THE CORRELATION OF VEGETATIVE AND GENERATIVE CHARACTERS OF DUKU ( LANSIUM DOMESTICUM CORR . ) ACCESSION IN BANYUASIN REGENCY , SOUTH SUMATRA

The development of duku plantation in other regencies is required to enrich duku germplasms in South Sumatra. Banyuasin Regency in South Sumatra was chosen as research location for this study since many duku plantations are located in this area.This research was aimed to observe the correlation of vegetative and generative characters of duku accession in Banyuasin Regency.The research was conducted for 10 months in 2017 located in three areas of Banyuasin Regency, which are Banyuasin 1 (BA1), Banyuasin 2 (BA2) and Banyuasin 3 (BA3) with 5 plants per area resulting in total 15 plants. Purposive sampling method was used to determine the samples. Variability analysis and the calculation for correlation among vegetative and generative characters then were performed. Results showed that the characters of duku accessions indicated positive and negative correlation. Fruit sweetness level, however, did not show any correlation with either vegetative or generative characters.

Indonesia with its tropical weather provides a favorable environment for growth and development of various fruit commodities, including for local Indonesian fruits.However, unfortunately, the local fruit is mostly not properly cultivated and well utilized.Fruit production in Indonesia increases year by year following the increasing demand of fruit consumption.Indonesian fruit consumption per capita was 23.56 kg in 2006 increasing to 32.59 kg in 2010.Nevertheless, this number is still far below the reccommended standard of Food Agricultural Organization (FAO) which is 65 kg per capita per year.
Duku (Lansium domesticum Corr.) is a fruit tree originated from Indonesia and has been widely distributed across Indonesia with the production center located in Sumatra island (South Sumatra, West Sumatra, and Jambi), Java island (Central Java and Jakarta), and Kalimantan island (West Kalimantan) (Directorate General of Horticulture, 2015).Duku fruit is considered to have a high commercial value and competitive to other fruit commodities.It is favorited due to its sweet taste and odorless smell and it also has fairly nutrient content.In every 100 g, it contains 42 cal, 0.7 g protein, 13 g carbohydrate, 13.0 mg calcium, 20.0 mg phosphorus, 3.2 g fiber, 0.06 mg vitamin B1, 3.8 mg vitamin C and 0.9 mg Zinc (Mayanti, 2009).Yet, duku production in Indonesia is recently in the decreasing trend.The production in 2012 -2014 in respectively was 258,453; 233,118; 208,424 ton per ha per year (Central Bureau of Statistic, 2015).
South Sumatra Province is one of germplasm center of various fruit commodities, especially duku plant.South Sumatra duku production was 10,457 ton contributing in 5.02% of national duku production (Central Bureau of Statistic, 2015).Duku originated from South Sumatra is very popular and even has its own trade mark in the national market with the nickname of "Duku Palembang", while in the local South Sumatra market is known as "DukuKomering".Therefore, South Sumatra government has determined duku as mascot flora in the province (Deroes and Wijaya, 2010).
Duku plants in South Sumatra are mostly grown along the river basins of Komering, Ogan, Lematang, and MusiRiver distributed in seven regencies which are Ogan Komering Ulu (OKU), OganKomeringIlir (OKI), Banyuasin, Musi Banyuasin, Muaraenim, Musi Rawas and Lahat.Duku plant from each regency has different phenology in both vegetative and generative (fruit quality) growth.Duku of OKU has been determined as variety based on the Decree of Agricultural Ministry No. 31/Kpts/tp.240/95stating that Rasuan cultivar and Palembang cultivar were appointed as two national duku varietiesoriginated from South Sumatra (Seed Inspection and Certification Center of South Sumatra, 1999).However, both cultivars are most known in national market as Duku Palembang.The characteristics of Duku Palembang are the sweet taste and thin fruit peel (Uji, 2007).Duku cultivation is potential to be developed commercially due to the high demand of duku fruit for either freshly consumption or fruit drink ingredients.Furthermore, duku price is relatively higher compared to other similar commodities.This condition should be used as a great opportunity for increasing the income and welfare of duku farmers and duku related stakeholders (Pane, 2011).
The development of duku plantation in other regencies is required to enrich duku germplasms in South Sumatra.BanyuasinRegency in South Sumatra was chosen as research location for this study since there are many duku plantations in this area.Kusandaryani and Luthfy (2006) stated that the efforts to anticipate plant gene erosion by conserving the genetic materials were needed to be performed, either through exploration, characterization, rejuvenation, or documentation.
The inventory activities in several locations in Banyuasin was conducted to collect the data of duku accession in these areas.The activities included exploration and identification (Yuniarti, 2011).Plant morphological identification was carried out by observing the leaves, stems, flowers, fruits, roots and other morphological characteristics.The characteristic that could be used as anatomy marker is leaf stomata (Damayanti, 2007).Physiological characteristics such as nitrogen content, leaf chlorophyll and leaf sucrose were essential to indicate photosynthesis process in plant.Hanumet al. (2013) stated that the characters of morphology, anatomy and physiology were affected by both environment and genetic.Environmental difference will result in varied characters in plant creating many accessions in some locations.Morphological variation in duku plants are shown in the trees, leaves and fruits.
Thus, the study was conducted to observe the correlation among vegetative and generative characters of duku accession in Banyuasin Regency.The data obtained could further utilized as a base information for Banyuasin duku position as duku germplasm resource in South Sumatra.
Methods used were survey and literature study.Sampling was performed by using purposive sampling method.Five plant samples were observed in each location resulted in total 15 plant samples.Research steps included survey, research sites determination, and purposive sampling.Vegetative characters were observed in stems and leaves, while fruits were observed for the generative characters.The observation in stem morphology consisted of the parameters of plant height, stem girth and branching type.The analysis of leaf morphology, leaf anatomy and leaf physiology was carried out in the laboratory of Plant Physiology, Department of Agronomy, Faculty of Agriculture, University of Sriwijaya.
Leaf chlorophyll was analyzed by soaking 2 cm x 2cm of fresh leaf samples into 10 ml of ethanol 80% for about 48 hours in dark room.The absorbance then was determined using spectrophotometer with 650 and 665 nm of wavelength (Hall and Rao, 1987).Antrone method was used to determine leaf sucrose. 2 g of fresh leaf was added with 15 ml of ethanol then crushed in the mortar.Another 10 ml of ethanol then was added to the crushed leaf samples.It was then filtered and heated in 70 0 C temperature for 30 minutes.After cooling down, 0.2 ml of sample solution was added with 6 ml antrone (0.25 antrone + 177.5 ml H 2 SO 4 + 72.5 ml of water).The solution was heated until it changed into blue-ish color.After cooling down, the absorbance was determined using spectrophotometer with 600 nm.Leaf nitrogen was determined by using Kjeldahl method.0.1 g of dry samples added with strong sulphate acid was heated in the acid room.Destillation process then was performed by using Borax acid and indicator.The solution then was titrated with 0.01 N of sulphate acid until the color changed into red (Lorenz, 1978).
Data resulted then were descriptively analyzedand calculated for the correlation among characters.Phenotypic variance analysis and deviation standard were used to determine the range (large or narrow) of the observed characters' variability.Deviation standard and phenotypic variance were also calculated.Characters variability was determined based on Daradjat (1987) method.Large variability was occurred when the variance was bigger than twice of deviation standard ( > 2.Sd ), and narrow variability when the variance is less than twice of deviation standard.All collected data were presented in form of tables and figures.

RESULTS AND DISCUSSION
Vegetative Characters.The characters of morphology, anatomy and physiology were observed as the vegetative characters.Morphological characters then were divided into quantitative and qualitative morphology.Quantitative morphology then was used as phenotypic variability analysis.The observation for quantitative morphology obtained the data of plant height, stem girth and leaf width.
The tallest tree was found in BA 23 location with 25.0 m and the lowest was in BA 12 with 6.0 m.The largest stem girth was BA 21 with 170 cm and the smallest was in BA 12 and BA 31 with 34 cm.The longest and widest leaf was found in the same location in BA 22 with 23.43 cm and 10.55 cm respectively.However, the shortest and narrowest leaf was from different location.The shortest leaf was in BA 13 with 18.71 cm and the narrowest leaf was in BA 33 with 7.78 cm.The difference in leaf morphology was due to the difference in temperature, humidity, and light intensity intercepted by the leaves (Pompelliet al., 2010; Sholikhahet al. 2015)(Figure 1-4).
The qualitative morphology based on Munsell Colour Book and Manual of Leaf Architecture (Ash et al.,199)showed the similarity for all the observed characters in all locations.The branching type was monopodial with an obvious main stem which was bigger and taller compared to the branches.The branches direction was also tend to go upward.Leaf shape was elliptic with 1.5-2 : 1 of comparison between leaf length and leaf width while leaf petiole was on the lamina.Leaf margin was entire with thin segment and no fiber layer.Leaf base shape was complex and leaf tip was acuminate, while leaf venation type was a pinnate with single leaf vein.Leaf greeness level was 3/4 7.5 GY (data not shown).
Both quantitative and qualitative data for leaf anatomy were obtained through microscopic observation.Quantitative data includednumber of abaxial and adaxial stomata, and stomata shape was as qualitative data.The number of abaxial stomata was relatively higher than adaxial stomatafor about 20.75 -29.50 in which the highest was found in BA 25 and the lowest was in BA 11 , BA 23 and BA 31 , while adaxial stomata was around 5.75 -9.25 where the highest was in BA 14 and the lowest was in BA 32 (Figure 5).Stomata number was counted in each microscopic viewing with 40 x 10 magnification.According to Yuliasmara and Ardiyanti (2013), leaf would tend to have more number of leaf stomata on the under surface of the leaf compared to the leaf surface.The higher number of stomata, the higher stomata density.Yulianti et al. (2010) stated that stomata density could be determined as the character identifying plant disease resistancy.
Result showed that stomata shape was anomocytic shapecharacterizedby the guard cell surrounded by five or more epidermic cells so that the shape would look like a pentagon.Based on stomata position, duku leaf was identified as an amphystomatic type (data not shown).It is a type of leaf that has stomata in both sides of the leaf (Rushayati and Maulana, 2005).Leaf chlorophyll was analized in the laboratory resulting in 10.54 -30.45 mgg -1 of chlorophyll content.The highest was resulted in location BA 13 and the lowest was in BA 14 (Figure 6).Leaf nitrogen was around 0.28 -1.68% and leaf sucrose was 0.03 -0.44%.The highest nitrogen was from BA 31 and the lowest was from BA 21 , while for sucrose the highest was BA 21 and the lowest was BA 13 (Figure 7).Ai Song and Banyo (2011) stated that leaf chlorophyll was influenced by environmental factors such as light intensity and H 2 O. Leaf nitrogen could be used as an indicator for photosynthesis activity since nitrogen is one the constituent elements of chlorophyll required for carbohydrate formation in photosynthesis (Hernita et al., 2012).Anggarwulan et al. (2008) added that leaf nitrogen was also influenced by H 2 O. Leaf sucrose resulted a varied data which might be caused due to either environmental (such as ground water content) or genetical factor by SUT gene expression or sucrose transporter (Novita et al., 2007).Generative Characters.The obtained data of generative characters consisted of fruit length (cm), fruit diameter (cm), fruit peel thickness (g), fruit weight (g), number of slices per fruit, number of seed per fruit and sweetness level ( o brix).Fruit length was around 2.70 -3.46 cm where the longest fruit was resulted from location BA 25 and the shortest was in BA 22 .Fruit diameter was around 2.18 -2.71 cm where the largest was in BA 12 and the smallest was in BA 33 .Fruit peel thickness was around 0.15 -0.23 cm where the thickest was in two locations BA 25 and BA 34 , while the thinnest was in BA 22 (Figure 8).Fruit was around 9.26 -16.10 g where the heaviest was in BA 12 and the lightest was resulted from two locations BA 21 and BA 31 (Figure 9).Number of slices per fruit was around 4.67 -5.00 where the highest number was resulted from 4 locations: BA 12 , BA 13 , BA 14 and BA 22 .While the lowest number was in BA 34 (Figure 10).Seed number per fruit was around 0.00 -0.83 where the highest was in BA 11 and the lowest was in BA 21 (Figure 11).Sweetness level was around 18.82 -22.28 o brix.The highest was in BA 25 and the lowest was in BA 34 (Figure 12).Analysis of Variability and Correlation among Characters.Phenotypic variability analysis was performed based on the characters of quantitative morphology, quantitative anatomy and physiology.Results showed that both wide (varied) and narrow (similar) variability were found in the accession of duku in Banyuasin Regency (Table 1).Note: variability determined using the method of Daradjat (1987).
Large variability was resulted when the variance was more than twice of deviation standard, while if the variance was less than twice of deviation standard, narrow variability was resulted.Large variability was resulted from the characters of tree height and stem girth, while other characters resulted a narrow variability.The difference of variability might be caused by envionmental factor (phenotypic variability) and genetic factor (genetic variability).According to Ruchjaningsih et al. (2002), a character with narrow variability indicated a relatively simiar population so that it was rather impossible to carry out a selection for character improvement.Furthermore, Alnopri (2004) added that large variability was considered as one of selection requirements for certain desired character.Based on the correlation analysis of vegetative and generative charaters, it was found that tree height had significant positive correlation with stem girth and significant negative correlation with fruit diameter and number of seed per fruit, and also had significant correlation with fruit weight.Stem girth showed a significant negative correlation with number of seed per fruit.While leaf length had significant positive correlation with leaf width and significant negative correlation with fruit length and fruit peel thickness.Leaf width showed significant negative correlation with fruit length and fruit peel thickness.Fruit length had significant positive correlation with number of seed per fruit and fruit peel thickness.Fruit diameter showed siignificant positive correlation with fruit weight, and fruit weight was positively correlated with number of seed per fruit significantly.

Figure 7 -
Figure 7 -Leaf and sucrose content of duku succession in Banyuasin Regency

Figure 8 -
Figure 8 -Fuit length, diameter and fruit peel thickness of duku accession in Banyuasin Regency

Figure 9 -
Figure 9 -Fruit weight of duku accession in Banyuasin Regency

Figure 10 -Figure 11 -Figure 12 -
Figure 10 -Number of slice per fruit of duku accession in Banyuasin Regency

Table 1 -
Variability analysis of duku accession in Banyuasin Regency