Effect of cold stress on boro rice seedlings

Abstract

Cold stress at seedling stage is a major constraint in boro rice production. Nine boro rice lines were crossed in diallel fashion excluding reciprocals to obtain 36 crosses. All the 36 crosses along with parents were grown in nursery in three seasons (boro-2014, kharif-2015 and boro-2015). Performance of seedlings for survival per cent, chlorophyll content, relative water content, membrane stability index was recorded just before transplanting in all the three seasons. Scoring for cold tolerance was done in both boro seasons. Gautam showed highest survival rate over three seasons. Among crosses, IR 64 x Krishna Hamsa showed highest survival (84%) in boro-2014, MTU 1010 x Jaya (86.33%) in boro-2015 and MTU 1010 x Krishna Hamsa (95.67%) in kharif-2015. Jaya x Krishna Hamsa was most cold tolerant cross over both boro seasons. Significant positive correlation was observed among survival per cent, chlorophyll content, relative water content and membrane stability index over seasons.