Karakteristik Tanaman Batang Bawah Jeruk Dan Kontribusinya Terhadap Kompatibilitas, Fisio-Genetik Dan Mutu Buah Jeruk Keprok Rimau Gerga Lebong (Rgl)

Yulianti, Farida and Prof. Ir. Sumeru Ashari,, M.Agr.Sc., Ph.D and Prof. Ir. Lita Soetopo,, Ph.D and Afifuddin Latif Adiredjo,, SP., M.Sc., Ph.D (2021) Karakteristik Tanaman Batang Bawah Jeruk Dan Kontribusinya Terhadap Kompatibilitas, Fisio-Genetik Dan Mutu Buah Jeruk Keprok Rimau Gerga Lebong (Rgl). Doktor thesis, Universitas Brawijaya.

Abstract

Indonesia memiliki sumberdaya genetik jeruk keprok yang tinggi dengan produksi jeruk pada tahun 2019 sebesar 2.543.485 ton. Tingkat kebutuhan konsumsi jeruk nasional yang terus meningkat menyebabkan nilai impor jeruk juga meningkat. Pada tahun 2019, nilai impor jeruk Indonesia sebesar 137.585 ton, naik sebesar 88.5 persen dibandingkan tahun 2018. Oleh karena itu, perlu dilakukan upaya peningkatan produktivitas melalui intensifikasi dan ekstensifikasi. Upaya intensifikasi dapat dilakukan dengan menggunakan varietas jeruk unggul, salah satunya adalah jeruk keprok Rimau Gerga Lebong (RGL). Keunggulan jeruk RGL adalah warna kulit dan daging buah oranye, ukuran buah besar, kadar jus tinggi, buah yang padat, dan produksi tinggi. Upaya ekstensifikasi dapat dilakukan dengan menggembangkan tanaman jeruk di daerah suboptimal. Kendala tanaman pengembangan jeruk di daerah suboptimal adalah tanaman batang bawah yang digunakan saat ini (Japansche citroen (JC) dan Rough Lemon (RL) kurang tahan terhadap cekaman biotik dan abiotik. Penggunaan tanaman batang bawah selain JC dan RL dalam pengembangan kawasan jeruk di Indonesia perlu dilakukan. Citrumelo dan Kanci adalah tanaman jeruk batang bawah yang memiliki potensi untuk dikembangkan di Indonesia. Citrumelo memiliki sifat toleran terhadap kekeringan, ketahanan menengah terhadap kondisi salinitas tinggi, toleran terhadap CTV, toleran terhadap CEV, tahan Xylospora dan nematoda jeruk, toleran terhadap fitoptora, toleran terhadap kekurangan unsur Fe, Boron dan toleran terhadap Citrus Sudden Death. Tanaman Kanci memiliki potensi dapat membentuk tanaman menjadi kerdil dengan volume kanopi sempit sehingga dapat meningkatan densitas tanaman per satuan luas. Sayangnya data karakter dan kompatibilitas kedua tanaman tersebut terhadap jeruk keprok RGL belum tersedia. Selain itu, kontribusinya terhadap pertumbuhan tanaman dan mutu buah jeruk keprok RGL juga perlu dievaluasi. Tujuan penelitian adalah (1) mendapatkan karakteristik tanaman jeruk batang bawah JC, Citrumelo dan Kanci, (2) mendapatkan karakter pertumbuhan benih jeruk batang bawah JC, Citrumelo dan Kanci, (3) mendapatkan tanaman batang bawah yang kompatibel terhadap jeruk keprok RGL, dan (4) mendapatkan tanaman batang bawah terbaik untuk tanaman jeruk keprok RGL berdasarkan variabel fisio-genetik, produktifitas dan kualitas buah. Penelitian dilaksanakan di KP Tlekung dan Laboratorium Pemuliaan Tanaman, Balai Penelitian Tanaman Jeruk dan Buah Subtropika mulai Bulan Juli 2019 sampai September 2020. Penelitian dilaksanakan dalam empat kegiatan penelitian, yaitu (1) karakterisasi tanaman jeruk batang bawah Japansche citroen (JC), Citrumelo dan Kanci, (2) analisis pertumbuhan semai biji jeruk JC, Citrumelo dan Kanci, (3) pengujian kompatibilitas dan pertumbuhan tanaman jeruk keprok RGL yang diokulasi pada batang bawah JC, Citrumelo dan Kanci dan (4) pengujian kontribusi tanaman jeruk batang bawah (JC, Citrumelo dan Kanci) terhadap fisio- genetik dan kuantitas serta kualitas buah tanaman jeruk keprok RGL. ix Penelitian pertama merupakan penelitian deskriptif dengan pendekatan kualitatif dan kuantitatif. Pada penelitian pertama, kegiatan karakterisasi morfologi, ploidi dan genetik tanaman jeruk batang bawah JC, Citrumelo dan Kanci dilakukan terhadap duplikat pohon induk tunggal JC, Citrumelo dan Kanci. Karakterisasi dilakukan terhadap karakter pohon, daun, bunga buah dan biji sesuai dengan panduan karakterisasi jeruk yang dikeluarkan oleh IPGRI. Karakterisasi genetik dilakukan dengan menggunakan primer spesifik terkait ketahanan terhadap cekaman biotik dan abiotik. Hasil penelitian menunjukkan bahwa tanaman jeruk JC, Citrumelo dan Kanci memiliki karakter morfologi dan genetik yang bervariasi. Karakter morfologi penting untuk tanaman batang bawah adalah vigor tanaman, luas kanopi tanaman, produksi buah, jumlah biji dan embrioni biji. Tanaman JC memiliki vigor besar dengan kanopi lebar, produksi buah tinggi dengan jumlah biji per buah banyak dan biji bersifat poliembrioni. Tanaman Citrumelo memiliki vigor besar dengan kanopi sempit, mengalami gugur daun pada musim kemarau, produksi buah tinggi dengan jumlah biji per buah banyak dan biji bersifat poliembrioni. Tanaman Kanci memiliki vigor kecil dengan kanopi sempit, berbuah sepanjang tahun dengan durasi pematangan buah pendek dan biji bersifat poliembrioni. Secara genetik, ketiga jenis batang bawah memiliki potensi toleran terhadap cekaman kekeringan namun sensitif terhadap cekaman salinitas dan CTV. Penelitian kedua dilaksanakan dengan Rancangan Acak Kelompok (RAK) dengan varietas tanaman jeruk batang bawah JC, Citrumelo dan Kanci sebagai faktor. Peneltian dilakukan dengan empat ulangan, masing-masing ulangan terdiri dari 25 benih. Pada penelitian kedua, analisis pertumbuhan tanaman jeruk batang bawah dilakukan dengan mengamati persentase benih tumbuh, tinggi tanaman, keragaan akar dan anatomi irisan melintang akar dan batang semai biji jeruk JC, Citrumelo dan Kanci. Pengamatan tinggi tanaman dilakukan hingga tanaman berumur empat bulan setelah semai. Hasil penelitian menunjukkan bahwa benih jeruk JC dan Citrumelo memiliki kecepatan pertumbuhan yang lebih baik dibandingkan Kanci. JC dan Citrumelo memiliki persentase benih tumbuh, karakter perakaran, dan anatomi ksilem (persentase dan luas pembuluh ksilem) yang lebih tinggi dibandingkan Kanci. Karakter ksilem berkorelasi positif terhadap pertumbuhan tanaman. Tinggi tanaman jeruk batang bawah dapat diprediksi dengan model matematis: “Tinggi tanaman = 23.697 + (0.094xpersentase ksilem akar) + (0.435xpersentase ksilem batang) + (0.001xluas pembuluh ksilem akar) + (0.001xluas pembuluh ksilem batang)”. Penelitian ketiga dilakukan dengan metode penelitian deskriptif melalui pendekatan kualitatif. Pada penelitian ketiga dilakukan okulasi mata tunas jeruk keprok RGL pada tanaman batang bawah JC, Citrumelo dan Kanci dan pengamatan kompatibilitas okulasi. Variabel pengamatan pada penelitian ketiga adalah persentase keberhasilan okulasi, anatomi sambungan di titik okulasi, morfologi di daerah sambungan, pertumbuhan tanaman (tinggi tanaman dan diameter batang), volume kanopi dan jumlah daun. Hasil penelitian menunjukkan bahwa kompatibilitas antara tanaman jeruk batang atas terhadap batang bawah ditunjukkan oleh perlekatan mata tunas pada awal okulasi, pembentukan sambungan yang sempurna dan dukungan jangka panjang terhadap pertumbuhan tanaman jeruk batang atas. Tanaman jeruk keprok RGL bersifat kompatibel terhadap batang bawah JC dan Citrumelo namun bersifat late incompatibility dengan batang bawah Kanci. Kombinasi RGL-JC dan RGL-Citrumelo menyebabkan tanaman lebih vigor dibandingkan kombinasi RGL-Kanci Penelitian keempat dilaksanakan dengan Rancangan Acak Kelompok dengan varietas tanaman jeruk batang bawah JC, Citrumelo dan Kanci sebagai x faktor. Penelitian dilakukan dengan lima ulangan. Pada penelitian keempat, penelitian dilakukan terhadap tanaman jeruk keprok RGL umur tiga tahun dengan batang bawah JC, Citrumelo dan Kanci. Variabel pengamatan terdiri dari analisis stomata, indeks klorofil, parameter pertukaran gas, akumulasi unsur hara di daun, analisis ekspresi gen terkait cekaman kekeringan dan induksi bunga, produktivitas tanaman dan kualitas buah. Hasil penelitian menunjukkan bahwa respon fisio- genetik tanaman terhadap lingkungan, produktivitas dan kualitas buah jeruk keprok RGL dipengaruhi oleh batang bawah yang digunakan. Tanaman batang bawah Citrumelo memberikan kontribusi terbaik terhadap tanaman jeruk keprok RGL dibandingkan JC dan Kanci. Tanaman batang bawah Citrumelo meningkatkan toleransi terhadap cekaman kekeringan, menginduksi potensi hasil per tanaman yang tinggi, panen pada periode late season (di luar musim), meningkatkan kadar jus buah, meningkatkan indeks kematangan buah, vitamin C dan total karoten buah. Tanaman batang bawah JC menginduksi hasil panen per tanaman dan kadar jus buah yang tinggi. Tanaman batang bawah Kanci menyebabkan kenaikan Brix dan total karoten buah. Produktivitas tanaman jeruk keprok RGL dapat diprediksi dengan model matematis: “Produktivitas tanaman = 951.629 + (0.123 x jumlah bunga) + (15.811 x volume kanopi) – (12.522 x ekspresi gen CHLASE) – (280.735 x ekspresi gen ETR1) – (118.317 x ekspresi gen ACS2) + (1595.780 x ekspresi gen CsSL1) + (465.917 x ekspresi gen CsAP1) + (1235.709 x ekspresi gen CsLFY)”. Kebaruan dari penelitian adalah: 1. Tanaman JC, Citrumelo dan Kanci memiliki potensi toleran terhadap cekaman kekeringan dengan memproduksi osmotin dan aquaporin dan sensitif terhadap cekaman salinitas dan CTV. 2. Karakter persentase dan luas pembuluh ksilem pada irisan melintang akar dan batang dapat digunakan untuk menduga pertumbuhan tanaman jeruk. 3. Tanaman jeruk keprok RGL bersifat kompatibel terhadap batang bawah JC dan Citrumelo namun bersifat late incompatibility dengan batang bawah Kanci. 4. Kombinasi jeruk keprok RGL dengan batang bawah Citrumelo cocok untuk dikembangkan di dataran tinggi kering untuk memproduksi buah pada periode late season dengan kuantitas dan kualitas buah yang tinggi. 5. Model matematis untuk memprediksi tinggi tanaman jeruk batang bawah dan produktivitas jeruk keprok RGL

English Abstract

Indonesia has high mandarin citrus genetic resources with citrus production in 2019 was 2.543.485 tons. The increasing of national citrus consumption caused increasing of the citrus import value. In 2019, Indonesian citrus import was 137.585 tons, 88.5 percent higher than in 2018. Therefore, it was necessary to increase the citrus productivity through intensification and extensification. The Intensification can be conducted by using superior citrus varieties, one of which was the Rimau Gerga Lebong (RGL) mandarin. The superiorities of RGL mandarin were the orange peel and flesh color, the large fruit size, the high juice content, the dense fruit, and the high productivity. The extensification can be conducted by growing citrus plants in suboptimal areas. The obstacle of citrus development in suboptimal areas was the susceptibility of citrus rootstock currently used (Japansche citroen (JC) and Rough Lemon (RL) to biotic and abiotic stresses. Using other rootstocks than JC and RL in the development of citrus areas in Indonesia should be conducted. Citrumelo and Kanci was potential citrus rootstock to be developed in Indonesia. Citrumelo was drought tolerant, medium resistance to high salinity, tolerant to CTV, tolerant to CEV, resistant to Xylospora and citrus nematodes, tolerant to phytophthora, tolerant to iron deficiency, boron and tolerant to Citrus Sudden Death. Kanci has the potential to form dwarf plants with a narrow canopy volume so that they can increase plant density per unit area. Unfortunately, the characters data and the compatibility of the both plants to RGL mandarin citrus were not yet available. In addition, its contribution to the growth of RGL mandarin citrus needs to be evaluated. The aims of the research were (1) to obtain the characteristics of JC, Citrumelo and Kanci rootstock, (2) to obtain growth characters of JC, Citrumelo and Kanci rootstock seedlings, (3) to obtain rootstock which compatible to RGL mandarin, and (4) to obtain the best rootstock for RGL mandarin based on physio- genetic, productivity and fruit quality variables. The research was conducted at Tlekung experimental garden and plant breeding laboratory of Indonesian Citrus and Subtropical Fruits Research Institute (ICISFRI) from July 2019 to September 2020. The research was carried out four studies, that were. (1) characterization of JC, Citrumelo and Kanci rootstocks, (2) growth analysis of JC, Citrumelo and Kanci seedlings, (3) examination of compatibility and growth of RGL mandarin grafted to JC, Citrumelo and Kanci rootstock, and (4) examination of contribution of citrus rootstock (JC, Citrumelo and Kanci) to physio-genetic, productivity and fruit quality of RGL mandarin. The first study was a descriptive study with qualitative and quantitative approaches. In the first study, the morphological, ploidy and genetic characterization of citrus rootstock (JC, Citrumelo and Kanci) were carried out on duplicates of a citrus mother plant. Characterization was carried out on the characters of trees, leaves, fruit flowers and seeds in accordance with the citrus characterization guidelines issued by IPGRI. Genetic characterization was carried out using specific primers related to resistance to biotic and abiotic stresses. The results showed that JC, Citrumelo and Kanci plants have varied morphological and xii genetic characters. The important morphological characters of rootstock plants were plant vigor, plant canopy volume, fruit production, number of seeds and seed embryony. Citrumelo plants had a large vigor with a narrow canopy, falling their leafs in the dry season, high fruit production with a large number of seeds per fruit and polyembryonic seeds. JC plants have large vigor with a wide canopy, high fruit production with a large number of seeds per fruit and polyembryonic seeds. Kanci plants have a small vigor with a narrow canopy, producing fruit all year round with a short fruit ripening duration and polyembryonic seeds. Genetically, the three types of rootstock had the potential to drought tolerant but sensitive to salinity and CTV. The second study was carried out with a randomized block design (RBD) with citrus rootstock varieties (JC, Citrumelo and Kanci) as factors. The research was carried out with four replications, each replication consisting of 25 seedlings. In the second study, the characterizations of the citrus rootstock growth were carried out by observing the percentage of seed growth, plant height, root performance and the anatomy of the transversal sections of the roots and stems of JC, Citrumelo and Kanci seedlings. Observation of plant height was carried out until the plants were four months after planting. The results showed that JC and Citrumelo seedlings had a better growth rate character than Kanci. JC and Citrumelo had higher percentage of seed growth, root character, and anatomy of the xylem (percentage and area of the xylem vessels) than Kanci. The xylems character had a positive correlation with plant growth. The height of citrus rootstock can be predicted using a mathematical model: "Plant height = 23,697 + (0.094*percentage of root xylem) + (0.435*percentage of stem xylem) + (0.001*area of root xylem vessel) + (0.001*area of stem xylem vessel)" The third study was a descriptive study with qualitative approaches. In the third study, RGL mandarin shoot buds were grafted on JC, Citrumelo and Kanci rootstocks and than the grafting compatibility were observed. The observation variables in the third study were the percentage of successful of grafting, the anatomy at the grafting point, morphology in the grafting area, plant growth (plant height and stem diameter), canopy volume and number of leaves. The results showed that he compatibility between the scion and rootstock was shown by the attachment of buds at the beginning of grafting, the formation of a perfect connection and long-term support for the growth of the scion. RGL mandarin was compatible with JC and Citrumelo rootstocks but late incompatibility with Kanci rootstocks. JC and Citrumelo caused the RGL mandarin to be more vigorous than that on Kanci. The fourth study was carried out with a randomized block design (RBD) with citrus rootstock varieties (JC, Citrumelo and Kanci) as factors. The research was carried out with five replications. In the fourth study, the research was carried out on three years old RGL mandarin grafted on JC, Citrumelo and Kanci rootstocks. The observation variables consisted of stomata analysis, chlorophyll index, gas exchange parameters, accumulation of nutrients in leaves, analysis of gene expression related to drought stress and flowering induction, plant productivity and fruit quality. The results showed that the physio-genetic response of plants to the environment, productivity and quality of RGL mandarin were influenced by the rootstocks used. Citrumelo gave the best contribution to RGL tangerines compared to JC and Kanci. Citrumelo rootstock increased tolerance to drought stress, induces high yield potential per plant, harvests in the late season period, increased level of fruit juice, increased fruit maturity index, vitamin C and total carotene of fruit. JC rootstock induced high yields per plant and high fruit juice content. Kanci rootstock plant caused an increase in Brix and total carotene fruit. Plant xiii productivity = 951,629 + (0.123*flower count) + (15,811*canopy volume) - (12,522*CHLASE gene expression) - (280,735*ETR1 gene expression) - (118,317*ACS2 gene expression) + (1595,780*CsSL1 gene expression) + (465,917*APsAP1 gene expression) ) + 1235,709*expression of the CsLFY gene) The novelties of the research are: 1. JC, Citrumelo and Kanci were able to amplify of osmotin and PIP primers so that they had the potential to be tolerant to drought stress by producing osmotin and aquaporin. The three types of rootstocks were unable to amplify specific primers related to salinity stress tolerance and CTV disease so they were more sensitive to salinity stress and CTV. 2. The character of percentages and area of ksilem vessels in the cross section of roots and stems can be used to predict the growth of citrus plant. 3. RGL tangerine plants were compatible with JC and Citrumelo rootstocks but late incompatibility with Kanci rootstocks. 4. The combination of RGL mandarin with Citrumelo rootstocks is suitable for planting in the dry highlands to produce fruit in the late season period with high fruit quantity and quality. 5. Mathematical model to predict the height of rootstock citrus and productivity of RGL mandarin

Item Type:	Thesis (Doktor)
Identification Number:	0621040002
Uncontrolled Keywords:	batang bawah, fisio-genetik, RGL, kompatibilitas, rootstock, physio-genetic, RGL, compatibility
Subjects:	600 Technology (Applied sciences) > 660 Chemical engineering and related technologies > 660.6 Biotechnology
Divisions:	S2/S3 > Doktor Ilmu Pertanian, Fakultas Pertanian
Depositing User:	Nur Cholis
Date Deposited:	22 Jul 2022 07:28
Last Modified:	22 Jul 2022 07:28
URI:	http://repository.ub.ac.id/id/eprint/192546

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