Effect of Seedling Age on-the Flowering Behaviour in Hybrid Rice Seed Production

摘要

The transplanting of 20, 25, 30, 35, 40 and 45 days old seedlings indicated that young seedlings were late to achieve 50 per cent flowering, where as older seedlings were early as compared to the standard, 30 days old seedlings. In case of CMS lines the young seedlings (20 days old) were late by 4 to 12 days for different genotypes under two environments in comparison to 30 days old seedlings. However, older seedlings (45 days) were early by 3 to 11 days for different genotypes. More panicle exsertion can be obtained if young seedlings are transplanted. This trait seemed to be effected by environments. The CMS line IR 58025A initiated panicle primordia 10 days earlier than other CMS lines, if the age of seedlings was 30 days or less. However, this line performed at par with other lines if aged seedlings were transplanted. Whereas, IR 58025B line was 5 to 15 days earlier than the other maintainer lines. It was observed that all the maintainer lines were almost 5 days earlier for panicle primordia initiation than their corresponding CMS lines. The restorerline P 218 initiated panicle primordia almost 20 days late than the other lines except for IR 31432, which performed at a par with various ages of seedlings.