Mariana BD, Arisah H, Yenni, Selvawajayanti M. 2018. Seedless fruit pummelo induced by Gamma Ray irradiation: Fruit morphological characters and stability evaluation. Biodiversitas 19: 656-661. Pummelo is one of native citrus crops found in South East Asia including Indonesia. It is well known due to its big size and distinct taste compared to other citrus fruits. However, it contains many seeds, which may reduce the market demand and customer preferences. Therefore, the objective of this study was to generate seedless citrus by mutation techniques using gamma-ray radiation. The mutant induction of Pamelo Nambangan using gamma-ray radiation was conducted in 2003 using bud wood as plant materials. The bud wood was then irradiated with the dosage of 20, 40, and 60 Gy. The buds then grafted to Japansche Citroen rootstocks and maintained properly until the fruits could be observed. After three years of selection based on performance and fruit evaluation on MV2 generation, a mutant plant derived from 20 Gy irradiation treatments were obtained with improved character on the number of seeds. Pamelo Nambangan has more than 40 seeds/fruit and the mutant has less than 10 seeds/fruit on average. In the seedless mutant, it was observed that the mutant has embryo sac abortion leading to seedless fruit and low pollen viability (7.7%). The mutant has been released in 2016 as a new seedless pummelo variety under the name of ‘Pamindo Agrihorti’.

<p>Mutasi sinar gamma dapat terjadi secara acak pada level alelik yang menghasilkan keragaman genetik baru. Mutasi pada jeruk menginduksi keragaman karakter secara kuantitatif maupun kualitatif. Tujuan penelitian ini ialah mengetahui pengaruh mutasi terhadap peningkatan keragaman karakter buah pada mutan tanaman jeruk lokal SoE. Penelitian dilaksanakan di Kebun Percobaan dan Laboratorium Pemuliaan Tanaman Balai Penelitian Tanaman Jeruk dan Buah Subtropika Jawa Timur, tahun 2014. Pengamatan dilakukan secara deskriptif berdasarkan Internasional Plant Genetic Resources Institute (IPGRI), pada karakter bobot buah, tinggi buah, diameter buah, ketebalan kulit, jumlah biji, jumlah juring, volume jus, warna kulit buah, warna jus, dan rasa. Hasil penelitian menunjukkan bahwa pengaruh mutasi pada peningkatan keragaman karakter kualitatif relatif rendah; mutan hampir mirip dengan tanaman kontrol untuk karakter kualitatif. Perbedaan pada karakter kuantitatif, ditunjukkan dengan nilai koefisien keragaman 5,06-33,89%, nilai tertinggi pada karakter jumlah biji, sedangkan karakter jumlah juring memiliki nilai terendah. Terdapat tujuh aksesi yang yang menghasilkan buah dengan persentase buah seedless (jumlah biji ≤5) mencapai 90%. Mutasi induksi menyebabkan berkurangnya jumlah biji dan menurunnya ukuran ketebalan kulit buah dibanding dengan kontrol SoE. Berdasarkan analisis klaster, aksesi-aksesi mutan terseleksi mempunyai tingkat keragaman kecil dengan level kemiripan 76,40%.</p>

ABSTRAK. Protokol organogenesis untuk perbanyakan plantlet Citrumelo menggunakan metode transverse thin cell layer (tTCL) batang telah berhasil dikembangkan. Identifikasi stabilitas genetik tanaman hasil kultur jaringan mutlak diperlukan untuk menguji keberadaan off-type. Tujuan penelitian adalah untuk mengetahui potensi primer retrotransposon dan inter simple sequence repeat (ISSR) dalam mendeteksi stabilitas genetik tanaman Citrumelo dari periode kultur yang panjang. Penelitian dilaksanakan pada bulan Juni 2013 sampai dengan Oktober 2015 di Laboratorium Pemuliaan Tanaman, Balai Penelitian Tanaman Jeruk dan Buah Subtropika, Tlekung. Sebanyak empat penanda dengan urutan basa berulang, yaitu retrotransposon dan ISSR digunakan untuk menguji stabilitas genetik plantlet in vitro yang berumur 22 bulan dan untuk mengonfirmasi metode yang dapat diandalkan untuk perbanyakan jeruk Citrumelo yang true-to-type pada masa mendatang. Daun plantlet diseleksi dan diisolasi secara bulk. Amplifikasi dilakukan terhadap DNA dengan sistem bulk segregant analysis (BSA), dan kemudian dipisahkan menggunakan gel agarose. Tanaman in vitro yang sama secara morfologi dapat dibedakan oleh penanda INT-retrotransposon yang mendeteksi adanya kehilangan pita pada grup sampel dengan ukuran 550 bp. Keberadaan retrotransposon dalam genom berlimpah dan aktivasinya diinduksi oleh stres. Kondisi kultur jaringan berpotensi menginduksi aktivasi retrotransposon. Keragaman genetik diperoleh sebesar 2,6%, tetapi masih dapat diterima untuk plantlet yang dihasilkan dari kultur jangka panjang. Plantlet yang digunakan dalam penelitian ini adalah plantlet yang dikulturkan sejak awal tahun 2014 dan telah digunakan untuk mempelajari faktor media dan lingkungan kultur yang efisien pada Citrumelo selama periode 2014-2015. Aktivitas pengkajian variabilitas genetik plantlet yang dihasilkan melalui tTCL batang masih terus dilakukan. Kombinasi protokol dan deteksi berbasis penanda PCR menjadi sarana yang efektif untuk perbanyakan massa benih berkualitas hasil kultur jaringan untuk mendukung progam pemuliaan maupun perbenihan.Kata kunci: Citrumelo; tTCL; Variabilitas genetik; Retrotransposon; ISSR ABSTRACT. Assessment of genetic stability of long-term cultivation of plantlet derived tTCL Citrumelo using repetitive sequence primers. Regeneration of plantlet from organogenesis of stem transverse thin cell layer (tTCL) was achieved for Citrumelo, a valuable rootstock. Identification of the genetic stability of plant tissue culture is absolutely necessary. The aim of this study was to assess the potential retrotransposons and inter simple sequence repeat (ISSR) primers in detecting the genetic stability of the Citrumelo plantlet derived from tTCL technique. The research was conducted from Juni 2013 until October 2015 in Breeding Laboratory of Indonesian Citrus and Subtropical Fruits Research Institute. A four repetitive based sequences retrotransposon and ISSR marker assays were used to evaluate genetic stability of a group of 22 months old in vitro plantlets and to confir...

As a commodity that is cultivated vegetatively, strawberries have a relatively low genetic diversity. One effort to increase the diversity of strawberries and genetic quality improvement can be made by using gamma-ray radiation. In vitro explant of strawberry cv Early Bright were radiated with Gamma-ray P3TIR BATAN facility. Starting with a radiosensitivity test to find out Lethal Dose (LD) 50 with dosage level; 5, 10, 20, 30, 40, 60, 80, 100, 125, 150, 175, and 200 Gy. LD50 observations were carried out to get the optimal dose. The treatment of several doses of gamma-ray radiation showed varied results, with the percentage of explants living decrease by increasing the dose of irradiation. Irradiation dose until 10 Gy did not affect the survival rate of explant—the treatment dose of 80 Gy and above causes 100% mortality on the final observation. The dose of 60 Gy had a significant effect on shoot growth, as indicated by curly leaves' growth. The next optimal dose recommended for radiation is set at 20 and 30 Gy to anticipate genetic changes that are not morphologically expressed and to avoid the negative effects of morphological changes.

Strawberry plantlets of the ‘Earlibrite’ variety were irradiated with gamma rays to induce genetic variability for resistance to abiotic stress. This study aimed to identify the DNA polymorphism of ‘Earlibrite’ strawberry mutants using ISSR markers. For this purpose, a population of M1V0 strawberry plants was gamma-irradiated at 20 Gy. In addition, the irradiated plantlets were subcultured onto MS medium enriched with 0.13 M of 1-NAA and 2 M of 6-BAP. The genetic variation of the mutant was molecularly analyzed using the ISSR marker. Analysis was performed on M1V0 mutant plantlets. The results showed that 93.36% of 192 scoreable bands produced by the ISSR markers were polymorphic. An average of PIC values was 0.48 per primer with a range of 0.40 (ISSR_56) to 0.50 (ISSR_22, ISSR_55, ISSR_58, ISSR_60, ISSR_61, ISSR_62 and ISSR_L10). The primer MI ranged from 2.38 (ISSR_62) to 4.85 (ISSR_21). The genetic variation of mutant individuals ranged from 2.74% to 87.04% according to the Jaccard similarity index. Cluster analysis using ISSR markers grouped the ‘Earlibrite’ strawberry mutant genotypes into five distinct groups. It is concluded that 20 Gy gamma-ray induced mutation produces strawberry mutants and that ISSR was a valuable marker for mutant identification.