Arif Nirsatmanto

Realized genetic gain observed in second-generation seedling seed orchards of Acacia mangium in South Kalimantan, Indonesia

Realized genetic gains brought by the first-generation tree improvement of Acacia mangium were evaluated by analyzing the 1-year growth performance of growth (height, dbh) and form (stem straightness, multi-stem) traits using data collected from three second-generation orchards: groups B, C, and D. Each orchard was composed of improved families derived from open-pollinated seed of plus trees selected from the first-generation seed orchards and newly added unimproved families collected from the same geographic region. The number of improved families and that of the unimproved in each orchard were 31 and 23 for group B, 28 and 39 for group C, and 24 and 30 for group D. Gains were calculated as percentage increase of improved families over unimproved ones. Improved families performed better than unimproved ones in 11 out of 12 comparison cases: four traits each in the three orchards. Averages of the realized genetic gain across the three seedling seed orchards were 3.1%, 5.2%, 4.3%, and 0.5% for height, dbh, stem straightness, and multi-stem, respectively. Except for multi-stem, the performances of improved families were significantly better than those of unimproved families in all the three orchards for dbh and in two out of three orchards for height and stem straightness.

A projected increase in stand volume of introduced provenances of Acacia mangium in seedling seed orchards in South Sumatra, Indonesia

Abstract Increases in stand volume with some currently introduced provenances of Acacia mangium: Papua New Guinea (PNG) and Far North Queensland (FNQ), were projected based on their superiorities in 3-year height growth in seedling seed orchards using the growth model developed for unthinned plantation for pulp and paper production in South Sumatra, Indonesia. The height growth of these provenances was better than that of the local selections from Subanjeriji by 10%–15% at 3 years old and these percentage superiorities would be expected to remain at around 9%–14% until the 8-year rotation. This amount of increase would result in a 7%–10% increase in basal area and hence it would produce a 17%–26% increase in stand volume at rotation age when compared with the Subanjeriji seed source that was being widely used for the plantation establishment of A. mangium in Indonesia.

Trend of Within-Plot Selection Practiced in Two Seedling Seed Orchards of Acacia mangium in Indonesia

A trend of within-plot selection was examined by applying a retrospective selection index to the results of the selection in two seedling seed orchards ofA. mangium at South Kalimantan in Indonesia. The orchards were established in randomized complete block design with ten replications of four tree row plots. Within-plot selections were conducted twice with around 50% of selection intensity in those orchards: at 22 months and at 51 months after planting, then the results were analyzed with the data on volume, stem form and bole length measured before each selection. Bole length was found to be the highest priority trait throughout the two stages of selection in both orchards. Growth expressed by volume was also an important criterion at the first within-plot selection, while the priority was not obvious at the second selection. Expected gains by within-plot selection were generally small, although predicted gains were positive on all of the three traits at each stage of selection.

SELECTION AND GENETIC GAIN IN THIRD-GENERATION SEEDLING SEED ORCHARD OF Acacia mangium

One of the purposes of seedling seed orchard (SSO) establishment is to produce genetically improved seeds. The amount of genetic gain in the SSO is determined from a series of selection involving within and between family selection in which the gain is generally achieved from the accumulated increases of gain in successive advanced generation breeding cycles. In present study, the amount of genetic gain was predicted in third-generation SSO of Acacia mangium after first within-plot selection using a retrospective selection indexs method. The SSO was established in Wonogiri, Central Java which was laid out in a randomized complete block design, 65 families, six replications, four trees-line plot and spacing of 2 m x 4 m. Actual within-plot selection was subjectively practiced in 40 months after planting. The observed traits for genetic gain prediction was height, diameter at breast height (dbh), and stem straightness using data collected at 24 months after planting. For calculating genetic gain based on multiple trait selection index, coefficient weight for each trait was then derived from the selection differential. The results of study showed that the first within plot selection was practiced mostly for imposing dbh rather than height or stem straightness with the relative gain was 6% for dbh, and 3% for both height and stem straightness. Using the derived coefficient weight, the expected genetic gain by family selection was found to be slightly lower than those predicted by within-plot selection at 3% for dbh, and 2% for both height and stem straightness.

Provenance variation in growth and wood properties of A. mangium and A. auriculiformis in Central Java, Indonesia: selecting potential hybrid parents for good performance

Wood variations among regional and local provenances of 11-year old Acacia mangium and Acacia auriculiformis in Central Java, lndonesia were investigated to obtain the basis data for selecting for superior trees. The regional provenances of Am and Aa were from Papua New Guinea (PNG) and Queensland-Australia (QLD), respectively. Wood cores were extracted at the breast height of each candidate plus trees, and used for measuring the wood propenies. First, a quick and effective method for evaluation of fiber length in an individual tree was investigated. The means at two different positions (Ft) were statistically related to the area weighted fiber length. Ft could be used as the value for the individual tree. Second, provenance variation in wood properties was evaluated by analysis of variance. Among Am provenances, both fiber length and lignin content dilfered signhicantly between PNG and QLD at the 10/o level. Fiber length of PNG (1.09mm) was longer than that of QLD (1.06 mm), and lignin contents of PNG (29.90/o) was lower than that of QLD (30.60/o). All provenances were classhied into three groups (good, medium, and poor petformance) according to the mean values for fiber length, air-dried density, and lignin content. Aa provenances could not be classhied into the good group. These results suggested some Am provenances might provide superior trees with-good performance.