Respon Pertumbuhan dan Kualitas Buah Tiga Varietas Stroberi (Fragaria chiloensis L.) Terhadap Perlakuan Kitosan dan Pemangkasan Buah

Abstract

The purposes of the following research were to obtain several different varieties of Strawberry plants based on the soil environment, especially at Karo district area; to increase the number of fruits and bigger fruits size in each Strawberry plant; to determine the chitosan concentration to produce a better fruits quality before and after the harvest and prolong the livelihood of the strawberry fruits in storage. The research was conducted in the area of Fruit Research Facility (BPTB) at Karo district area where the land elevation was ± 800 m dpl. The research was consisted of two researches, namely: The research I was aimed to response application of chitosan and fruit pruning on growth and production of 3 varieties of strawberries (Fragaria chiloensis L.), by applying Chitosan and fruit trimming techniques; Research II was aimed to chitosan immersion on 3 varieties of strawberries after harvest. Research I was conducted by utilizing Split-split Plot Design (SSPD) location, where the strawberry varieties plants was located at the main area, the strawberry plants with chitosan concentration was located at the second area and the strawberry plants with fruits trimming techniques was located at the third area. There were three (3) varieties used, namely Local Strawberry Variety, Candler Strawberry Variety and California Strawberry Variety. The activities on Research I was then continued to Research II by utilizing Randomized Block Design (RBD) which consisted of three (3) different activities. The first activity was to grow the strawberry variety. The second activity was to grow the strawberry varieties and spray the chitosan in the field and then dipped the strawberry fruits into the chitosan concentration after the harvest. The last activity was to grow the strawberry varieties with fruits trimming. The spraying and dipping of chitosan was carried out with four (4) different levels of concentration, namely: No chitosan, 50cc per Liter of water, 100cc per Liter of water and 150cc per Liter of water. The fruits trimming was also carried out in 4 different ways, namely: No fruits trimming, trimming with 2 (two) fruits left over on the strawberry plant, trimming with 4 (four) fruits left over on the strawberry plants and trimming with 6 (six) fruits left over on the strawberry plants. The result of the research showed that the variety of the strawberry it self significantly influenced the growth of the strawberry in general. The combination interaction between the strawberry variety and the spraying of chitosan also influenced the strawberry growth. The combination interaction between the strawberry variety and the fruits trimming also influenced the strawberry growth. However, the combination interaction among the strawberry variety and the spraying of chitosan and the fruits trimming did not encourage the strawberry growth, nor the fruit quality after harvest. The local strawberry variety produced bigger and wider leaves and the higgest dried plant weights. The candler strawberry variety produced the higgest weight of fresh fruits. The California strawberry variety produced the highest growth and the highest clean assimilation. The trimming with two (2) fruits left over and the chitosan spraying of 50-150cc per Liter of water, produced the best growth in all varieties of strawberry. The quality of the strawberry fruits was influenced by the combination of the interaction between the strawberry variety and the sprying of chitosan, while the combination interaction of the strawberry variety and the spraying of chitosan together with the fruits trimming only influenced the hardness of the strawberry fruits. However, the highest fruits hardness, vitamin C and water; and the lowest fruits weight decreased was only occurred on the local strawberry variety which was dipped into 150cc per Liter of water. Other result showed that the candler strawberry variety sprayed with 50-150cc per Liter of water produced the highest total content of acid and liquid fruits with the lowest in respiration growth. The result of the research also showed that the local strawberry variety was suited for the soil of Karo district area. This was due to the fact that the local strawberry growth was better than the growth of other strawberry varieties. The Candler strawberry variety on theother hand was better in fruits quality after the harvest. The fruits trimming together with the spraying of chitosan and continued with fruits dipped after harvest in a chitosan concentration of 100-150cc per Liter of water produced a better fruits in terms of growth parameters and the strawberry fruits storage.

Penelitian ini bertujuan untuk mendapatkan varietas stroberi yang sesuai di lingkungan pertanaman, khususnya di Kabupaten Karo, mendapatkan jumlah buah pertanaman dengan ukuran buah yang besar, mendapatkan konsentrasi kitosan yang menghasilka kualitas buah prapanen dan pascapanen yang baik, serta umur simpan yang lebih lama. Penelitian dilaksanakan di kebun percobaan Balai Penelitian Tanaman Buah (BPTB) terletak pada ketinggian ± 800 m dpl. Penelitian terdiri dari 2 tahap, yaitu penelitian I (Respon Aplikasi Kitosan dan Pemangkasan Buah Terhadap Pertumbuhan dan Produksi 3 Varietas Stroberi (Fragraria chiloensis L.)), dan penelitian II (Pencelupan Kitosan Pada Buah 3 Varietas Stroberi Setelah Panen). Penelitian tahap I menggunakan Rancangan Petak-Petak Terbagi (RPPT) dengan varietas sebagai anak petak utama, aplikasi kitosan sebagai anak petak dan pemangkasan buah sebagai anak-anak petak. Perlakuan pada tahap I ini dilanjutkan ke penelitian tahap II dengan menggunakan Rancangan Acak Kelompok (RAK) faktorial, yang terdiri dari 3 faktor perlakuan, yaitu: faktor I berupa varietas, faktor II perlakuan penyemprotan kitosan di lapangan yang dilanjutkan dengan perlakuan pencelupan buah setelah dipanen dengan kitosan dan faktor III yaitu pemangkasan buah. Perlakuan varietas terdiri dari 3 taraf perlakuan, yaitu Varietas Lokal, Candler dan California. Perlakuan penyemprotan dan pencelupan kitosan terdiri dari 4 taraf konsentrasi yaitu tanpa kitosan, aplikasi kitosan 50 cc/L air, 100 cc/L air dan 150 cc/L air sedangkan perlakuan pemangkasan buah terdiri dari 4 taraf perlakuan yaitu tanpa pemangkasan buah, dipangkas dengan sisa buah 2, dipangkas dengan sisa buah 4 dan dipangkas dengan sisa buah 6. Hasil penelitian menunjukkan secara umum varietas memberikan pengaruh yang lebih besar terhadap pertumbuhan tanaman. Interaksi antar perlakuan yang berpengaruh secara nyata terhadap pertumbuhan tanaman adalah interaksi antara varietas dan pemangkasan serta interaksi antara varietas dan penyemprotan kitosan, sedangkan interaksi antar ketiga perlakuan memberikan pengaruh yang berbeda tidak baik terhadap pertumbuhan tanaman maupun kualitas pascapanen buah. Varietas lokal memberikan luas daun dan bobot kering tanaman yang tertinggi, tetapi bobot buah segar tertinggi diperoleh pada varietas candler sedangkan laju asimiliasi bersih dan laju tumbuh relatif tertinggi diperoleh pada varietas california. Pemangkasan buah dengan sisa 2 buah dan penyemprotan dengan kitosan 50-150 cc/L air untuk semua varietas memberikan hasil pertumbuhan tanaman yang terbaik. Mutu buah stroberi dipengaruhi oleh interaksi antara varietas dan aplikasi kitosan, sedangkan interaksi antara varietas dan kitosan dengan pemangkasan buah hanya memberikan pengaruh terhadap kekerasan buah. Kekerasan buah, kadar vitamin C, kadar air tertinggi serta susut bobot terendah diperoleh pada buah dari varietas lokal dengan pencelupan 150 cc/L air, tetapi total padatan terlarut dan kadar serta tertinggi serta total asam dan laju respirasi terendah diperoleh pada buah dari varietas candler dan penyemprotan kitosan 501-50 cc/L air. Hasil penelitian menunjukkan bahwa varietas lokal lebih sesuai untuk pertanaman di daerah Tanah Karo yang ditunjukkan dengan pertumbuhan tanaman yang lebih baik, tetapi mutu buah pascapanen yang baik diperoleh dari varietas candler. Pemangkasan buah dengan sisa buah dan penyemprotan kitosan dipertanaman yang dilanjutkan dengan pencelupan buah pascapanen dengan konsentrasi 100-150 cc/L air memberikan hasil terbaik untuk parameter pertumbuhan dan penyimpanan buah stroberi.