The Cyanogenic Potential of Roots and Leaves of Ninety Nine Cassava Cultivars

Studies on cyanogenic potential (CP) of roots and leaves of Indonesian cassava germplasm are still inadequate in relation to food toxicity and on human health. The CP of leaves of 99 cassava cultivars was analyzed using picrate paper kits. Effort to reduce CP of cassava leaves by boiling them was also conducted. The results showed that roots and leaves had low and moderate level of CP. There was a significant correlation between the CP of leaves (Y) and roots (X) of 45 cassava cultivars with regression equation Y = 36.214 + 1.3085 X (r = 0.5228). The CP content was high in the young leaves (241 ppm) and low in the older ones (99 ppm). The proximal portion of the roots had the highest CP content (300 ppm), and that in the distal end was the lowest (56 ppm). The root part close to cortex had highest CP content (550 ppm), whereas the central part was the lowest (35 ppm). Boiling cassava leaves for 20 minutes significantly reduced the CP up to 75%, indicating that for safety, cassava should be completely processed or cooked. This study implied that CP content should be considered in cassava breeding programs. Forty two of 99 cassava cultivars have CP below 50 ppm which is safe for consumption

Evaluasi Lapang Dan Identifikasi Molekuler Plasma Nutfah Padi Terhadap Keracunan Fe

Fe toxicity is one of the abiotic constraints thatcan significantly decrease rice production, especially inmarginal wetlands. The use of tolerant varieties can reducethe cost of soil processing and fertilizing. Many accessions ofrice germplasm have potential alleles that can be utilized tocreate new varieties tolerant to Fe toxicity. The objectives ofthis research were to evaluate the Fe toxicity tolerance ofrice germplasm and to analyze the genotype diversity usingSNP markers for OsIRT, Fe toxicity tolerant gene(s). Fetoxicity tolerant rice germplasms were screened in acidmarginal wetlands of Taman Bogo Experimental Station,Indonesian Soil Research Insitute, Lampung Province.Meanwhile, the genotypes performance analysis wasconducted on SNP genotyping analysis using SNP markersfor OsIRT gene(s). Based on phenotypic data of 97accessions, which were clustered into six groups, two ofthem (group 2 and group 5) consisted of the tolerantaccessions at both vegetative and generative stages. Theresults of grouping analysis of genotyping based on SNPmarkers were obtained that there were five genotypegroups: AGT, AAT, GAT, AAC, and GAC. The AGT genotypecluster was dominated by the accessions included in group1. Meanwhile, the GAT genotype cluster consisted of mixedtolerant and untolerant accessions to Fe toxicity. The GACgenotype cluster was dominated by the accessions includedin group 2. The accessions which were included in the besttolerant group, group 5, were separated in differentgenotype cluster. Based on association analysis, among thethree SNP markers, OsIRT1 was the most significant SNPmarker (P value = 0.01) which correlated to Fe toxicitytolerant on vegetative stage. Some of the selectedaccessions that were tolerant to Fe toxicity and had goodagronomic performance on acid soil with high Fe contentwere Ketan Alay, Markuti, Arias Halus, Komas a, Lantiak,and Utri Deli. These local rice accessions have the potentialalleles of OsIRT genes

Uji Ketahanan Galur-galur Harapan Padi Terhadap Penyakit Hawar Daun Bakteri (Xanthomonas Oryzae Pv. Oryzae) Ras III, IV, Dan VIII

Resistance Test of Promising Rice Lines Against Bacterial Leaf Blight (Xanthomonas oryzae pv. oryzae) Race III, IV, and VIII. Siti Yuriyah, Dwinita W. Utami, and Ida Hanarida. Development of new superior rice varieties resistant to bacterial leaf blight (BLB) has been conducted through utilizing of a wide rice germplasm, from crossing between IR64 and Oryza rufipogon. The aim of this study is to get promising rice lines that resistant to BLB race III, IV, and VIII. The experiments were conducted at greenhouse and Laboratory of Molecular Biology, ICABIOGRAD Bogor, using of 13 promising rice lines that have different levels of resistance to inoculum from pure cultures of BLB race III, IV and VIII. Of these 13 rice lines, six lines showed resistance to race III (Bio5-AC-Blas/BLB-03, Bio62-AC-Blas/BLB-03, Bio111-BC-PIR7, Bio129-BC-WBC, Bio148-Mamol, and Bio154-Mamol-Dro), one line showed resistance to race IV (Bio154-Mamol-Dro), and one line showed resistance to race VIII (Bio5-AC-Blas/BLB-03), with severity rate 1.8 to 8.1%. Of these improve lines Bio5-AC-Blas/BLB-3 and Bio 111-BCPir- 7, were released as new rice varieties, namely Inpari HDB and Inpari Blas, respectively

Evaluasi Pertumbuhan dan Produksi Padi Gogo Haploid Ganda Toleran Naungan dalam Sistem Tumpang sari

Three doubled haploid (DH) upland rice lines obtained from anther culture having good agronomic and shade  tolerant traits were planted in an intercropping with maize. Their  monoculture systems were also included.  Those lines were GI-8, IG-19, and IW-56. Jatiluhur was also treated similar as shade tolerant control cultivar. The experiment was arranged in randomized complete block design with three replications. The treatments consisted of eight intercropping systems, four monoculture systems of rice, and two monoculture systems of maize. The result showed that all of tested DH lines were consistently shade tolerant under intercropping condition. The characteristics was represented by  similar growth and grain yield with  Jatiluhur under  intercroping system. The highest grain yield was 2.49 t/ha resulted by GI-8 and IG-19 lines  at the time that Jatiluhur was 2.36 t/ha. The intercropping of DH lines with  maize also showed the Land Equivalent Ratio (LER) =1.33-1.58, while Jatiluhur LER = 1.25-1.28, indicating that agronomically they were more advantageous than those in the monoculture system.   Key words :  Doubled haploid,, intercropping system, shade tolerant line

Keragaan Sifat Tahan Penyakit Blas dan Agronomi Populasi Silang Balik dan Haploid Ganda Turunan IR64 dan Oryza Rufipogon

Perakitan varietas tahan blas sebagai galur harapan, merupakan salah satu prioritas dalam program pemuliaan padi. Dalam rangka mendukung program tersebut, telah dilakukan pembentukan populasi haploid ganda (HG) dan silang Balik (BC) dengan IR64 sebagai tetua berulang dan Oryza rufipogon (No. aksesi IRGC 105491) sebagai tetua donor gen tahan penyakit blas. Penelitian ini bertujuan menganalisis keragaan tingkat ketahanan galur-galur haploid ganda (HG_I, HG_II, dan HG_III) dan galur-galur silang Balik (BC2, BC3, dan BC5) terhadap penyakit blas di rumah kaca dan lapang, sehingga diperoleh kandidat galur harapan. Hasil pengujian beberapa populasi HG dan BC menunjukan bahwa terdapat variasi keragaan yang berbeda-beda. Variasi paling kecil terdapat pada populasi HG_III. Hasil yang sama juga diperoleh pada populasi silang Balik (BC2-BC5). Variasi paling kecil terdapat pada populasi BC5. Bila dibandingkan antar populasi HG dan BC, tingkat variasi pada populasi HG_III lebih kecil dibandingkan dengan tingkat variasi pada populasi BC5. Hal ini menunjukkan bahwa tingkat homosigositas paling tinggi terdapat pada populasi HG_III. Berdasarkan evaluasi penampilan agronomis beberapa galur HG_III terpilih, diperoleh tiga galur kandidat galur harapan Bio1, Bio2, dan Bio8