STUDI PERKEMBANGAN MORFOLOGI PADA FASE VEGETATIF DAN REPRODUKTIF TIGA KULTIVAR RUMPUT GAJAH (Pennisetum purpureum Schum)

BUDIMAN, Prof. Ir. R. Djoko Soetrisno, M.Sc, PhD.,

2012 | Disertasi | S3 Ilmu Peternakan

Penelitian ini bertujuan untuk mengamati perkembangan morfologi, karakteristik, produksi dan kualitas rumput gajah kultivar Taiwan, King dan Mott, serta mengamati perubahan total non-structural carbohydrates (TNC) rumput gajah kultivar Taiwan. Penelitian tahap pertama dan kedua menggunakan rancangan percobaan pola faktorial. Tiga kultivar (Taiwan, King dan Mott) dan dua fase pertumbuhan (vegetatif dan reproduktif) digunakan untuk menentukan indeks mean stage count (MSC), karakateristik pertumbuhan, produksi bobot kering (Bk), protein kasar (PK), neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), kecernaan bahan kering (KcBK), kecernaan bahan organik (KcBO) dan kecernaan NDF (KcNDF). Rancangan percobaan pola faktorial, dua fase pertumbuhan (vegetatif dan reproduktif ) dan 4 pertumbuhan kembali (0, 4, 8 dan 12) hari setelah defoliasi dan 3 ulangan untuk menentukan TNC pangkal batang dan anakan dan TNC akar rumput gajah kultivar Taiwan. Hasil penelitian pertama menunjukkan bahwa indeks MSC dan SMSC kultivar Taiwan lebih tinggi dibanding kultivar Mott, tetapi MSC dan SMSC kultivar Taiwan tidak berbeda dengan kultivar King dan kultivar Mott tidak berebeda dengan kultivar King. Indeks MSC dan SMSC meningkat pada fase reproduktif. Panjang ruas dan diameter batang lebih tinggi pada kultivar Taiwan dan King dibanding dengan kultivar Mott. Interaksi antara kultivar dengan fase pertumbuhan ditemukan pada rasio daun batang, tinggi tanaman dan produksi bahan kering. Rasio daun batang tertinggi pada interaksi kultivar dengan fase pertumbuhan yaitu: Mott-vegetatif, Mott-reproduktif, King-vegetatif, Taiwanvegetatif, King-reproduktif dan Taiwan reproduktif. Tinggi tanaman tertinggi pada interaksi kultivar dengan fase pertumbuhan yaitu:Taiwan-reproduktif, Kingreproduktif, Taiwan vegetatif, King-vegetatif, Mott-reproduktif dan Mott-vegetatif. Produksi bahan kering tertinggi pada interaksi kultivar dengan fase pertumbuhan yaitu:Taiwan-reproduktif, King-reproduktif, Mott-reproduktif, Taiwan-vegetatif, King-vegetatifdan Mott-vegetatif. Hasil penelitian kedua menunjukkan bahwa kandungan protein kasar tertinggi terdapat pada kultivar Mott, sedangkan NDF, ADF dan ADL tertinggi terdapat pada kultivar Taiwan dan King. Kandungan NDF, ADF, ADL meningkat dan protein kasar menurun pada fase reprroduktif. Terdapat interaksi antara kultivar dengan fase pertumbuhan terhadap KCBK, KcBO dan KcNDF. KcBK dan KcBO tertinggi terdapat pada interaksi kultivar dengan fase pertumbuhan yaitu: Mott-vegetatif disusul oleh Mott-reproduktif, King-vegetatif, Taiwan-vegetatif, King-reproduktif dan Taiwan-reproduktif, sedangkan pada KcNDF pada kombinasi Mott-vegetatif disusul oleh Mottreproduktif, King-vegetatif, Taiwan-vegetatif, Taiwan-reproduktif dan Kingreproduktif. Penelitian ketiga menunjukkan bahwa terdapat interaksi antara fase pertumbuhan dengan pertumbuhan kembali terhadap TNC pangkal batang dan anakan dan TNC akar. Kandungan TNC pangkal batang dan anakan pada fase vegetatif lebih rendah dibanding dengan fase reproduktif. Terjadi penurunan TNC pada pangkal batang dan anakan pada fase vegetatif maupun pada fase reproduktif sampai hari ke- 12. Kandungan TNC akar pada fase vegetatif lebih rendah dibanding dengan fase reproduktif. Terjadi penurunan TNC akar pada fase vegetatif maupun pada fase reproduktif. Penurunan TNC akar pada fase vegetatif berlangsung lebih lambat dan mencapai nilai minimum pada hari ke- 7,93; kemudian mulai meningkat pada hari ke-12. Kejadian sebaliknya pada fase reproduktif, penurunan TNC masih tetap berlangsung sampai pada hari ke- 12.

This study aims to observe the development of morphology, characteristic, production and quality of napier grass of Taiwan, King and Mott cultivars, and observes the changes in total non-structural carbohydrates (TNC) of napier grass of Taiwan cultivars. The first and second stages of the study used factorial pattern experiment design. Three cultivars (Taiwan, King and Mott) and two growth stages (vegetative and reproductive) were used to determine the mean stage count (MSC) index, growth characteristic, production of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), dry matter digestibility (DMD), organic matter digestibility (OMD) and NDF digestibility (NDFD). The factorial pattern experiment design, the two growth stages (vegetative and reproductive) and 4 regrowth of 0, 4, 8 and 12 days after defoliation and three replications were used to determine TNC of the stem bases and shoots and TNC of napier grass roots of Taiwan cultivar. The first study results showed that the MSC and SMSC index of Taiwan cultivar were higher than those of Mott cultivar, but the MSC and SMSC of Taiwan cultivar were not different than those of King cultivar, and those of Mott cultivar were not different than those of King cultivar. The MSC and the SMSC index increased in the reproductive stage. The internode lengthes and stem diameters of Taiwan and King cultivars were higher than those of Mott cultivar. The interaction between cultivars and growth stages was found in the leaf stem ratio, plant height and dry matter production. Leaf stem ratio was highest in the interaction of cultivar and growth stage, namely: vegetative-Mott, reproductive- Mott, vegetative-King, vegetative-Taiwan, reproductive-King and reproductive- Taiwan. The highest plant height in the interaction of cultivar and growth stage, namely: reproductive-Taiwan, reproductive-King, vegetative Taiwan, vegetative- King, reproductive-Mott and vegetative-Mott. The highest dry matter production in the interaction of cultivar and growth stage, namely: reproductive-Taiwan, reproductive-King, reproductive-Mott, vegetative-Taiwan, vegetative-King dan vegetative-Mott. The second study results showed that the highest content of crude protein was in Mott cultivar, whereas NDF, ADF and ADL were highest in Taiwan and King cultivars. The contents of NDF, ADF, ADL increased and crude protein decreased in reproductive stage. There is interaction between the cultivars and the growth stage of DMD, OMD and NDFD. The highest OMD and DMD were found in interaction of the cultivars and the growth stages, namely: vegetative-Mott, followed by the reproductive-Mott, vegetative-King, vegetative- Taiwan, reproductive-Taiwan and reproductive-King, whereas in NDFD-Mott was in vegetative-Mott combination followed by reproductive-Mott, vegetative-King, vegetative-Taiwan, reproductive-Taiwan and reproductive-King. The third study showed that there was interaction between the growth stage and the regrowth of TNC of base of stems and shoots and root TNC. TNC content of base of stems and shoots in the vegetative stage was lower than the reproductive stage. There were TNC declines in base of stems and shoots in vegetative stage and reproductive stage until day-12. Root TNC in vegetative stage was lower than that in reproductive stage. There were declines in root TNC in vegetative stage and reproductive stage. The decrease of root TNC in vegetative stage was slower and reached a minimum value on day 7.93; then began to increase on day 12. The reverse was in reproductive stage, the decline in TNC still going until on day-12.

Kata Kunci : Fase reproduktif, indeks MSC, kecernaan, phase vegetatif, rumput gajah, total karbohidrat non-struktural