PERUBAHAN BIOLOGIS DAN FISIOLOGIS SEBAGAI INDIKATOR MASAK BENIH KAKAO HIBRIDA - BAHARUDIN BAHARUDIN; M.R. SUHARTANTO; S. ILYAS; A. PURWANTARA (Pusat Penelitian dan Pengembangan Perkebunan, 2011)
ABSTRAKProgram pengembangan dan rehabilitasi tanaman kakao membutuh-kan benih bermutu. Mutu benih antara lain ditentukan oleh saat panenyang tepat, terutama berhubungan dengan masak fisiologis. Beberapaindikator penting yang berkaitan dengan masak fisiologis benih adalahkarakteristik biologis dan fisiologis. Penelitian telah dilaksanakan diKebun Induk Benih Pusat Penelitian Kopi dan Kakao (Puslitkoka) Jember,Laboratorium Fisika dan Laboratorium Ilmu dan Teknologi Benih IPB,serta Rumah Kaca Balai Penelitan Bioteknologi Perkebunan Indonesia,Bogor pada bulan Februari-September 2008. Penelitian ini bertujuan untuk(1) mempelajari perubahan biologis dan fisiologis selama perkembanganbenih kakao hibrida, (2) mengetahui hubungan antar berbagai karakterbiologis dan fisiologis benih yang mencerminkan mutu benih, dan (3)menentukan saat panen yang tepat benih kakao hibrida TSH 858 xSca 6 dan ICS 60 x Sca 6. Benih yang digunakan berasal dari hasilpersilangan buatan antara kakao TSH 858 x Sca 6 dan ICS 60 x Sca 6.Umur panen benih yang digunakan dalam penelitian adalah 120, 135, 150,165, dan 180 hari yang dihitung saat setelah antesis, dan setiappengamatan diulang 4 kali. Analisis data disajikan dalam bentuk grafikdengan data primer ditambah standar deviasi dalam program Excel danuntuk mengetahui hubungan dari masing-masing karakter mutu benihdilakukan ”analisis path” menggunakan SAS dari Windows v 9.1. Hasilpenelitian menunjukkan dua fase perkembangan benih. Fase perkem-bangan hingga masak fisiologis (fase 1) dan fase setelah masak fisiologis(fase 2) kakao hibrida TSH 858 x Sca 6 dan ICS 60 x Sca 6. Masakfisiologis benih kakao hibrida TSH 858 x Sca 6 tercapai pada saat 150HSA dan ICS 60 x Sca 6 pada 165 HSA. Daya kecambah, indeks vigor,K CT -R, T 50 , bobot basah dan bobot kering benih, karotenoid dan antosianinbenih dan buah, jumlah daun, dan tinggi bibit dari benih kakao hibridaTSH 858 x Sca 6 dan ICS 60 x Sca 6 mencapai maksimum pada saatmasak fisiologis dan menurun pada fase kedua. Selama periodeperkembangan benih terjadi penurunan total klorofil benih dan buah,sedangkan warna buah kuning mengalami peningkatan. Karakter yangberhubungan langsung dengan mutu benih pada saat masak fisiologisbenih kakao hibrida TSH 858 x Sca 6 dan ICS 60 x Sca 6 adalah warnabuah kuning, indeks vigor, total klorofil benih dan buah, karotenoid danantosianin benih, T 50 , tinggi bibit, K CT -R, dan bobot kering benih.Kata kunci: Theobroma cacao, biologi benih, fisiologi benih, karakteristikbenih, mutu benihABSTRACTBiological and Physiological Changes as Indicator ofMaturity of Hybrid Cacao SeedThe development and rehabilitation programs of cacao need highquality seeds. The high quality of cacao seeds is influenced by seedsphysiological maturity and harvesting time. Several important indicatorsrelated to the seed physiological maturity are biological and physiologicalcharacters. The research objectives were: (1) to study biological andphysiological changes during of seed development, (2) to study on thecorrelation of various characteristics related with seeds physiology andquality, (3) to determine the most appropriate harvesting time for hybridcacao seed of TSH 858 x Sca 6 and ICS 60 x Sca 6. The research wasconducted at Coffee and Cacao Research Institute of Indonesia(Puslitkoka) in Jember, IPB Biophysics and Seeds and TechnologyLaboratory and Biotechnology Research Institute for Estate CropsIndonesia glass house in Bogor from February to September 2008. Theseeds were originated from hand pollination of TSH 858 vs Sca 6 and ICS60 vs Sca 6 hybrids from Puslitkoka Jember. The seeds for this researchwere harvested on: 120, 135, 150, 165, and 180 days after anthesis (DAA);with four replications each. Data were analyzed and presented as graphs,standard deviation in excel; while the relationship of each character ofseeds quality was determined using path analysis by SAS for Windows v.9.1. The results showed that the seed physiological changed on two phasesduring its development. The first phase started from seeds development upto physiological maturity for TSH 858 x Sca 6 and as well ICS 60 x Sca 6hybrids, and second phases started after physiological maturity. Thephysiological maturity of each seeds is 150 DAA for TSH 858 x Sca 6 and165 DAA for ICS 60 x Sca 6 hybrids. Seed germination percentage, vigorindex, germination rate (K CT -R and T 50 ), wet and dry weight of seed, seedsand fruits carotenoid content, seed and fruit anthocyanin content, numberof leaves, and height of seedling reached maximum when seed achievedphysiological maturity and decreased afterward. During seed development,there was decreasing of seeds and fruits chlorophyll content and increasedfor the yellow color of fruit. The characters which showed directcorrelation with seeds quality during seed development of TSH 858 x Sca6 and ICS 60 x Sca 6 hybrids are: yellow color of fruit, vigor index,chlorophyll content for seeds and fruit, seed carotenoid and anthocyanincontent, germination rate (T 50, K CT -R), seedling height and seed dry weight.Key words: Theobroma cacao, seed biological, seed physiological, seedcharacteristic, seed quality