Model Hydrotime dan Hubungannya dengan Uji Vigor pada beberapa Konsentrasi PEG dan Varietas Padi (Oryza sativa L.) Inbrida
Abstract
Model hydrotime menggambarkan hubungan kadar air benih dengan waktu imbibisi yang terjadi sebagai respon terhadap potensial air. Penelitian bertujuan
mendapatkan pola kadar air benih pada beberapa konsentrasi PEG 6000 dan hubungannya dengan uji vigor benih pada beberapa varietas padi inbrida. Penelitian dilakukan berdasarkan 2 percobaan yaitu percobaan 1 (pembuatan pola kadar air) dan percobaan 2 (uiji mutu fisiologis benih). Kedua percobaan menggunakan 3 varietas padi inbrida yaitu Inpari 40, Inpara 8, dan Biobestari. Kedua percobaan menggunakan 4 taraf konsentrasi PEG 6000 yaitu P0 = 0%, P1 = 5%, P2 = 10%, dan P3 = 20%, yang secara berurutan setara dengan potensial air (?) 0 MPa, -0,13 MPa, -0,4 MPa, dan -0,6 MPa. Percobaan 1 menggunakan Rancangan Kelompok Lengkap Teracak (RKLT) 1 faktor yaitu konsentrasi PEG 6000. Pembuatan pola kadar air (model hydrotime) dilakukan dengan mengukur kadar air benih setiap 4 jam selama 104 jam. Percobaan 2 menggunakan rancangan faktorial dua faktor secara Rancangan Kelompok Lengkap Teracak (RKLT). Faktor pertama adalah varietas padi dan faktor kedua adalah konsentrasi PEG 6000. Pengamatan dilakukan sebanyak 3 ulangan. Pola kadar air (model hydrotime) pada varietas padi Inpari 40, Inpara 8, dan Biobestari ditandai dengan 3 fase, yaitu fase I (0 –28 jam), fase II (28–84 jam), dan fase III (> 84 jam). Fase I ditandai dengan kenaikan kadar air yang signifikan, fase II ditandai kadar air yang cenderung stabil, dan fase III ditandai kadar air yang meningkat kembali. Pola kadar air pada konsentrasi PEG 6000 10% dan 20% mengakibatkan benih mengalami fase II yang lebih panjang. Perlakuan konsentrasi PEG 6000 20% berpengaruh nyata pada semua peubah dikarenakan fase II yang lebih panjang yaitu >104 jam. Konsentrasi PEG 6000 10% dan 20%
membentuk model hydrotime yang potensial untuk menduga vigor benih spesifik kekeringan. Hydrotime model describes the relationship between seed water content and imbibition time which occurs in response to water potential. The research aims to obtain seed water content patterns at several PEG 6000 concentrations and their relationship with seed vigor tests on several inbred rice varieties. The research was carried out based on 2 experiments, namely experiment 1 (patterning water content) and experiment 2 (testing the physiological quality of seeds). Both experiments used 3 inbred rice varieties, namely Inpari 40, Inpara 8, and Biobestari. Both experiments used 4 levels of PEG 6000 concentration, namely P0 = 0%, P1 = 5%, P2 = 10%, and P3 = 20%, which respectively are equivalent to water potential (?) 0 MPa, -0.13 MPa, - 0.4 MPa, and -0.6 MPa. Experiment 1 used a Randomized Complete Block Design (RCBD) with 1 factor, namely the concentration of PEG 6000. Making a water content pattern (hydrotime model) is done by measuring the water content of the seeds every 4 hours for 104 hours. Experiment 2 used a twofactor factorial design using a Randomized Complete Block Design (RCBD). The first factor is rice variety and the second factor is the concentration of PEG 6000. Observations were carried out in 3 repetitions. Water content pattern (model hydrotime) in the rice varieties Inpari 40 Inpara 8, and Biobestari are characterized by 3 phases, namely phase I (0 –28 hours), phase II (28 – 84 hours), and phase III (> 84 hours). Phase I is characterized by a significant increase in water content, phase II is characterized by water content which tends to be stable, and phase III is characterized by water content which increases again. The pattern of water content at PEG 6000 concentrations of 10% and 20% resulted in the seeds experiencing a longer phase II. The 20% PEG 6000 concentration treatment had a significant effect on all variables because phase II was longer, namely >104 hours. PEG 6000 concentrations of 10% and 20% form the model hydrotime which has the potential
to predict drought-specific seed vigor.