PERBANDINGAN KEMAJUAN GENETIS SELEKSI MASSA DAN TONGKOL-KE-BARIS PADA POPULASI GENERASI KETIGA PERSARIAN BEBAS JAGUNG HIBRIDA (Zea mays L.)

RIZQI FADILLAH R, Dr. Panjisakti Basunanda, S.P., M.P.

2014 | Skripsi | PEMULIAAN TANAMAN

Di negara berkembang, bahan perbaikan genetik jagung sering kali dibuat melalui ekstraksi populasi turunan kultivar hibrida yang telah dilepas di pasaran, dengan disertai perbaikan dalam populasi. Pada populasi generasi ketiga hasil persarian bebas jagung hibrida, kemajuan genetik melalui seleksi massa ataupun seleksi tongkol-ke-baris (famili saudara tiri) perlu dibandingkan untuk mengetahui metode seleksi yang sesuai. Hal ini dilakukan karena populasi generasi ketiga persarian bebas belum mencapai kesetimbangan pada semua lokusnya, sehingga varians dalam dan varians antar famili belum homogen. Penelitian ini bertujuan untuk membandingkan nilai kemajuan genetik harapan seleksi massa dengan seleksi tongkol-ke-baris pada beberapa karakter ekonomis jagung, dan mendapatkan galur-galur untuk memperbaiki penampilan populasi segregasi hasil persarian bebas keturunan kultivar hibrida. Penelitian dilakukan menggunakan benih jagung dari 24 famili saudara tiri (tongkol) hasil persarian bebas jagung hibrida generasi kedua dengan pola tanam satu tongkol satu baris dan diulang dua kali dengan ulangan berupa blok. Pengamatan meliputi tinggi tanaman, tinggi tongkol, panjang tongkol, diameter tongkol, bobot biji per tanaman dan banyak biji per tanaman. Data yang diperoleh dianalisis dengan analisis varians untuk menduga keterwarisan (heritability) melalui pemilahan nilai harapan rerata kuadrat (expected mean squares). Keterwarisan ini digunakan untuk menghitung nilai kemajuan genetik harapan (R) dari masing-masing metode seleksi dengan tekanan seleksi (proporsi) 5%. Seleksi massa dengan memperhatikan pengaruh blok memberikan nilai R tertinggi untuk tinggi tanaman. Seleksi massa mengabaikan pengaruh blok memberikan nilai R tertinggi untuk kedudukan tongkol dan diameter tongkol. Seleksi tongkol-ke-baris berbasis rerata plot memberikan nilai R tertinggi untuk panjang tongkol sedangkan yang berbasis rerata famili untuk bobot biji per tanaman dan banyak biji per tanaman.

In developing countries, maize genetic improvement materials are often made through extraction of populations derived from hybrid cultivars that have been released in the market, involving intra-population improvement in the population. In the third generation of random mating population from hybrid maize, response selection through mass selection or ear-to-row selection needs to be compared to determine the appropriate method of selection in this population. In the third generation of random mating population, equilibrium has not been reached, resluting in discrepancies of within family and between family variance. The objective of this work is to compare response selection of the mass and ear-to-row selection method in a number of commercial characters of maize and to obtain lines to improve the performance of the selected population. Twenty four half-sib families (ears) obtained from cross pollination of second generation of random mating population are planted with one ear one row pattern in two blocks as replicates. This population was evaluated for six characters: plant height, ear height, ear length, ear diameter, kernels weight per plant and number of kernels per plant. The observation data was analysed using analysis of variance to estimate the heritability by separating the expected mean of squares. The heritability is used to predict the response selection (R) in every method with selection pressure (proportion) of 5%. Mass selection by considering the block effect gave the highest R value for plant height. Mass selection without block effect gave the highest R value for ear height and ear diameter. Ear-to-row selection based on plot mean gave the highest R value for ear length and the family mean based of ear-to-row for grain weight per plant and number of kernels per plant.

Kata Kunci : jagung, kemajuan genetik, seleksi massa, seleksi tongkol-ke-baris