Penelitian yang dilakukan pada 3 provenan dan 4 ras lahan cendana (Santalum album Linn.) penyusun pertanaman uji di Wanagama ini bertujuan untuk mengetahui pengaruh aspek biologi reproduksi yaitu pembungaan dan mekanisme penyerbukan terhadap sistem perkawinan dan produksi biji. Parameter pembungaan, mekanisme penyerbukan, dan produksi biji diamati berdasar metode Ghazoul, Owens dkk dan Jones dan Little. Variasi genetik dan sistem perkawinan dihitung menggunakan 2 pendekatan, yaitu analisis isozim dan penyerbukan terkendali. Penyerbukan terkendali meliputi penyerbukan sendiri, alam dan silang resiprokal yang dilakukan secara diallel cross. Analisis isozim dilakukan terhadap daun juvenil mengikuti prosedur elektroforesis gel polyacrilamide vertikal berdasar metode David-Ornstein dengan 3 sistem enzim yaitu SHD (E.C. 1.1.1.25.), EST (E.C. 3.1.1.) dan DIA (E.C. 2.6.4.3). Dijumpai kesamaan tahapan perkembangan bunga; namun interval waktu setiap tahapan berbeda. Variasi dijumpai pada ukuran dan warna bagian-bagian bunga; ciri kemasakan; waktu tercapainya kemasakan dan longevity organ reproduksi; serta interval waktu anthesis. Seluruh provenan/ras lahan bertipe protandri dikogami dan berstruktur heteranthery. Provenan/ras lahan yang berbunga melimpah tidak selalu menghasilkan buah dan biji melimpah pula; dan keguguran terjadi pada tingkat perkembangan yang berbeda. Teramati 6 jenis serangga yaitu ngengat, kupu-kupu (Lepidoptera), lalat (Diptera), semut, lebah dan tawon (Hymenoptera) yang berinteraksi dengan bunga. Fase pembungaan menentukan jenis dan kelimpahan pengunjung bunga melalui pengaruhnya terhadap ketersediaan atraktan primer (tepung sari dan nektar) dan sekunder (warna perigonium dan kepala sari). Preferensi pengunjung terhadap provenan/ras lahan tertentu lebih dipengaruhi oleh atraktan sekunder. Crossing ability tertinggi dijumpai pada ras lahan Karangmojo dan terendah pada Wanagama. Nilai s dari penyerbukan terkendali berkisar mulai sangat rendah hingga sangat tinggi; dengan depresi silang-dalam sangat tinggi (0,785 hingga 1). Analisis isozim memperoleh nilai He 0,287 hingga 0,409; dan Ho 0,392 hingga 0,558; dengan HT 0,403 dan FIS - 0,083. Variasi genetik yang tinggi (HT=0,403) sebagian besar berada dalam populasi (HS=0,366). Variasi genetik antar populasi sangat rendah (DST=0,037). Nilai GST menunjukkan hanya 9,2% berasal dari variasi antar populasi. Standard Nei’s genetic distance menunjukkan bahwa Buat dan Netpala berkerabat terdekat; dan berkerabat dekat pula dengan Karangmojo dan Bromo. Wanagama berkerabat terdekat dengan Imogiri dan Tilomar. Analisis MLTR mengindikasikan tingginya perkawinan silang di alam, pada tingkat multilokus (tm 0,970 hingga 0,983) maupun lokus tunggal (ts 0,883 hingga 0,932). Nilai s (selfing rate) teramati sangat rendah (0,017 hingga 0,030); demikian pula nilai rfert (0,058 hingga 0,065); biparental inbreeding (0,050 hingga 0,087) dan koefisien inbreeding (- 0,200). Depresi silang-dalam berkisar antara sedang (0,380) hingga tinggi (0,683). Nilai rpm memiliki kisaran sangat rendah (0,036) hingga sedang (0,300). Nilai Ne sangat bervariasi (4 hingga 28 butir tepung sari). Variasi tertinggi genotip keturunan diperoleh dari provenan Tilomar, yang 61% keturunannya memiliki genotip berbeda dibanding induk betinanya; diikuti oleh ras lahan Wanagama, Imogiri dan Karangmojo (40 hingga 45%). Adapun Bromo, Buat dan Netpala menghasilkan variasi genotip yang lebih rendah (33 hingga 37%).

Research on several provenances and land races of Sandalwood (Santalum album Linn., Santalaceae) planted at provenance trial in Wanagama aimed to identify the effect of reproductive biology aspects including flowering and pollination mechanisms on its mating systems and seed production. Parameters on flowering, pollination mechanisms, and seed production were measured based on Ghazoul, Owens et al, and Jones and Little methods. Genetic variation and mating systems were analysed based on 2 approaches, isozyme analyses and artificial controlled pollination. Controlled pollination was done by conducting a diallel cross resiprocal self, cross and open pollination. Isozyme analyses on juvenile shoots was done following vertical polyacrilamide slab gel electrophoresis based on David-Ornstein method with 3 enzyme systems: SHD (E.C. 1.1.1.25.), EST (E.C. 3.1.1.) and DIA (E.C. 2.6.4.3). There were similarity on the flowering stages of development, but differences were found on timing interval of each stage. There were variation found on size and color of flower parts, maturity characteristics, time of maturity and longevity of sexual organs, and timing interval of anthesis. All of provenances and landraces were both protandry dichogamy and heteranthery. Provenances/land races with abundant flowers were not always found as the best producer of fruits and seeds. Abortion were took place at the different developmental phase for each provenances/land races. There were 6 types of insect visiting flowers: moths, butterflies (Lepidoptera), flies (Diptera), ants, bees and wasps (Hymenoptera). Flowering phases affect the kind and amount of flower visitors by its role on primary (pollen and nectar) and secondary (color of perigonium and mature anthers) attractant availability. Visitor’s preference on certain provenances/land races were affected more by secondary attractant. Highest crossing ability was found on Karangmojo land race while Wanagama was the lowest. The s value gotten from artificial controlled pollination ranged from very low to very high; while inbreeding depression was very high (0,785 to 1). Isozyme analyses resulting to He 0,287 to 0,409; and Ho 0,392 to 0,558; while HT was 0,403 and FIS was - 0,083. High genetic variation (HT=0,403) was mostly found within population (HS=0,366); while variation between population was very low (DST=0,037). The GST showed that only 9,2% of variation exist between population. Standard Nei’s genetic distance showed closest inheritance between Buat and Netpala; and both provenances were close to Karangmojo and Bromo as well. Wanagama was closest to Imogiri and Tilomar. MLTR analyses indicating a high rate of outcrossing both at multi (tm 0,970 to 0,983) and single (ts 0,883 to 0,932) locus. The s value (selfing rate) was very low (0,017 to 0,030); and the same case were also found on rfert (0,058 to 0,065); biparental inbreeding (0,050 to 0,087) and inbreeding coefficient (- 0,200). Inbreeding depression ranged from intermediate (0,380) to high (0,683). The correlation of paternity (rpm) ranged from low (0,036) to intermediate (0,300). The Ne vas varied from 4 to 28 pollen grains. Highest variation on offspring genotype was found on Tilomar, in which 61% proportion of offsprings perform the different genotype compared to its maternal parent; followed by Wanagama, Imogiri and Karangmojo (40 to 45%); while Bromo, Buat and Netpala were the lowest (33 to 37%).

Kata Kunci : cendana, sistem perkawinan, biologi reproduksi, pembungaan, mekanisme penyerbukan, produksi biji, variasi genetik, provenan dan ras lahan, sandalwood, mating systems, reproductive biology, flowering, pollination mechanisms, seed production, genetic variat