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"An F2 rice population developed from a cross between a backcross inbred line (BIO-148) and its recurrent parent (IR64) was used to identify quantitative trait loci (QTL) for awn, panicle exertion and total spikelet number. BIO-148 is a BC2F8 line derived from a cross between IR64 (a high-yielding lowland rice variety) and Gajah Mungkur (an upland tropical japonica rice variety). Two hundred plants were grown in the greenhouse, and their DNAs were isolated for genotyping using SSR markers. Panicle exertion was observed during the grain-filling stage. The awn length of the seed and the total spikelet number per panicle were observed after harvesting. A total of four QTLs were identified using single-marker regression with LOD>3, explaining 8.4-18.1% of phenotypic variation. A QTL for awn was identified on Chromosome 8. A QTL for incomplete panicle exertion was identified on Chromosome 4. Two QTLs for total spikelet number were identified on Chromosome 4, in which the BIO-148 allele contributed to a higher number of spikelets per panicle. The QTLs identified in this study will be useful in the improvement of yield potential for modern lowland indica rice varieties by harnessing the hidden useful alleles from upland tropical japonica rice varieties."

"An F2 rice population developed from a cross between a backcross inbred line (BIO-148) and its recurrent parent(IR64) was used to identify quantitative trait loci (QTL) for awn, panicle exertion and total spikelet number. BIO-148 isa BC2F8 line derived from a cross between IR64 (a high-yielding lowland rice variety) and Gajah Mungkur (an uplandtropical japonica rice variety). Two hundred plants were grown in the greenhouse, and their DNAs were isolated forgenotyping using SSR markers. Panicle exertion was observed during the grain-filling stage. The awn length of the seedand the total spikelet number per panicle were observed after harvesting. A total of four QTLs were identified usingsingle-marker regression with LOD>3, explaining 8.4-18.1% of phenotypic variation. A QTL for awn was identified onChromosome 8. A QTL for incomplete panicle exertion was identified on Chromosome 4. Two QTLs for total spikeletnumber were identified on Chromosome 4, in which the BIO-148 allele contributed to a higher number of spikelets perpanicle. The QTLs identified in this study will be useful in the improvement of yield potential for modern lowlandindica rice varieties by harnessing the hidden useful alleles from upland tropical japonica rice varieties.Identifikasi Lokus Sifat Kuantitatif (Quantitative Trait Loci/QTL) untuk Sifat Panjang Sungut, Eksersi Malaidan Jumlah Spikelet pada Populasi F2 Tanaman Padi yang berasal dari Galur Silang Balik antara Bio-148dengan Tetua Berulangnya, IR64. Populasi F2 dikembangkan melalui persilangan antara galur silang balik inbrida(Bio-148) dan tetua berulangnya (IR64) dan digunakan untuk mengidentifikasi lokus sifat kuantitatif (QTL) untuk sungut(awn), eksersi malai dan jumlah total spikelet per malai. Bio-148 merupakan galur BC2F8 yang berasal dari persilanganantara IR64 (varietas unggul hasil tinggi-dataran rendah) dengan Gajah Mungkur (jenis padi japonica tropis-datarantinggi). Dua ratus individu tanaman ditanam di rumah kaca dan diisolasi DNAnya untuk digenotip menggunakan markaSSR. Eksersi malai diamati pada fase pengisian bulir. Panjang sungut biji dan jumlah total spikelet per malai diamatisetelah panen. Sebanyak 4 QTL berhasil diidentifikasi menggunakan regresi marka tunggal (SMR) dengan LOD>3,yang menjelaskan 8.4-18.1% variasi fenotipik. Sebuah QTL untuk sungut diidentifikasi pada kromosom 8, QTL untukeksersi malai yang tidak sempurna diidentifikasi pada kromosom 4. Dua QTL untuk sungut diidentifikasi padakromosom 4, dimana alel dari Bio-148 berkontribusi terhadap tingginya jumlah spikelet per malai. QTL yangdiidentifikasi dalam studi ini akan berguna bagi peningkatan potensi hasil varietas padi indica dataran rendah denganmemanfaatkan alel-alel berguna yang tersembunyi yang berasal dari varietas padi tropical japonica dataran tinggi."

"Padi mampu menggunakan protein ferritin untuk melindungi diri dari toksisitas besi. Protein ferritin merupakan suatu protein berbentuk sferis yang dapat mereduksi besi sehingga menghilangkan potensi toksisitas besi. Padi yang tahan toksisitas besi telah ditemukan di antaranya padi INPARA2, Mahsuri, Pokkali, dan Siam Saba. Penelitian mengenai analisis sekuen gen ferritin diperlukan untuk membentuk strategi pemuliaan varietas padi yang tahan toksisitas besi. Penelitian ini bertujuan untuk melakukan analisis sekuen gen OsFer1 dan OsFer2 pada padi varietas Ciherang, Cibogo, dan INPARA 8. Sekuen gen ferritin berupa kromatogram yang didapat adalah sekuen gen OsFer1 dan sekuen gen OsFer2 Sekuen OsFer1 ditemukan pada ketiga varietas dan ditemukan sekuen OsFer2 pada padi varietas Ciherang dan Cibogo. Sekuen yang ditemukan berupa sekuen parsial yang terdapat pada ekson1, intron 1 dan ekson 2 dengan sekuen OsFer1 yang sepanjang 530 dan 568 pasang basa. Sekuen OsFer2 ditemukan sepanjang 212 pasang basa. Sekuen OsFer1 dan Sekuen OsFer2 ditemukan memiliki kemiripan sekuen yang tinggi jika dibandingkan dengan sekuen referensi. Sekuen OsFer1 dan OsFer2 ditemukan menunjukkan banyak mismatch yang berbentuk mutasi subtitusi. Sekuen OsFer2 menunjukkan adanya 14 mutasi deep intronic dan 2 mutasi proximal intronic. Sekuen OsFer1 menunjukkan adanya 1 mutasi exonic.

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Rice is capable of utilizing ferritin in response to iron toxicity. Ferritin is a spherical protein that can reduce iron thus neutralizing its toxicity. Several rice varieties have been found to show considerable tolerance to iron toxicity such as INPARA2, Mahsuri, Pokkali, and Siam Saba. Sequence analysis studies focusing on ferritin genes is important for future rice breeding programs. This study is aimed to analyze OsFer1 and OsFer2 gene sequence in Ciherang, Cibogo, and INPARA 8. The sequences obtained in this study are chromatograms showing partial sequences from OsFer1 and OsFer2. The length of OsFer1 sequences are 530 and 568 base pairs and OsFer2 with 212 base pairs. OsFer1 sequences are recovered from the three rice varieties and OsFer2 are found from Ciherang and Cibogo. OsFer1 and OsFer2 showed high similarity when compared to reference sequence. OsFer1 and OsFer2 showed high alignment with exon 1, intron 1 and exon 2. Mismatches were found in both sequences that are base subtitutions. Intronic mutations are found in OsFer2 sequence and exonic mutations are found in OsFer1. "