Effects Of Seed Storage And Packing Conditions On Seed Vigor And Its Attributes Of Hybrid Rice Seeds

The present study was designed to study the effects of storage conditions on hybrid rice seeds of cultivars i.e.Y Liang you 689(two-line indica hybrid rice),Qian You 1(three-line indica hybrid rice).seeds with 11%,13%and 14.5%seec moisture content(MC),were packed by both paper and palistic bags,and then stored at room temperature,15℃ and 5℃.The changes of seed vigor,viability and other parameters of seed stored at different packing materials and conditions were measured after 3,6,12 and 18 months storage.The contents of abscisic acid(ABA),gibberellin A3(GA3)and their related genes after seed storage were measured.The main results of the present study were as follows:There were no significant differences in seed vigor and viability of the two hybrid rice seeds after 3 and 6 months storage under different seed moisture contents at room temperature.For seed to be used for next season sowing(storage from 3 to 6 months),13%moisture content was the suitable level for Qian You 1 and Y Liang you 689,which matched with seed quality standard.After 12 and 18 month storage at room temperature,seeds with 11%MC significantly higher than those of 13%MC in seed vigour and viability,then 13%MC seeds significantly higher than those of 14.5%MC.It suggested that the suitable seed moisture content of the seed stored at room temperature for 12 months was 11%for Y Liang you 689 and 13%for Qian You 1.The suitable MC of the seed stored at room temperature for 18 months was 11%for Qian You I,however,for Y Liang you 689,its germination percentage was lower than 80%that is the lowest standard of hybrid seed germination,it needed future study about its suitable MC.When storage at 15℃,there was no significant difference in seed vigor and viability of the two hybrid rice seeds after 3 and 6 months storage under three kinds of MC.After 12 and 18 month storage at 15℃,vigor and viability of seeds with 11%and 13%MC significantly higher than those of 14.5%MC.It suggested that the suitable seed moisture content of the seed stored at 15℃ for 12 month was 13%for Y liangyou 689 and Qian You1,the suitable mositure content of the seed stored at 15℃ for 18 month was 11%for Y liangyou 689 and 13%for Qian You 1.When storage at 5℃,there was no significant difference in seed vigor and viability among three kinds of MC in both cultivars,their safe storage seed moisture content was 13%.After storage for 18 months,the storage ability of the three hybrid rice seeds was different,when they are both indiaca hybrid rice the three line hybrid rice Qian you1 was better than two line Y liangyou 689.Seeds stores in paper bags recorded the higher seed vigor and viability under room temperature when seed moisture cintent keep at 13%and 14.5%levels than those in plastic bags.On the other hand,seed stored in plastic bags recorded higher seed vigor and viability when seed moisture keep at 11%level.Whereas,seed stored at 15 ℃ for 18 months recorded higher seed vigor and viability when seed storage with 11%and 13%MC level in plastic bags than those in paper bags,however,seeds with 14.5%MC in paper bags storage recorded the higher seed vigor and viability than those in plastic bags.When seeds storage at 5℃ for 18 months,there was no significant difference in seed vigor and viability between two kinds of packing methods in both cultivars.The activity changes of a-amylase,peroxidase(POD),catalase(CAT)and ascorbate peroxidase(APX)under different sorage treatment was investigated,changes of those parameters were consistent with vigour changes.These paeameters could reflect seed quality.The contents of ABA increased with the increase of seed seec moisture content when storaged at room temperature,however there was no significant different among three kinds of MC at 15℃ and 5℃.There was no significant difference in ABA between two packing methods at three storage temperatures.There was a trend that the lower vigour of the seed,the higher the ABA content.The seed MC affected the content of GA3,seeds with higher MC had the lower seed vigor and the lower GA3 content.Howere,the storage temperature and packings had no significant effect on the GA3 content after storage.The expression of OsABAox2 related ABA synthetise and OsNCED2 related ABA resolving was lower in higher vigor seeds after storage in two packing methods and three kinds of seec moisture content at 15℃ and 5℃ in both cultivars,so the ABA content was in lower level.Also the expression of related GA3 OsGA20ox1 synthetise was higher,the expression of OsGA2ox5 related GA3 resolving was lower,so the content of GA3 was in higher level,therefore there was more GA3 accumulation that promoted the seed germination.