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Abstrak :
Genes related to starch synthesis and the metabolism contribute to a variety of physicochemical properties that determine the eating/cooking qualities of rice. Our previous study suggested that a set of molecular markers was able to estimate the eating quality of japonica rice. The present study reports the genetic diversity of 22 japonica rice varieties based on markers corresponding to starch synthesizing genes. The mean of the polymorphic information content (PIC: 0.135) value and the diversity index (0.171) indicated a low genetic diversity in these varieties. The phylogenetic tree clearly demonstrated three main clusters: 1) cluster I contained seven varieties with similar physicochemical properties; 2) cluster II only showed a Japanese variety, Koshihikari, and 3) cluster III included the most Korean varieties (14 varieties). This phylogenetic analysis did not completely represent the physicochemical properties differentiation of the japonica varieties, although it did reveal an initial clue to the close relationship between Korean rice and the Japanese and Chinese varieties. Notably, these markers were also able to identify a premium japonica rice. The molecular markers and information concerning the genetic relationship would be useful in improving the japonica rice along with its starch quality of in breeding program.

Keragaman Genetik Padi Japonica berdasarkan Marka terkait Gen Sintesis Pati. Gen terkait sintesis dan metabolism pati berkontribusi pada berbagai sifat fisiko-kimia yang menentukan mutu rasa dan hasil masak (cooking) beras. Penelitian sebelumnya menunjukkan bahwa satu set marka molekuler mampu memprediksi mutu rasa beras japonica. Pada studi ini dilaporka keragaman genetik 22 varietas padi japonica berdasarkan marka untuk gen-gen pensintesis pati. Rata-rata nilai polymorphic information content (PIC:0,135) dan indeks keragaman (0,171) menunjukkan keragaman genetik yang rendah dalam varietas padi ini. Pohon filogenetik menunjukkan tiga kelompok utama yang dibentuk: 1) klaster I terdiri dari tujuh varietas dengan sifat fisikokimia yang mirip; 2) klaster II hanya terdiri dari verietas premium Jepang, Koshihikari, dan 3) klaster III mengelompokkan sebagian besar varietas Korea (14 varietas). Analisis filogenetik ini belum sepenuhnya menggambarkan diferensiasi varietas japonica berdasarkan sifat fisiko-kimia, namun hasil ini mengungkapkan petunjuk awal korelasi yang erat antara padi Korea dengan varietas Jepang dan Cina. Marka-marka tersebut juga mampu mengidentifikasi beras premium japonica. Marka molekuler dan informasi kekerabatan genetik ini akan berguna dalam membantu mengembangkan padi japonica terkait dengan mutu pati dalam program pemuliaan

Abstrak :
ABSTRAK This study aimed to investigate the prevalence of the pfdhps and pfdhfr polymorphisms in southern Somalia. The genetic polymorphisms of both genes were analyzed by nested PCR-RFLP. A total of 150 samples were collected; of these, 101 were shown to be positive for Plasmodium (96 P. falciparum and 5 P. vivax) by nested PCR, the remaining 49 were PCR negative. Of the 96 Plasmodium falciparum isolates, 88 were successfully amplified for pfdhps and pfdhfr polymorphisms. The mutations occurring in the pyrimethamine resistance gene (pfdhfr) at codons 51, 59 and 108 were 59 (67.0%), 51 (58.0%) and 83 (94.3%) isolates, respectively. Sulfadoxine resistance-associated mutations in the pfdhps gene at codons 437, 540 and 581 were found in 41 (46.6%), 43 (48.9%) and 13 (14.8%) samples, respectively. The analysis of pfdhfr and pfdhps combination revealed that 27 (30.7%) isolates harbor the quintuple mutations (I51 R59 N108 - G437 E540 A581 and I51 R59 N108 - G437K540G581). The prevalence of single mutation, triple mutations, quadruple mutations and double mutations haplotypes were 19.3%, 18.2%, 15.9% and 12.5%, respectively. Additionally, sextuple mutations were observed at 2 isolates (2.3%). This study shows that the pfdhfr/pfdhps mutant alleles have moderately declined compared to a previous study, but still remain high.