تاثير اندازه مريستم، گرما و اثر متقابل آنها بر روند توليد گياهچه و ريزغده عاري از ويروس در ارقام سيب زميني

Meristem Culture and Heat Treatments in Production of Virus-Free Plantlet and Potato Mini Tuber

Pothogenic viruses inflict a lot of damage to potato crop annually. A control of viral diseases after their spread is often impractical and impossible. The best way to inhibit and/or combat viral diseases is to produce virus free seeds. In the ongoing study potato seed tubers of several varieties including Agria,Picaso,Diamond and Marfona were picked up for a study of the way(s) to eliminate viral infestations. Tubersʹdormancy was broken through stratification .Following sprouting of the seeds and their planting in pots,samples were taken from a bout 25 cm plantlets in some pots for meristem culture. The rest, to be thermally treated, were kept in a day temperature of 36 ± 1°C and 32 ± 1°C during The night for a duration of one month. The plant stems were disinfected through undergoing laminar flow, their meristems (in sizes of 0.2 , 0.5,1,and 5 cmm) being cultured on paper bridges inside sterile glasses that contained liquid culture medium MS, NAA and BAP hormones of various concentrations along with supplements. Cultured samples were transferred to a growth chamber of 24°C temperature and photoperiodism of 16/8 with a light intensity of 3500-4000(Lux). Samples were taken from p;antlets (meristem growths) for a determination of viruses PVA, PVS, PVX and PVY degree of infestation. Results indicated a thorough control of viruses PVS and PVX in plantlets undergoing heat treatment. An infestation of 60-70 percent was evident for other viruses concerned. On the other hand,in plantlets that were the result of direct meristem culture, viruses PVA and PVY came undre control to an extent of 90%, while viruses PVS and PVX inflicted infestation of about 40% Results obtained from a mix of the two methods revealed a complete control of viruses PVS, and PVX and with only 10% of the plantlets being infested with viruses PVA, and PVY. This indicates the fact that the best way to contain viral infections would be to adopt a combination of heat treatment plus direct meristem culture.