Abstrak. Getah kuning pada daging buah manggis merupakan masalah utama dalam ekspor manggis. Getah kuning sebenarnya adalah getah yang dihasilkan secara alami pada setiap organ manggis, kecuali pada akar. Getah kuning menjadi persoalan manakala getah ini keluar dari salurannya yang pecah dan mengotori aril (daging buah) atau kulit buah manggis. Saluran getah kuning yang pecah berkaitan dengan pecahnya dinding sel epitel penyusun saluran getah kuning diduga kuat dipengaruhi oleh ketersediaan hara, terutama
Ca dan B, dan keseimbangan antar hara di dalam tanah. Penelitian ini bertujuan untuk mengetahui secara komprehensif peranan unsur hara dalam tanah dan kulit manggis dalam mengendalikan cemaran getah kuning pada buah manggis. Hasil penelitian menunjukan bahwa ketersediaan Ca dan B di tanah dan akumulasi kedua hara tersebut di jaringan endokarp berperan langsung menurunkan cemaran getah kuning, sedangkan hara Mn berperan sebaliknya. Keterkaitan ketersediaan hara di tanah dan akumulasinya di jaringan endokarp mendukung bukti bahwa tiga jenis hara, yaitu Ca, B, dan Mn adalah kunci utama dalam mengendalikan cemaran getah kuning.

Kata kunci: Kalsium, boron, mangan, sel epitel, endokarp.

Selengkapnya

Anthracnose is one of the most destructive pepper diseases in Indonesia. Colletotrichum acutatum has been identified as a predominant species in pepper fields of Asian countries including Indonesia. The experiment used completely randomized block design with 2 factors and 4 replications. The first factor was 14 genotypes (c-1,2,3,4,5,7,8,9,15,18,19,28,47, and 49, and the second factor was 4 isolates of C. acutatum (PYK 04, BGR 027, MJK01, and PSG 01). Each experimental unit used 10 green pepper fruits. Inoculation methods followed the AVRDC procedure and resistance score followed the modified procedure of Yoon method. Symptoms were evaluated five days after inoculation. Disease incidence was evaluated using Yoon method with slight modifications. The experiments showed that C-15 genotype was more resistant to anthracnose than others; C-8 and C-49 genotypes were recorded as susceptible to anthracnose. Except the three genotypes, all other genotypes were recorded as highly susceptible to anthracnose. Capsaicin content and peroxsidase activities were not correlated with resistance to anthracnose.

Key words: pepper, resistance, anthracnose, Colletotrichum acutatum

Details

Abstract. Information on genetic variability and correlation between quantitative characters with yield are important for support the selection program. The objective of the research was to estimate the genetic variability, heritability, and path analysis on agronomic characters to determine the selection criteria in the chili. This research was conducted at Research Station of Leuwikopo, Darmaga, Bogor from November 2009 until May 2010. This research observed all populations i.e. F5 population: 320 plants, IPB C2 population: 20 plants, and IPB C5 population: 20 plants. The results showed that total fruit weight, thick and fruit diameter, middle fruit diameter, blossom end fruit diameter, fruit weight, and days to flowering have a high broad sense heritability . High coefficient of genetic variability values were obtained ini number of fruits per plant, fruit weight, stem diameter, fruit diameter, and fruit weight. Based on the heritability, genetic variability, correlations analysis and path analysis, characters that can be used as selection criteria in this study is the number of fruit per plant, fruit weight, and fruit diameter.

Key words: genetic variability, heritability, path analysis, selection

Details