Kemosensitivitas Bawang Putih (Allium sativum L.) terhadap Oryzalin dan Kolkisin serta Evaluasi Sitologi, Anatomi, dan Morfo-Agronomi

Abstract

Garlic (Allium sativum L.) is an important horticultural commodity; however, low national production has caused Indonesia to remain dependent on imports. Local garlic generally has relatively smaller bulbs and cloves than imported garlic. Polyploidization induction using oryzalin and colchicine has the potential to increase variation and improve the traits of local garlic. This study aimed to analyze the chemosensitivity of garlic cloves of the Lumbu Putih, Lumbu Hijau, and Lumbu Kuning varieties to polyploidization induction and to evaluate their cytological, anatomical, and morpho-agronomic traits. Induction was carried out using oryzalin and colchicine at concentrations of 0, 100, and 200 µM. Lumbu Putih and Lumbu Hijau cloves were soaked for 1 day, whereas Lumbu Kuning cloves were soaked for 3, 5, and 7 days. Chemosensitivity was analyzed based on tissue viability and sprouting ability. Ploidy level was analyzed using flowcytometry and chromosome observation. Anatomical variables included stomatal size, stomatal density, and chloroplast number. Morpho-agronomic variables included plant height, stem diameter, leaf chlorophyll index, root weight, whole-plant fresh weight, bulb diameter, bulb weight, and number of cloves. The chemosensitivity response of garlic differed among varieties and mutagen treatments. Lumbu Putih and Lumbu Hijau cloves showed high tissue viability after mutagen soaking, although their growth responses varied among treatments. For Lumbu Kuning, longer soaking duration reduced tissue viability and growth ability, particularly under colchicine treatment. Evaluation of the first generation showed that Lumbu Putih and Lumbu Hijau remained diploid, and mutagen treatment did not significantly affect their anatomical characters. Morpho agronomic characters of Lumbu Putih did not differ significantly after induction, whereas Lumbu Hijau showed increased stem diameter and root weight under 100 µM colchicine. For Lumbu Kuning, mixoploid plants were formed, and the highest proportion was obtained following treatment with 200 µM oryzalin for 3 days. The mixoploid group had the highest anatomical variability and number of chloroplasts in guard cells. The treated diploid group had higher stem diameter, bulb diameter, whole-plant fresh weight, and bulb weight than the control and mixoploid groups. Ploidy level analysis in the second generation showed that all Lumbu Kuning progenies derived from first-generation mixoploid plants were detected as diploid, indicating the occurrence of diplontic selection. The morpho-agronomic characters of second-generation Lumbu Putih and Lumbu Hijau plants derived from polyploidization-induced plants did not differ significantly from their respective controls. The diploid progeny group of Lumbu Kuning showed higher chlorophyll content and stem diameter than the control and the progeny group derived from mixoploid plants.

Bawang putih (Allium sativum L.) merupakan komoditas hortikultura penting, tetapi produksi nasional yang rendah menyebabkan Indonesia masih bergantung pada impor. Bawang putih lokal umumnya memiliki ukuran umbi dan siung relatif kecil dibandingkan bawang putih impor. Induksi poliploidisasi menggunakan oryzalin dan kolkisin berpotensi meningkatkan keragaman dan memperbaiki karakter bawang putih lokal. Penelitian ini bertujuan menganalisis kemosensitivitas siung bawang putih varietas Lumbu Putih, Lumbu Hijau, dan Lumbu Kuning terhadap induksi poliploidisasi serta mengevaluasi karakter sitologi, anatomi, dan morfo-agronomi. Induksi dilakukan menggunakan oryzalin dan kolkisin pada konsentrasi 0, 100, dan 200 µM. Siung Lumbu Putih dan Lumbu Hijau direndam selama 1 hari, sedangkan Lumbu Kuning direndam selama 3, 5, dan 7 hari. Kemosensitivitas dianalisis berdasarkan viabilitas jaringan dan daya tumbuh. Level ploidi dianalisis menggunakan flowcytometry dan pengamatan kromosom. Peubah anatomi meliputi ukuran stomata, densitas stomata, dan jumlah kloroplas. Peubah morfo-agronomi meliputi tinggi tanaman, diameter batang, klorofil, bobot akar, bobot basah tanaman utuh, diameter umbi, bobot umbi, dan jumlah siung. Respons kemosensitivitas bawang putih berbeda antarvarietas dan antarperlakuan mutagen. Siung Lumbu Putih dan Lumbu Hijau memiliki viabilitas jaringan yang tinggi pasca-perendaman dalam mutagen, meskipun daya tumbuhnya bervariasi antarperlakuan. Pada Lumbu Kuning, peningkatan durasi perendaman menurunkan viabilitas dan daya tumbuh, terutama pada kolkisin. Evaluasi generasi pertama menunjukkan bahwa Lumbu Putih dan Lumbu Hijau tetap terdeteksi sebagai diploid, serta perlakuan mutagen tidak menyebabkan perubahan nyata pada karakter anatomi. Karakter morfo-agronomi Lumbu Putih tidak menunjukkan perubahan nyata akibat perlakuan induksi, sedangkan Lumbu Hijau menunjukkan peningkatan diameter batang dan bobot akar pada perlakuan kolkisin 100 µM. Lumbu Kuning menunjukkan respons sitologi berupa terbentuknya tanaman miksoploid, dengan proporsi tertinggi dari perlakuan oryzalin 200 µM selama 3 hari. Kelompok miksoploid Lumbu Kuning memiliki keragaman anatomi tertinggi dan jumlah kloroplas sel penjaga tertinggi. Kelompok diploid Lumbu Kuning hasil perlakuan induksi memiliki diameter batang, diameter umbi, bobot basah tanaman utuh, dan bobot umbi lebih tinggi dibandingkan kontrol dan kelompok miksoploid. Analisis konfirmasi level ploidi generasi kedua menunjukkan bahwa seluruh turunan Lumbu Kuning asal tanaman generasi pertama miksoploid terdeteksi sebagai diploid, yang mengindikasikan terjadinya diplontic selection. Karakter morfo-agronomi Lumbu Putih dan Lumbu Hijau generasi kedua asal tanaman hasil induksi poliploidisasi tidak menunjukkan perubahan nyata dibandingkan kontrol. Kelompok turunan diploid Lumbu Kuning memiliki nilai klorofil dan diameter batang lebih tinggi dibandingkan kontrol dan kelompok turunan miksoploid.