GENETIKA UMUR PANEN DAN HUBUNGANNYA DENGAN HASIL DAN KOMPONEN HASIL TANAMAN KEDELAI

Gatut Wahyu Anggoro Susanto, Ir.,MP., Prof. (Emer.) Dr. Ir. Woerjono Mangoendidjojo, M.Sc.

2014 | Disertasi | S3 Ilmu Pemuliaan Tanaman

Aksi gen yang mengendalikan karakter sangat penting untuk diketahui, terutama berkaitan dengan efektivitas penerapan seleksi untuk mendapatkan karakter yang diinginkan. Penelaahan genetika umur panen tanaman kedelai memiliki arti penting dalam program pemuliaan, dan untuk tanaman kedelai di Indonesia belum banyak dipelajari. Tujuan penelitian adalah memperoleh informasi tentang genetika umur panen, diperoleh tetua dan kombinasi persilangan yang prospektif untuk perbaikan umur panen ke arah umur genjah, serta diketahui keeratan hubungan antara umur panen dengan hasil biji dan komponen hasil pada populasi F2 tanaman kedelai. Bahan penelitian yang digunakan lima varietas kedelai, yaitu Nanti (berumur panen sangat dalam), Dempo (berumur panen dalam), Dieng (berumur panen sedang), serta Grobogan dan Malabar (berumur panen genjah). Penelitian dilakukan dua tahap yaitu : pertama adalah pembentukan populasi tanaman terdiri dari F1 (persilangan P1×P2) dan F1 resiproknya/F1r (persilangan P2×P1), populasi bersegregasi F2 (selfing dari F1), silang balik atau backcross (BC1.1) (persilangan F1×P1) dan silang balik atau backcross (BC1.2) (persilangan F1×P2). Pelaksanaan penelitian tahap pertama dimulai Maret 2008 hingga Juni 2009, di Balitkabi Malang. Tahap kedua adalah penelitian lapangan mempelajari genetika pewarisan umur panen. Pelaksanaan penelitian tahap kedua dimulai Juli 2009 hingga Juni 2010 di Kebun Percobaan Jambegede, Kabupaten Malang, Jawa Timur. Hasil penelitian menunjukkan bahwa pewarisan umur panen kedelai persilangan Nanti×Dempo, Nanti×Dieng, Nanti× Grobogan, Dempo×Grobogan, Dempo× Dieng, Dieng×Grobogan dan Grobogan×Malabar diwariskan melalui inti sel, dengan aksi gen yang berbeda. Pola pewarisan umur panen kedelai tergantung pasangan tetua yang disilangkan. Persilangan umur panen genjah (Malabar) dengan umur panen dalam (Dempo) pola segregasinya menunjukkan epistasis dominan dan resesif (13 genjah : 3 dalam). Persilangan umur panen sedang (Dieng) dengan umur panen genjah (Malabar) pola segregasinya menunjukkan epistasis duplikat resesif (9 sedang : 7 genjah). Persilangan umur panen sedang (Dieng) dengan umur panen genjah (Grobogan) pola segregasinya menunjukkan bahwa umur panen sedang dikendalikan oleh gen dominan sempurna (3 sedang : 1 genjah). Varietas Grobogan dan Malabar memiliki umur panen sama, tetapi di-kendalikan oleh gen yang berlainan. Varietas Grobogan dan Malabar merupakan tetua dan pasangan persilangan yang prospektif untuk perbaikan umur panen varietas kedelai. Umur panen mempunyai hubungan dengan tinggi tanaman, jumlah buku, hasil biji, jumlah biji maupun ukuran biji per tanaman

Knowledge of gene action that controls character is essential, particularly in connection with the effectiveness of the application of selection to obtain a desired character. A genetic analysis of the days to maturity of a soybean plant is valuable in an improvement program, and there has been very little work done in Indonesia on this subject.The purpose of the research was to obtain information on the genetics of days to maturity, identify the parents and prospective crossing combinations for improvement towards early maturity, and ascertain the close correlation between days to maturity and the produced seeds and components of the soybean yield in the F2 population of a soybean plant. The objects of research were five varieties of soybean, namely Nanti (of very late maturity), Dempo (of late maturity), Dieng (of moderate maturity), as well as Grobogan and Malabar (of early maturity). Research was conducted in two stages, the first of which was formation of plant populations consisting of F1 (P1×P2 crossing) and its F1 reciprocal/F1r (P2×P1 crossing), F2 segregated population (selfing of F1), backcross (BC1.1) (F1×P1 crossing) and backcross (BC1.2) (F1×P2 crossing). The first stage of research was carried out from March 2008 to June 2009 in ILETRI of Malang. The second stage was field research, dealing with genetic of inheritance of days to maturity. This stage was begun in July 2009 and completed in June 2010 in Jambegede experiment station in Malang Regency, East Java. Results of the reseach showed that soybean’s days to maturity on Nanti ×Dempo, Nanti×Dieng, Nanti×Grobogan, Dempo×Dieng, Dempo×Grobogan, Dieng×Grobogan, and Grobogan×Malabar were controlled by the cell nuclei with varying gene actions. The mode of inheritance of soybean’s days to maturity depends on the crossed pairs of parents. The crossing of early days to maturity (Malabar) with late days to maturity (Dempo), the segregation pattern shows dominant and recessive epistases (13 early : 3 late). The crossing of moderate days to maturity (Malabar), the segregation pattern showed recessive duplicate epistases (9 moderate : 7 early). The crossing of moderate days to maturity (Dieng) with early days to maturity (Grobogan), the segregation pattern showed that moderate days to maturity is controlled by perfect dominant genes (3 moderate : 1 early). The Grobogan and Malabar varieties have the same days to maturity, but they are controlled by different genes. The Grobogan and Malabar varieties were the parents and crossing pairs that have the chance of improving soybean towards days to maturity. The days to maturity have correlation with plant height, the number of node, seed yield, number of seeds and size of seeds per plant.

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