Judul: Photothermal Unit Approach for Determination of Development Phases and Harvest Time of Eight Bambara Groundnut (Vigna subterranea L.)
Abstrak: Terbatasnya benih bermutu merupakan salah satu permasalahan yang sering dihadapi oleh petani kacang Bambara. Benih mencapai mutu maksimum saat masak fisiologis. Waktu masak fisiologis tanaman berbeda pada setiap lokasi penanaman dan faktor lingkungan yang mempengaruhinya, terutama suhu harian dan lama penyinaran sinar matahari. Photothermal unit merupakan konsep yang menjelaskan hubungan antara perkembangan tanaman dengan suhu dan lama penyinaran. Penelitian ini bertujuan mempelajari photothermal unit tiap fase perkembangan serta waktu panen terbaik delapan lanras kacang Bambara. Rancangan percobaan yang digunakan yaitu rancangan kelompok lengkap teracak satu faktor yakni lanras yang dilakukan pada dua lokasi dengan masing-masing 5 lima taraf dan 3 taraf berupa lanras tanaman. Lokasi percobaan pertama beada pada Kebun Percobaan Cikabayan dengan lima taraf : Bogor, Sukabumi, Sumedang testa hitam kecil, Sumedang testa cokelat. Lokasi kedua di Kebun Percobaan Sawah Baru dengan tiga taraf : Sumedang testa hitam besar, Tasikmalaya testa hitam kecil, Tasikmalaya testa hitam besar, dan Gresik. Hasil penelitian menunjukkan bahwa setiap lanras tanaman kacang Bambara membutuhkan waktu yang berbeda untuk mencapai setiap fase perkembangan dan akumulasi nilai photothermal unit nya. Nilai photothermal unit yang dibutuhkan untuk mencapai waktu panen lanras Bogor, Gresik, dan Tasikmalaya testa hitam kecil 10710 ℃ d h, lanras Sukabumi 10760 ℃ d h, Sumedang testa hitam kecil dan Tasikmalaya testa hitam besar 10342,72 ℃ d h, lanras Sumedang testa cokelat 11540 ℃ d h dan lanras Sumedang testa hitam kecil 11756,7 ℃ d h., Lack of quality seeds is one of the problems often faced by Bambara groundnut farmers. Seed reaches its maximum quality at physiological maturity. The physiological maturity time is different for each planting location and environmental factors that influence it, especially daily temperature and duration of irradiation. A photothermal unit is a concept that explains relationship between plant development, temperature, and duration of irradiation. This experiment aimed to study the photothermal unit of each developmental phase and the best harvest time for eight landraces of Bambara groundnut. The experimental design used was a one-factor randomized complete block design, namely landraces conducted at two locations, each with five levels and three levels consisting of plant varieties. The first experiment location was at the Cikabayan Experimental Garden with five levels: Bogor, Sukabumi, small Sumedang black testa, Sumedang brown testa. The second location was at the Sawah Baru Experimental Garden with three levels: large Sumedang black testa, small Tasikmalaya black testa, and large Tasikmalaya black testa. The results showed that each landrace of the Bambara groundnut plant required a different time to reach the stage of development and to accumulate the photothermal unit requirement. The photothermal unit needed to achieve the harvest time of the Bogor, Gresik, and small Tasikmalaya black testa were 10710 ℃ d h, Sukabumi 10760 ℃ d h, small Sumedang black testa and large Tasikmalaya black testa 10342.72 ℃ d h, Sumedang brown testa 11540 ℃ d h and small Sumedang black testa 11756.7 ℃ d h.
Keyword: daily temperature, duration of irradiation, physiological maturity, seed quality, yield component