Judul: Fenologi Pembungaan dan Penyerbukan Buah Naga Hylocereus undatus, Hylocereus costaricensis dan Selenicereus megalanthus
Abstrak: The objectives of this reseach was to observe flowering phenology of dragon fruit (Hylocereus undatus, Hylocereus costaricensis and Selenicereus megalanthus) and to investigate if pollination types affect fruit quality. This research consisted of two experiments; the first is observation on flowering phenology. The second experiment was arranged in randomized complete block design with type of pollination as the treatment, i.e open pollination of H. undatus (P1), controlled self pollination of H. undatus (P2), controlled cross pollination of H. undatus x H. costaricensis (P3), open pollination of H. costaricensis (P4), controlled self pollination of H. costaricensis (P5), and controlled cross pollination of H. costaricensis x H. undatus (P6). The treatments were repeated 4 times. Development of flower bud until blooming in Hylocereus spp. was about 19-21 days, while in S. megalanthus took 29-31 days. Based on pollen viability and stigma receptive period, the optimal pollination time was between 11.00 pm to 2.00 am for the three species. All types of pollination resulted in 100% fruit set. Fruit weight from self pollination of H. costaricensis was the highest among types of pollination, while total soluble solid from controlled cross pollination of H. undatus x H. costaricensis was the highest. Controlled pollination, both self and cross of H. costaricensis produced bigger fruit than open pollination.
Keyword: receptivity stigma, pollen viability, fruit set, self pollination

Judul: Hama dan penyakit tanaman buah naga (Hylocereus sp.) serta budidayanya di Yogyakarta
Abstrak: Dragon fruit (Hylocereus sp.) has been introduced to Indonesia recently and became a commercial crop cultivated in this country. The plant, which belongs to family of Cactaceae (cactus), is native to Mexico, Central, and South America. There are no many reports about significant losses due to pests and diseases of the plant in Indonesia, or even in other countries. However, it is potential that pests and diseases can become problem in the future as the plant become widely grown in Indonesia. The objective of this research is to gather information about pest and disease occurrences found in dragon fruit and its cultivation in Yogyakarta. The research methods including interview with farmers, observation, and sampling of the pests and diseases at six dragon fruit orchards, field, and laboratory identification of the causal agents, and data processing. The pests found in dragon fruit were mealy bugs (Hemiptera:Pseudococcidae) species Pseudococcus jackbeardsleyi, Ferrisia virgata, and Planococcus sp.; aphids (Hemiptera:Aphididae) species Aphis gossypii., Branchycaudus helichrysi, and Toxoptera odinae; ants (Hymenoptera:Formicidae) species Oecophylla sp., Camponotus sp., Euprenolepis sp., and Polycharis sp.; grasshoppers (Orthoptera:Acrididae) species Valanga sp., Oxya sp., and Atractomorpha sp.; mite (Acarina:Tetranycidae); snail (Acathina fulica); and birds. Chickens are not considered as a pest, however, they can cause severe damage on fruit if they are allowed to present in the orchard. Diseases found in dragon fruit were algae red rust (Cephaleuros sp.), vine orange spot (Fusarium sp.), white vine (Botryosphaeria sp. and Phomopsis sp.), stem blight (Helminthosporium sp.) and anthracnose (Colletotrichum sp.), Dothiorella spot, brownish stem rot, stem yellowing, fruit rot (Colletotrichum sp. and Helminthosporium sp.) fruit orange spot (Alternaria sp.). A black spot disease on stem has not been identified yet. Pests and diseases have not been controlled in particular system, probably because their occurrences have not resulted in a significant loss.
Keyword: 

Judul: Invers Drazin dari Matriks Toeplitz Singular
Abstrak: Matriks Toeplitz adalah matriks yang setiap unsur pada diagonal utama bernilai sama dan setiap unsur pada subdiagonal yang bersesuaian dengan diagonal utama juga bernilai sama. Matriks singular adalah matriks yang tidak bisa ditentukan inversnya. Akan tetapi, dapat diupayakan untuk ditentukan inversnya menggunakan invers matriks yang diperumum. Invers Drazin merupakan salah satu jenis invers matriks yang diperumum. Pada karya ilmiah ini ditentukan invers Drazin dari matriks Toeplitz singular dengan menggunakan metode Leverrier Faddeev. Kemudian, ditentukan invers Drazin dari matriks Toeplitz singular yang direpresentasikan sebagai penjumlahan segitiga bawah dan segitiga atas matriks Toeplitz berdasar pada teorema Gohberg dan Semencul., Toeplitz matrix is a matrix in with element on the main diagonal has the same value and on the subdiagonal corresponding to the main diagonal also has the same value. Singular matrix is a matrix that has no inverse. However, it can be attempted to determine the inverse using a generalized inverse matrix. Inverse Drazin is a type of generalized matrix inverse. This paper discussed the inverse Drazin for a singular Toeplitz matrix using the Leverrier Faddeev method. Then, the Drazin inverse of the singular Toeplitz matrix which is represented as a sum of products of lower and upper triangular Toeplitz matrix based on Gohberg and Semencul theorem.
Keyword: inverse Drazine, singular Toeplitz matrix