Judul: Organogenesis and in vitro conservation of pummelo (Citrus maxima (Burm.) Merr.).
Abstrak: Indonesia has high diversity of pummelo (Citrus maxima (Burm.) Merr.) which economically potential. The pummelo diversity must be conserved to overcome its extinction due to biotic and abiotic stresses. In vitro conservation using slow growth technique can be considered as an alternative of ex-situ conservation. The objective of this research was to study pummelo organogenesis and to find out an effective medium to conserve pummelo using slow growth technique. Three experiments were conducted in this research to conserve pummelo. Organogenesis was induced on pummelo leaf, root and epicotyl to find out the best explant and medium to produce pummelo shoot effectively. Two conservation experiments using slow growth were conducted to find out the best medium to conserve pummelo. The first conservation experiment was done using reduction of MS medium and sucrose concentration, while the second conservation method was done using osmotic regulator and retardant. The results showed effective direct organogenesis of pummelo could be induced by culturing epicotyl explant vertically in MS medium without plant growth regulator under 24 hour light. In the first conservation experiment, the best medium to conserve pummelo using reduction of MS medium and sucrose concentration was MS medium without sucrose that inhibited leaf formation 37%, shoot elongation 75%, root elongation 49,4%, and the estimation to conserve pummelo was 30,7 months. While in the second conservation experiment, the best medium to conserve pummelo using osmoticum and retardant is MS + sorbitol 2% + paclobutrazol 7,5 ppm, that inhibited shoot length 65,1%, leaf formation 84,6%, root number 20%, root length 81%, and the estimation to conserve pummelo was 22,2 months. However, based on percentage of growth inhibition to the planlet and the appearance of the conserved planlet, the more suitable medium to conserve pummelo was MS + sorbitol 2% + paclobutrazol 7,5 ppm. After conservation periode, pummelo could grow normally in recovery medium (MS0) and aclimatization medium (soil : husk : compos = 2 : 1 :1).
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Judul: Characterization and evaluation of seeded and seedless Indonesian pummelo {citrus maxima (burm.) Merr.} accessions
Abstrak: Indonesia has many accessions of pummelo germplasms, but only a small number of the accessions are planted commercially. Genetic variation in the seed number per fruit in pummelo is high, ranging from seedless to very seedy. Thus pummelo is categorized as seeded, potentially seedless and seedless. The objectives of this research were: 1) to identify morphological, biochemical (isozyme) and molecular (ISSR) characters, and ploidy level of seeded and seedless pummelo accessions originated from Sumedang, Pati, Kudus and Magetan, 2) to identify fruit formation of seeded and seedless pummelo, 3) to evaluate fruit quality of seeded and seedless pummelo fruit quality during storage. The characterization research showed that morphological characters contributed in grouping pummelo accessions were epicarp thickness, leaf lamina margin, vesicle length, epicarp color, petiole wing width and fruit shape, while based on isozyme characters were MDH (Rf 0.11 and 0.14) and ACP (Rf 0.24 and 0.33). ACP band at Rf 0.24 could be used as marker to differentiate seeded and seedless pummelo accessions. Molecular characters supported in classification of pummelo accessions were PKBT8 500 bp, PKBT8 375 bp, PKBT7 750 bp, PKBT3 750 bp, PKBT8 625 bp and PKBT12 500 bp. Separation between seeded and seedless cultivars based on morphological characters occured at similarity coefficient of 0.63, while on isoenzyme characters occured at similarity coefficient of 0.49. Both seeded and seedless pummelo accessions were diploid (2n = 2x = 18). Observation on fruit formation between selected seeded and seedless pummelo demonstrated that those pummelo accessions were able to produce parthenocarpic fruits, but bored seeded fruits when self pollination was induced, thus indicated self-compatibility. Natural self-pollination on ‘Bali Merah 1’, ‘Bali Merah 2, ‘Nambangan’ and ‘Bageng’ yielded seedless fruits, but most of ‘Jawa 3’ was seeded. Artificial self-pollination on those accessions produced seeded fruits, thus showed ovule fertility. ‘Bali Merah 2’ was shown to have high parthenocarpic degree as indicated by less seed number (<10 seed per fruit) in all pollination treatments. Therefore seedlessness in those pummelo accessions was caused by parthenocarpy, was not by pollen and ovule sterility, selfincompatibility, or poliploidy. Evaluation of pummelo fruit quality showed seedless pummelos have higher vitamin C, naringin content and acidity than seeded accessions. Vitamin C and titratable acidity (TA) content decreased, but total soluble solids (TSS) and TSS/AT ratio increased during storage period. During storage, percentage of edible portion increased, mainly due to the decrease of peel weight. Percentage of fruit axis of seedless accessions was smaller than those of seeded accessions. Sensory analysis indicated ‘Jawa 1’ seedless accessions have superior quality based on hedonic and scale quality test.
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Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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