nalu Cun of Laibing City,Guangxi,China(109°52' E,24°4'N).The soil was sandy loam.Sixiang No.1 and Baixiang No.139 both as early and late rice were planted in pots in 2015 and 2016.Flooding of early rice started in different growth stages of tillering,booting and flowering.At each growth stage,flooding lasted for 0(control),2,4,6,8 and 10 days,respectively.Because the precipitation during the booting and flowering stages of late rice was small the flooding of late rice was designed at 3 different date in tillering stage.At flooding,the water surface remained 2-3 cm higher than plant height.Flooding duration of late rice was same as that of early rice.During the experiment,the tiller number before and after flooding,the heading stage time and its duration,grain number per panicle,seed setting rate,1000-grain weight and yield per pot after harvest were determined,and the relationships between yield and yield components were analyzed by path analysis.The results showed that the seedling death rate was less than 7.5%when the flooding duration at the tillering stage was below 2 days,not significantly different from control.As the flooding duration increased to 4-10 days,the death rate increased.When the flooding lasted for more than 6 days the death rate of early rice could reach more than 80%and even all the plants died.The death rate of Sixiang 1 reached 50%after flooding 6 days while it was still smaller than 50%for Baixiang 139 after flooding less than 10 days.The death rate was below 40%for the treatment of flooding at flowering stage.The initial heading stage time of flooding 8 d was postponed than that of control when flooding at different growth stages,and heading duration duration was also prolonged.The yield was not significantly decreased when the flooding at the tillering stage lasted for less than 4 days,but flooding for 6 days could result in the reduction of yield by 80%and flooding for 8-10 days could result in the death of plants.The yield reduction rate of flooding for 2 d at the booting and flowering stages was higher than 50%.The path analysis of yield component showed that the yield was mainly affected by effective panicle number,seed setting rate and 1000-grain weight for the flooding at the tillering stage,by seed setting rate,number of grain per panicle and 1000-grain weight for the flooding at the booting stage,and by effective panicle number and seed setting rate for the flooding at the flowering stage,respectively.The study provides important information for formulating flooding disaster warning system and management methods of dual-rice in Xinan region.