JAMBI LOCAL RICE VARIETY ( ORYZA SATIVA L . ) ADAPTATION SCREENING AGAINST DROUGHT STRESS DURING SEEDING

Screening Jambi local rice (Oryza sativa L.) adaptive to drought stress at seeding stage, aimed to obtain Jambi local rice variety which are adaptive to extreme drought conditions to be able to cope with uncertain rainfall rate as a result of climate change, a source of enrichment for the germplasm assembly and improving new varieties that can cope with global climate change in increasing rice produce. The research was conducted in 2013 at the Balai Besar Penelitian Padi, Kebun Percobaan Padi Muara Bogor (Rice Research Institute, Rice Experimental Farm Muara Bogor). Materials examined were Jambi local rice varieties based on exploration results in 2004, 2009 and 2013 conducted in Jambi province. Drought screening was performed on seedling at 14 and 21 days after sowing (DAS) with soil moisture level under 20% to 105 Jambi local rice varieties and 2 control varieties. The control varieties are Salumpikit (drought tolerant) and IR20 (drought sensitive) obtained from Balai Besar Penelitian Padi Kebun Percobaan Bogor. This research is selection process conducted on Jambi local rice varieties against drought stress performed during seeding phase. Observations were conducted on survival rate percentage (survival). The results exhibits 26 out of 105 local rice varieties were evaluated as drought resistant at soil moisture level ± 17%, 14 varieties are drought resistant 14 and 21 DAS, 10 varieties resistant to drought at 14 DAS and 2 drought resistant varieties at 21 DAS.

Uncertainty in rainfall distribution both at present and in the years to come would worsen as a result of global climate change.This would mean dry conditions occurring in the middle of rainy season capable of damaging plant growth, followed by flood at the end of rainy season which would affect rice yields (Kawasaki, 2010).Uncertainties associated particularly concerning rainfall patterns due to climate change.It is expected to be difficult in anticipating drought effect (Anonymous, 2011) .To overcome irregularities in rainfall patterns, rice varieties capable of adapting to global climate change and resistant to drought is required.It would encourage a positive impact on rice yields (Kawasaki, 2010).
Jambi Province possesses rice planting area 75.100 ha (BPS, 1996) with a number of local rice varieties.Local rice has been grown for generations and has adapted well to its environment.Local rice cultivars are valuable asset should they are managed appropriately (Siwi, and Kartowinoto, 1989).Diversity of local rice cultivars in Jambi is quite high, but there is no known variety possessing drought resistant characteristic.Information regarding the diversity of Jambi local rice drought resistance in growth phases, genetic and germplasm collections is not yet available.Therefore it is necessary to identify and evaluate rice variety and its germplasm to obtain variety possessing adaptive and drought resistant traits.
Managing rice plant genetic resources included efforts to preserve, secure, and utilizing genetic diversity as optimal as possible to render them useful.It is done both for present and future generation.Cultivated plants species possess valuable genetic resources for crop improvement program (Oldfield, 1989).
Operational measures in managing genetic resources are: 1) exploration, inventory, and identification of genetic resources, 2) collecting in ex situ and in situ manner, 3) passportization and documentation, 4) evaluation, characterization, and cataloging, 5) usage, selection, hybridization, and varieties assembly, 6) conservation and rejuvenating, and 7) material exchange, protection, and commercialization.
Rice plants cultivation in Jambi province is mostly conducted in a specific cultivation environment (agro-ecology specific) known as tidal rice cultivation, swamp rice cultivation, gogo rice cultivation and rain-fed rice cultivation.Most of these are marginal lands.Varieties grown in general are local varieties grown and adapted to suit environmental conditions, and has been grown for generations.
Exploration is activity of seeking, collecting and researching varieties in certain areas.Aryunis et al. (2004 and2009), Aryunis (2013) has explored local rice in rice tidal agroecosystem, rice rain-fed field, swamp / lowland rice field, payo rice, gogo rice and irrigated rice field.The exploration results found 105 local rice varieties from Jambi.Local rice has high adaptability to each agro-ecosystem, but there is no known drought resistance trait in them.Therefore this research aims to obtain local rice varieties in Jambi which is resistant to drought in seedbed phase.

MATERIAL AND METHODS
Research Material.Materials used in this study is local rice varieties from Jambi, based on exploratory research result of Aryunis et al., (2004 and2009) and Aryunis (2013) in agroecosystem wetlands and dry land in Jambi.There are 105 varieties and used two introduced varieties as control variety which are Salumpikit (drought tolerant) and IR20 (drought sensitive), varieties obtained from Kebun Percobaan Muara Balai Besar Penelitian Padi (Muara Rice Research Institute Experimental Farm) in Bogor, Urea, KCl, SP36, and rice field study site.
Tools used in this study is greenhouse utilized in drought screening test.Plastic tubs for seedling media 40 cm x 25 cm x 14 cm.Oven, Lux Hitester Hioki 3423 brand made in Japan, petridis cup, aluminum saucer and oil absorbent paper.
Research Time and Place.The experiment was conducted at Greenhouse of Kebun Percobaan Muara Balai Besar Penelitian Padi Bogor.This study was conducted from January to June 2013.
Research Method.Jambi local rice taken from exploration results are evaluated (screening) for determining survival rate during and after drought stress test.Screening was done at the seedling stage, at 14 and 21 DAS (days after sowing).Seeds sown in plastic tubs filled with field soil and created conditions according to standard operating procedures of rice cultivation on wet seedbed.Germinated seed in petridisc cup were sowed in seedling tub as much as 20 seeds (sprouts) for each variety in a test.Each tub possess 10 lines, two lines for drought tolerant and drought sensitive varieties.Treatment implemenation on drought seedbed media was carried out in accordance to seedling age by removing water on each plastic tub until water on media's surface runs out.The tubs are left to dry until a third of drought sensitive variety (IR20) leaves withered.After drought period was finished, seedbed soil samples were taken and their water content was analyzed .Recovery phase was conducted afterwards by providing water according to wet seedbed water requirements.Data were collected for grown seeds (vigor) and freshness criteria.
Data Analysis.To determine the treatment effect towards drought survival rate and seed height, researcher used descriptive analysis presented in tabular form.
Variable Observation.Observations on the percentage of survival (survival) is done 21 days after recovery (DAR) to seed which grew perfectly and retain freshness.Survival percentage is calculated as: local variety resistant seed percentage (T) divided by the number of seeds sown.The result of the survival rate calculation is exhibitted as follows: Number of surviving seed from tested local variety x 100% Number of sown seed Drought tolerance scoring is based on a standard evaluation system IRRI (1988) (Table 1).

Figure 1 -
Figure 1 -Screening phase of Jambi local rice variety adaptation to drought stress up to 14-17% water soil content (under permanent wilting point) applied to seeding bed at Rumah Kaca Balai Besar Padi or Balai Besar Padi Greenhouse Muara Bogor Experimental Garden at 2013: A. Drought stress process starts in seeding media at 100% water content.B. Ending drought stress process after water content reaches 14-17% and initiated recovery process.C. Seeds started to recover.D. Seedling leaves started to grow.E. Diffierentiates seeds with drought stress applied and non-applied.F. Seed leaves started to grow normally.G. Seeds grow normally, calculated grown seed's survival rate % at 21 days after seeding.H. Variety possessing highest survival rate percentage (90%).

Table 2 -
Screening result of Jambi local rice variety survival rate after drought stress applied at 14 and 21 DAS