Mutu Fisik dan Fisiologis Benih Sorgum (Sorghum bicolor L. Moench) dari Pemupukan dan Tingkat Kemasakan Berbeda

Abstract

Ketersediaan benih sorgum bermutu perlu ditingkatkan untuk pengembangan budidaya tanaman sorgum. Aplikasi pupuk anorganik atau kombinasi pupuk anorganik dan organik dapat berpengaruh terhadap hasil produksi. Bunga pada malai sorgum tidak serempak mekarnya, sehingga diduga benih yang terbentuk tidak seragam masak fisiologinya. Hal ini akan berdampak terhadap mutu benih yang dihasilkan. Penelitian bertujuan menetapkan dosis pemupukan dan waktu panen yang tepat untuk produksi dan mutu benih sorgum yang tinggi. Penelitian dilaksanakan bulan Januari hingga Mei 2024 di Kebun Percobaan Sawah Baru dan Laboratorium Pengujian dan Penyimpanan Mutu Benih IPB. Rancangan percobaan yang digunakan rancangan kelompok lengkap teracak dua faktor yaitu pemupukan dan tingkat kemasakan. Faktor pertama terdiri atas tiga taraf yaitu tanpa pupuk, pupuk anorganik (urea 200 kg ha-1, SP-36 100 kg ha-1, dan KCl 100 kg ha-1), dan pupuk anorganik+organik (urea 200 kg ha-1, SP-36 100 kg ha-1, dan KCl 100 kg ha-1+ pupuk kandang sapi 5 ton ha-1). Faktor kedua terdiri atas tiga tingkat kemasakan, benih dipanen 35 hari setelah antesis malai bagian ujung, tengah, dan pangkal. Kombinasi pupuk organik dan anorganik (pupuk urea 200 kg ha-1, SP-36 100 kg ha-1, dan KCl 100 kg ha-1 + pupuk kandang sapi 5 ton ha-1) memberikan hasil produksi benih sorgum tertinggi. Panen benih 35 hari setelah antesis berdasarkan antesis bunga pada bagian malai ujung dan tengah menghasilkan produksi dan mutu yang tidak berbeda. Mutu benih yang berada pada bagian atas dan tengah malai tidak berbeda. Mutu benih dari malai bagian bawah tidak dipengaruhi oleh waktu panen, tetapi mutunya cenderung lebih rendah.

The availability of high quality sorghum seeds needs to be increased to develop sorghum cultivation Inorganic fertilizers or a combination of inorganic and organic fertilizer application can effect the yield. It is necessary to determine whether applying inorganic fertilizers alone or combining them with organic fertilizer will affect yield. The flowers on the sorghum panicle do not reach anthesis simultaneously, so it is suspected that the seeds formed do not reach physiological maturity uniformly. This research aims to determine the appropriate type of fertilizers and harvest time for high seed yield and seed quality of sorghum. The study was conducted from January to May 2024 at Sawah Baru Experimental Station and Seed Quality Testing and Storage Laboratory of IPB University. The study was arranged in a Randomized Complete Block Design (RCBD) with two factors: fertilization and seed maturity stage. The first factor consists of three levels: no fertilizer, inorganic fertilizer (urea 200 kg ha-1, SP-36 100 kg ha-1, and KCl 100 kg ha-1), and inorganic + organic fertilizers (urea 200 kg ha-1, SP-36 100 kg ha-1, and KCl 100 kg ha-1 + manure 5 tons ha-1). The second factor consists of three levels: seeds were harvested at 35 days after anthesis of the distal, middle, and proximal parts of the panicle. The result showed that organic + inorganic fertilizers (urea 200 kg ha-1, SP-36 100 kg ha-1, and KCl 100 kg ha-1 + manure 5 tons ha-1) produced the highest sorghum seed yield. Harvesting sorghum seeds at different maturity stages (35 days after anthesis of the distal, middle, and proximal parts of the panicle) did not affect seed yield and physical quality. However, it is recommended to harvest sorghum seeds 35 days after anthesis of the distal or middle part of the panicle to obtain seeds with higher vigor. Harvesting seeds 35 days after anthesis based on flower anthesis of the distal and middle parts of the panicle did not affect seed yield and seed viability. The seed quality of upper and middle parts of the panicle is not significantly different. The seed quality of lower parts of the panicle did not affected by the maturity stages, but the seed quality tends to be lower.