Changes in the structure of the homegardens associated with differences in the community and locations were studied in seven gardens each of the Javanese (Moslem) and Karonese (mainly Christian) communities in North Sumatra, and in eight gardens of the Pegaganese (Moslem) community in South Sumatra, Indonesia. The area of the homegardens was slightly larger in South Sumatra than in North Sumatra, and the area of the fields, including lowland and upland fields belonging to the farmers who owned a garden, was larger in South Sumatra. Although some chickens were frequently kept in homegardens irrespective of the community and location, pigs were kept in the homegardens of only the Karonese. A total number of 168 plant species was observed in 22 homegardens and the number of plant species in the respective gardens of the Javanese, Karonese, and Pegaganese communities was in the range of 21-43, 24-47, and 21-42, respectively. Fruit trees seemed to be the most important crops grown in the homegardens of both North and South Sumatra, especially in South Sumatra, in terms of the number of species and plants, followed by ornamental plants, vegetables, and starchy crops. The number of species and plants in both the industrial and miscellaneous groups was considerably smaller in South Sumatra than in North Sumatra. Banana (Musa spp.) was conspicuous in terms of the number and also in terms of number of plants in all the homegardens. Regardless of the locations, no accessory fruit species except for Garcinia mangostana were detected in the homegardens. The planting density (number of plants/m²) of the homegardens of the Javanese, Karonese, and Pegaganese communities was 0.45, 0.31, and 0.24, respectively, indicating that the productivity of the homegardens in Sumatra was low.

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Among 16 tree diseases collected on 15 tree species in Miyako Island, 8 were newly recorded from the Island and 4 were new diseases caused by each new fungus. For the fungus causing black leaf spot of Stephania, a new genus was established in Phyllachorales as Imazekia ryukyuensis. Cercospora ryukyuensis on Callicarpa, Guignardia hernandiae on Hernandia and Phoma sakishimensis on Antidesma were described as the new species, respectively.

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The emergence of the flower-stalk and the flowering behavior were compared in two groups of mature and premature plants of Phalaenopsis that had been exposed to two different temperature conditions at 20°C and 25°C for 25 days and 50 days each under natural daylength in the summer season.
1. Over 90% of the mature plants produced flower-stalks between late July and early August more or less simultaneously. The flower-stalks in the premature plants emerged much later, and they tended to be taller under the lower temperature conditions and the longer treatment.
2. In the mature plants, over 80% of the flowers bloomed, and anthesis occurred between early and mid-October. In the premature plants, the shorter the treatment, the fewer the flowers that bloomed with considerable delay.
3. In both mature and premature plants most flower-stalks arose from the fifth nodes of the stems.
4. The number of flowers on mature plants was slightly increase at 20°C than at 25°C, and increased more conspicuously after the 50-day treatment than the 25-day treatment. The premature plants bore fewer flowers than the mature ones.
5. The flower-stalks in the mature plants stretched more at 25°C than at 20°C and after the 25-day treatment than the 50-day treatment. The flower-stalks in the premature plants tended to stretch at 20°C.

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Field survey on farm operations and seedling establishment in wet-seeding rice culture in the Muda Irrigation Scheme, Malaysia, was carried out in the second cropping season of 1988. Harvesting and land preparation for seeding were almost fully mechanized and the field conditions at seeding time were generally fair except for some small parcels where harrowing was performed only two times. For wet-seeding, tillage performed three times seems to be appropriate. However, in-field drainage was incomplete in some fields due to the undulating topography and slight differences in ground levels among the fields. Low seedling establishment and vacant spots (areas without seedling establishment covering more than 0.5 m²) were observed due to oxygen deficiency associated with incomplete drainage. The rate of seedling establishment was low in the fields under the following conditions: (1) small size, (2) uneven field topography, (3) relatively low ground levels, (4) proximity to irrigation canals and (5) harrowing performed only two times. The total area of the fields, where vacant spots accound for 6.0% or more of the entire area, amounted to about 20% of the combined area for site A, and about 35% site B. These figures in both sites showed that the drainage at seeding time was insufficient, despite the fact that site B was equipped with a tertiary irrigation canal and drainage. The average number of seedlings established at site A was about 160 plants per m² with the average coefficient of variation of 50%. The coefficients of variation, which depended on the average number of seedlings per m², were high in fields where the average number of seedlings established was lower. The average number of seedlings established at site A was satisfactory. However, about 20% of the fields exhibited a low rate of seedling establishment with an average value of less than 100 plants per m² which resulted in a remarkable yield decrease. To promote a high rate of and uniform seedling establishment, in-field and inter-field irrigation and drainage methods and land preparation practices should be improved.

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RT61 line (derived from Oryza rufipogon) and BT line (derived from O, sativa) which are isogenic lines of Taichung 65 indicated similar inheritance of male sterility. In order to determine whether the cytoplasms and fertility restoring genes of these two lines are identical, the following crossing experiments were carried out.
In the cross of the male sterile line/restorer all the F₁ progenies produced fertile pollen in half of the cases while seed fertility was normal regardless of the kind of paternal (or maternal) lines. In the reciprocal crosses of restorer/restorer since all the F₁ plants produced complete fertile pollen and seeds with fertility, there was no difference in the cytoplasms and the fertiliy restoring genes between the two lines.
However, since it was difficult to determine whether the restoring genes were present at the same locus or were closely linked, three-way croses were conducted.
First, F₁s of the male sterile line/restorer were crossed with Taichung 65. In the offsprings there were plants with complete sterile pollen and sterile seeds and plants with fertile pollen in half of the cases and fertile seeds in a ratio of 1 to 1. It was therefore confirmed that the fertility resoring genes were transmitted normally in other cytoplasms.
Thereafter the F₁s of restorer/restorer were pollinated with Taichung 65. Assuming that the fertility restoring genes of these lines were linked and present at a different locus, segregation of male sterile plants would be expected. However, the results indicated that all the F₁ progenies formed normal pollen and seeds. Therefore, the fertility restoring genes of these lines were considered to display the same function for fertility and to be at the same locus.
The above results sugested that the male sterile cytoplasms of the RT line and BT line belonged to the same type for fertility restoration, and the nuclear fertility restoring genes were present at the same locus with the same function.

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There was a large difference in starch productivity between the planted high-yielding varieties of sago palm (local name “sak sak tru”) and the wild varieties (“wel sak sak”) . The inhabitants in this area have identified 9 superior varieties and 4 wild varieties based mainly in morphological differences, including 1) thorns-presence or lack, their length and patterns of arrangement 2) color or color band of petiole, leaf sheath, rachis and leaflet, 3) extent of leaf bending 4) trunk length and circumference. It was observed that the occurrence and length of thorns showed continuous variations among the varieties, as a result Metroxylon sagus ROTTB. and Metroxylon rumphii MART. were considered to be the same species. Density of sago clumps in high-yielding sago forest was about 40m²/clump, a value similar to that recorded in a sago plantation in Batu Pahat, Malaysia.

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Crop combination in mixed cropping in lowland fields (below 300 min altitude) was surveyed at various locations in West Java. Crop combination, stage of plant growth, cropping sequence, etc. in mixed cropping with special reference to temperate vegetables in highland fields were also surveyed at Lembang (about 1, 200 min altitude), near Bandung. These surveys were carried out'in the rainy season.
In the lowland areas, fruit trees, starchy crops, industrial crops and vegetables were cultivated in mixed stands, especially banana among fruit trees and maize among starchy crops were frequently utilized. Combinations usually consisted of crop plants or trees differing in height, i.e. combinations of coconut palm, banana, maize, and peanut. In mixed cropping including vegetables in the highland area, 17 combinations were observed. Among the six kinds of vegetables cultivated in this area, tomato and cowpea were mostly used, followed by Chinese cabbage, cabbage, and welsh onion, but their combinations, stage of growth of each crop, and sorting or planting times varied markedly among the fields. Some combinations of these vegetables and arboraceous plants such as citrus, apple, coffee, etc., were also observed.
On the basis of the results obtained, the relationship between mixed cropping in cultivated land and homegardens was examined in Java Island, and the possibility to develop a new agricultural system in harmony with the ecosystems was discussed.

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Although many seeds and seedlings are found on the ground under the trees of wild varieties, all the planted sago (superior type) stands were propagated through sucker transplanting, instead of seed propagation. There were differences in the growth rate among the 3 newly planted varieties, and the duration from planting to trunking (rossette stage) was assumed to be 4.5-5 years under favorable conditions. Under the semi-cultivated conditions, each sago clump used to have only a few trunks, which indicated that a proper sucker control method should be developed.

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