| Summary: | Fusarium wilt is main disease in melon. This disease is devastating until
60%. In-vitro selection and gamma irradiation are well known as effective method
to improve plant resistance. This thesis consists of two part of research. Chapter
one is discussing about �Study of in-vitro resistance melon to fusarium wilt and
its relation with salicylic acid content� and chapter two is discussing about �Effect
of gamma ray on increasing resistant explants to fusarium wilt�. First part is
aimed to find out an appropriate concentration of fusaric acid for selection to
fusarium wilt stress in in-vitro condition, to obtain resistant candidate plants to
fusarium wilt, and to study relation between salicylic acid content with plant
resistance to fusarium wilt in melon. While in second part is aimed to find an
optimum dose of gamma ray that able to generate highest resistant plantlet.
Experiments were conducted from October 2011 until December 2012. Invitro
selection was done in Plant Tissue Culture Laboratory of PT. BISI
International Tbk,. Kediri. Analysis of salicylic acid content was executed in Plant
Physiology Laboratory of PT. BISI International Tbk,. Meanwhile gamma ray
treatment was conducted in National Atomic Agency (BATAN) Jakarta and
resistance evaluation of resistant candidate plants was conducted in Plant
Protection Laboratory of PT. BISI International Tbk,.
Five lines of melon were used as source materials in this experiment i.e.
M-8, M-13, M-21, M-27, and M-72. Concentrations of fusaric acid were consist
of 0 ppm (as control), 15 ppm, 30 ppm, and 60 ppm. Lethal concentration 50% of
fusaric acid (LC50) then was used as selection medium for explants that were
exposure by gamma ray. Gamma ray doses that were utilized in this research i.e. 0
Gray (Gy) as control, 15 Gy, 30 Gy, and 45 Gy. Surviving plantlets in selection
medium were measured their salicylic acid content and be compared to plants at
the field to investigate salicylic acid pattern in those materials. Those plantlets
were acclimatized and then were self- pollinated to obtain seeds material. Seeds
then were sown and the seedlings were inoculated fusarium to evaluate
relationship between resistance levels in in-vitro stage with at seedling phase.
The result showed that concentration of fusaric acid in 30 � 60 ppm is
effective as selection agent to simulate fusarium wilt stress in in-vitro selection.
Most resistant line in in-vitro selection is M-21. However, M-13 line is highest
regenerate explants and highest of resistant explants amount after irradiation
treatment. Therefore, M-13 was used as role model in resistance evaluation.
The line possessed high endogenous salicylic acid content revealed better
resistance level. Moreover, the raising of salicylic acid content of plantlets on
selection medium and in plants after inoculation implying plants response to
pathogen infection. Resistance evaluation at the field showed that resistance in invitro
level is related with resistance at the field level. Plants derived from in-vitro
selection and gamma ray irradiation treatment possess better resistance than their
initial line. In the other word, in-vitro selection and gamma ray irradiation is
effective to improve melon resistance to fusarium wilt.
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