(Improvement of Hybrid Varieties of Sweet Corn for High Yield and Resistancy Toward Downy Mildew Disease)

Sriani Sujiprihati1, Muhamad Syukur1*, Andi Takdir Makkulawu2, R Neni Iriany2

ABSTRAK

Jagung manis adalah hasil mutasi resesif yang terjadi secara alami dalam gen yang mengontrol konversi gula menjadi pati dalam endosperm biji jagung. Ada tiga gen utama yang mempengaruhi kemanisan jagung, yaitu gen sugary gen (su), gen sugary enhancer (se), dan gen shrunken (sh2). Tujuan penelitian ini adalah memperoleh informasi nilai daya gabung umum galur-galur jagung manis, yang akan dijadikan tetua dalam persilangan dialel; mendapatkan informasi nilai daya gabung umum, daya gabung khusus galur jagung manis, dan nilai heterosis hibrida jagung manis; dan mendapatkan satu atau lebih calon hibrida silang tunggal yang mempunyai potensi hasil tinggi dan tahan penyakit bulai. Penelitian dimulai April 2009 sampai November 2011. Lokasi penelitian adalah Balai Penelitian Tanaman Serealia (Balitsereal), Maros, Sulawesi Selatan. Lima galur murni memiliki hasil cukup tinggi ketika dilakukan silang puncak dengan varietas bersari bebas Manis Madu, yaitu Mr4/SC/BC4-3-1B, Mr14/SC/BC4-6-1B, Mr11/SC/BC4-3-1B, Mr14/SC/BC3-8-1B, dan Mr12/SC/BC4-6-1B. Tingkat serangan penyakit bulai (downy mildew) tergolong tahan dengan kisaran tingkat serangan antara 0 dan 7%. Kombinasi dari lima galur tersebut dievaluasi dialel lengkapnya. Kombinasi persilangan yang menghasilkan produktivitas lebih baik daripada semua varietas pembanding adalah: C × A (Mr11/SC/BC4-2-1B-1 × Mr12/SC/BC4-5-B-1), A × D (Mr12/SC/BC4-5-B-1 × Mr11/SC/BC4-2-1B-1), E × B (Mr12/SC/BC3-3-1B-1 × Mr14/SC/BC4-6-1B-1), B × D (Mr14/SC/BC4-6-1B-1 × Mr11/SC/BC4-2-1B-1). Dua belas calon varietas mempunyai daya hasil yang tidak berbeda dengan varietas pembanding, sehingga dapat dilanjutkan ke uji multilokasi dengan mengeksplorasi keunggulannya untuk dapat dilepas menjadi varietas baru.

Kata kunci: daya gabung, dialel lengkap, jagung manis, Zea mays  var. Saccharata

ABSTRACT

Sweet corn is a result of recessive mutation which occurs naturally in gene that controls the conversion of sugar into starch in corn seed endosperm. There are 3 main genes that affect corn sweetness, namely sugary gene (su), sugary enhancer gene (se), and shrunken gene (sh2). This study aims to obtain a general combining ability value for the sweet corn lines, which will be the parent in diallel crosses; obtain the information of general combining ability, specific combining ability, and heterosis value for sweet corn lines; and obtain one or more promising single cross hybrids that will be potential for high yield and resistance to downy mildew disease. The study was conducted from April 2009 until November 2011 at the Experimental Field Centre for Cereal Plant Study (BALITSEREAL), Maros, South Sulawesi. The results showed that five genotypes had moderately high yield: Mr4/SC/BC4-3-1B, Mr14/SC/BC4-6-1B, Mr11/SC/BC4-3-1B, Mr14/SC/BC3-8-1B, and Mr12/SC/BC4-6-1B. The attack level of downy mildew that was classified as resistant has 0 to 7% rate. The combination of crosses that produce better productivity than all the varieties are: C × A (Mr11/SC/BC4-2-1B-1 × Mr12/SC/BC4-5-B-1), A × D (Mr12/SC/BC4-5-B-1 × Mr11/SC/BC4-2-1B-1), E × B (Mr12/SC/BC3-3-1B -1 × Mr14/SC/BC4-6-1B-1), and B × D (Mr11/SC/BC4-2-1B-1 × Mr14/SC/BC4-6-1B-1 ). Five hybrids can be continued for the preliminary testing of yields. Twelve candidate varieties do not have yield different than the checked varieties, so it can proceed to a multilocation trials to explore the advantages that can be released as new varieties.

Keywords: combining ability, full diallel, sweet corn, Zea mays var. saccharata