Pola Hydrotime dan Uji Mutu Fisiologis Dua Varietas Benih Tomat (Solanum lycopersicum L.) pada Berbagai Konsentrasi PEG 6000

Abstract

Seleksi awal benih tomat tahan kekeringan di persemaian untuk pemuliaan dapat dilakukan dengan pendekatan pola hydrotime. Pola hydrotime dapat menunjukkan pola perkecambahan benih sebagai respons dari potensial air yang ada di lingkungan. Penelitian ini bertujuan memperoleh pola kadar air benih tomat (Solanum lycopersicum L.) berbagai konsentrasi PEG 6000 serta uji mutu fisiologis dua varietas benih tomat pada beberapa konsentrasi PEG 6000. Penelitian dilakukan dengan dua percobaan, yang pertama pembuatan pola kadar air benih dan yang kedua yaitu uji mutu fisiologis dua varietas benih tomat pada berbagai konsentrasi PEG 6000. Rancangan pada kedua percobaan menggunakan Rancangan Kelompok Lengkap Teracak. Percobaan pertama menggunakan satu faktor yaitu konsentrasi PEG 6000 sementara pada percobaan kedua terdapat dua faktor yaitu konsentrasi PEG 6000 dan varietas tomat. Pada konsentrasi PEG 6000 digunakan 4 taraf yaitu P0 = 0%, P1 = 5%, P2 = 10%, dan P3 = 15%, konsentrasi tersebut secara berurutan setara dengan (?) 0 MPa, -0,13 MPa, -0,19 MPa dan -0,41 MPa serta dua taraf varietas yaitu V1 = Niki dan V2 = Rempai. Pengamatan kedua percobaan dilakukan sebanyak 3 ulangan. Pola kadar air (pola hydrotime) dibuat dengan mengukur kadar air benih tomat setiap 4 jam selama 128 jam. Pola hydrotime pada varietas Niki dan Rempai dibagi menjadi 3 fase dan terdapat perbedaan pola kadar air antar perlakuan konsentrasi PEG 6000. Pada perlakuan kontrol, varietas Niki terdiri atas fase I (0-4 jam), fase II (4-52 jam), dan fase III (> 52 jam) serta pada varietas Rempai fase I (0-4 jam), fase II (4-56 jam), dan fase III (> 56 jam). Perlakuan konsentrasi PEG 6000 = 5% membentuk fase II lebih panjang dan menghambat kemunculan radikula. Varietas Rempai relatif lebih tahan terhadap cekaman PEG 6000 dibandingkan varietas Niki yang dibuktikan dengan nilai dari peubah mutu fisiologis lebih tinggi pada setiap perlakuan. Konsentrasi PEG 6000 perlakuan kontrol dan 10% membentuk pola hydrotime yang potensial digunakan sebagai metode penapisan terhadap cekaman kekeringan di persemaian.

Kata kunci: imbibisi, kadar air, penapisan, potensial air

Initial selection of drought-resistant tomato seeds in the nursery for breeding can be carried out using the hydrotime pattern approach. The hydrotime pattern can indicate the germination pattern of seeds as a response to the water potential present in the environment. This study aims to obtain the moisture pattern of tomato seeds (Solanum lycopersicum L.) at various concentrations of PEG 6000 and to test the physiological quality of two varieties of tomato seeds at several concentrations of PEG 6000. The research was conducted with two experiments, the first being the creation of seed moisture content patterns and the second being the physiological quality test of two varieties of tomato seeds at various concentrations of PEG 6000. The design for both experiments used a Randomized Complete Block Design (RCBD). The first experiment used one factor which was the concentration of PEG 6000, while the second experiment had two factors namely the concentration of PEG 6000 and the variety of tomatoes. In the PEG 6000 concentration, 4 levels were used, namely P0 = 0%, P1 = 5%, P2 = 10%, and P3 = 15%, which corresponded respectively to (?) 0 MPa, -0.13 MPa, -0.19 MPa, and -0.41 MPa, along with two levels of varieties namely V1 = Niki and V2 = Rempai. Observations of the second experiment were conducted in 3 replications. The water content pattern (hydrotime pattern) was created by measuring the water content of tomato seeds every 4 hours for 128 hours. The hydrotime pattern in the Niki and Rempai varieties was divided into 3 phases, and there were differences in water content patterns among the treatments of PEG 6000 concentration. In the control treatment, the Niki variety consisted of phase I (0-4 hours), phase II (4-52 hours), and phase III (> 52 hours), while in the Rempai variety, phase I (0-4 hours), phase II (4-56 hours), and phase III (> 56 hours) were observed. Treatments with PEG 6000 concentrations = 5% formed a longer phase II and inhibited the emergence of the radicle. The Rempai variety was relatively more resistant to PEG 6000 stress compared to the Niki variety, as evidenced by higher values of physiological quality parameters in each treatment. The PEG 6000 concentration of the control treatment and 10% formed hydrotime patterns that are potentially used as screening methods for drought stress in nurseries.

Keywords: imbibition, screening, water content, water potential.