Produksi dan Kualitas Jagung Pulut Ungu dengan Kombinasi Dosis Pupuk Nitrogen dan Pupuk Hayati PGPR

Abstract

Jagung pulut ungu memiliki nilai fungsional yang tinggi karena kandungan amilopektin dan antosianin, tetapi produktivitasnya masih belum tinggi. Upaya peningkatan produksi dan kualitas diharapkan dapat dilakukan melalui perbaikan pemupukan dengan pengaturan dosis pupuk nitrogen dan aplikasi pupuk hayati PGPR. Penelitian ini bertujuan memperoleh dosis optimum pupuk nitrogen, pengaruh pupuk hayati PGPR, serta interaksinya terhadap produksi dan kualitas jagung pulut ungu. Penelitian dilaksanakan di Kebun Sawah Baru IPB menggunakan Rancangan Kelompok Lengkap Teracak (RKLT) faktorial dengan dua faktor, yaitu dosis nitrogen (0, 69, 138, dan 207 kg N ha?¹) dan PGPR (0 dan 25 g kg?¹ benih). Pemberian nitrogen berpengaruh nyata terhadap pertumbuhan vegetatif, komponen hasil, dan kualitas jagung pulut ungu. Dosis optimum pupuk nitrogen belum dapat ditentukan berdasarkan penelitian ini, tetapi produktivitas tertinggi diperoleh pada dosis 69 kg N ha?¹ sebesar 3,30 ton ha?¹ dan tidak berbeda nyata dengan dosis 138 maupun 207 kg N ha?¹. Peningkatan dosis nitrogen cenderung menurunkan kelunakan biji dengan nilai berkisar 7,91–12,80 mm 202,5 g?¹ 5 s?¹, sedangkan kadar antosianin tidak berbeda nyata yaitu sebesar 49,43–54,10 mg CGE 100 g?¹ DW. Aplikasi PGPR meningkatkan jumlah tanaman panen, bobot tongkol petak bersih, produktivitas, dan kelunakan biji. Interaksi nitrogen dan PGPR berpengaruh nyata terhadap pertumbuhan vegetatif dan kelunakan biji. Pengaruh dosis nitrogen dan PGPR terhadap kadar amilopektin belum dapat disimpulkan secara statistik karena analisis dilakukan tanpa ulangan dengan kisaran kadar amilopektin yang diperoleh berkisar antara 63,39–73,85%.

Purple waxy corn has high functional value due to its amylopectin and anthocyanin contents; however, its productivity remains relatively low. Efforts to improve production and quality are expected to be achieved through proper fertilization management, including the use of nitrogen fertilization and the application of Plant Growth-Promoting Rhizobacteria (PGPR) biofertilizers. This study aimed to determine the optimum nitrogen application rate, the effect of PGPR, and their interaction on the production and quality of purple waxy corn. The research was conducted at the IPB Sawah Baru Experimental Field using a Factorial Randomized Complete Block Design (RCBD) with two factors: nitrogen rates (0, 69, 138, and 207 kg N ha?¹) and PGPR (0 and 25 g kg?¹ seed). Nitrogen application significantly affected the vegetative growth, yield components, and quality of purple waxy corn. The optimum dose of nitrogen fertilizer could not be determined based on this study. Still, the highest productivity was obtained at a rate of 69 kg N ha?¹ (3.30 tons ha?¹), which was not significantly different from the rates of 138 and 207 kg N ha?¹. Increasing nitrogen doses tended to decrease kernel tenderness, with values ranging from 7.91–12.80 mm 202.5 g?¹ 5 s?¹, while anthocyanin content was not significantly different, ranging from 49.43–54.10 mg CGE 100 g?¹ DW. The application of PGPR increased the number of harvested plants, ear weight per plot, productivity, and kernel tenderness. The interaction between nitrogen and PGPR had a significant effect on vegetative growth and kernel tenderness. The effect of nitrogen rates and PGPR on amylopectin content could not be statistically concluded because the analysis was conducted without replication, with the obtained amylopectin content ranging from 63.39%–73.85%.