Study of seed maturity and storage longevity in three sorghum cultivars uri icon

abstract

  • An experiment was conducted in Patancheru, Andhra Pradesh, India, to study the changes in seed quality during ripening and determine the optimum harvest time to maximize potential longevity during regeneration of sorghum cultivars IS 11758, IS 18758 and IS 19907. The potential longevity of the seeds harvested between 28 and 70 days after anthesis (DAA) in IS 19907 and between 28 and 77 DAA in IS 17758 and IS 18758 was studied by storing the seeds at 35°C with 13±0.2% moisture content. IS 19907 was the earliest to flower at 50 days after sowing, followed by IS 18758 at 60 days and IS 11758 at 71 days after sowing. In all the cultivars, the seed dry weight rapidly increased from 7 DAA until it reached maximum at approximately 35 days. The estimates of mass maturity were 34.3 days for IS 19907, 38.5 days for IS 18758 and 40.8 days for IS 11758, with a mean of 37.9±1.90. At mass maturity, the seed moisture content ranged between 36.6 and 33.2% among the 3 cultivars with a mean of 34.8±0.97%. In all the cultivars, fresh seeds harvested at 7 DAA did not germinate. However, germinability increased from 14 DAA and reached maximum by 28 DAA in IS 18758 and IS 19907, and 42 DAA in IS 11757. All the seed lots gradually deteriorated during storage at 35°C, while differences were observed in the rate of loss of viability among the seed lots harvested at different maturity stages within each cultivar. Potential longevity increased between 28 and 70 DAA depending on the cultivar and decreased slightly in later stages of maturity. The differences in potential longevity were marginal for the seeds harvested between 56 and 70 DAA in IS 19907 and between 63 and 77 DAA in IS 11758 and 18758. The maximum potential longevity was attained at 66 DAA in IS 19907, 74 DAA in IS 11758 and 76 DAA in IS 18758, with a mean time of 72.0±3.06 DAA, which was approximately 35 days after the mean mass maturity. The mean moisture content at this stage ranged between 7 and 9% among the cultivars. The mean maximum and minimum temperatures from sowing to the last harvest date were 30.8 and 14.5°C, respectively. The cumulative thermal day degrees or thermal time from anthesis to mass maturity was between 343 and 437°Cd (mean = 388±27.2) and thermal time from mass maturity to storage maturity ranged from 359 to 452°Cd (mean = 414±28.1°Cd) between the 3 cultivars. Averaged over cultivars, the mean thermal time from anthesis to storage maturity was 802±50.6°Cd

publication date

  • 2007