Abstract. Hanafiah DS, Trikoesoemaningtyas, Yahya S, Wirnas D. 2010. Induced mutations by gamma-ray irradiation to Argomulyo soybean (Glycine max) variety. Nusantara Bioscience 2: 121-125. Induced mutation by gamma-ray irradiation is one way to increase genetic variability of plants. This research used gamma-ray irradiation on low doses (micro mutation). The aim of this research was to know the response of doses level by micro mutation on gamma-ray irridation to the growing and development of Argomulyo variety of soybean [Glycine max (L) Merr]. The seeds were irradiated by gamma-ray micro mutation doses, namely 0 gray, 50 gray, 100 gray, 150 gray, and 200 gray. Variations that were obtained of each character at generation M1 and M2 influences plants growth and development either through qualitative and quantitative that finally will influence plant’s production. The average highest genetic variation at M2 generation of soybean was on 200 Gray doses. Results of the research indicated that gamma-ray irradiation on 200 Gray doses effectively caused by plant variation genetic.

Heat stress is a major environmental factor limiting wheat productivity in tropical regions such as Indonesia. The objective of this study was to investigate the adaptability of introduced wheat genotypes in tropical agro-ecosystems. Sixteen spring wheat genotypes were grown at two different altitudes i.e. low altitude (176 m asl) with an average temperature of 29.8 o C located at Leuwikopo Field Experimental Station, Bogor Agricultural University, Darmaga Bogor and high altitude (1100 m asl) with an average temperature of 20.6 o C at Cipanas Field Experimental Station (Ornamental Crop Research Station), Cianjur, West Java, Indonesia from July to November 2012. Plant height, number of tillers, flag leaf area, leaf angle, days to flowering, spike number per plant, empty spikelet number, grain weight per plant and 100 grain weight were observed following the standard methods. Heat susceptibility index was calculated based on grain weight per plant. The results showed that cultivation at a low altitude, hotter environment remarkably affected wheat growth and yield, as reflected in overall reduction of plant height, reduced number of tillers and leaf area, and ultimately reduced yield and yield components for most genotypes compared to the same measures taken at high altitude in lower temperatures. Plant growth before heading was similar in both locations, but the days to flowering was longer in high altitude than that in low altitude. High temperature stress in low altitude reduced the spike number/plant, grain weight/plant, 100 grain weight and increase number of empty spikelet/spike. Based on our results for heat susceptibility index, six genotypes, namely Sbr, Ymh, Astreb/Cbrd, Astreb/Ningma, H-20 and Nias, were characterized as heat tolerant genotypes.

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The genetic analysis and selection of transgressive segregants on agronomic characters are required in a sorghumbreeding program for obtaining high proportion homozygosity rapidly in the early generations. This study aimed to obtainthe information on the performance of agronomic characters, estimate genes’ action, broad-sense heritability, coefficient ofgenetic variability, and select transgressive segregant on F2 population of sorghum based on grain yield. The research wasconducted from July 2014 until October 2014 in Dramaga, Bogor. About 300 and 150 individuals F2 populations of B69 ×Numbu and B69 × Kawali, respectively, were used as genetic materials. The results showed that plant height and paniclelength of B69 × Numbu and B69 × Kawali populations were controlled by many genes with additive gene action. The grainyield and grain yield per panicle were controlled by many genes with additive gene action and complementary epistasis,had high heritability, and large coefficients of genetic variability. The transgressive segregant selection had selected 14individuals of B69 × Numbu and 134 individuals of B69 × Kawali populations based on grain yield per panicle.

ABSTRACT<br /><br />The imbalanced supply-demand of soybean is the main reason of soybean import in Indonesia. One of the efforts to increase of soybean production was expanding the planting area to acid soil with a low pH, high content of Aluminum, and low nutrient availability, through giving ameliorant, such as liming organic materials, and mineral fertilization.This study was aimed to obtain the best combination of fertilizer and amelioran for soybean production in acid soil. The study was conducted in experimental station of Tenjo, Bogor from November 2015 to March 2016. The experiment used a randomized complete block design with two factors. The first factor was combinations of fertilizer and amelioran, i.e., P0 (without fertilization); P1 {25 kg urea + 75 kg SP-36 + 50 kg KCl + dolomite ¼ x Aldd (805 kg) ha-1}; P2 {25 kg urea + 75 kg SP-36 + 50 kg KCl + dolomite ¼ x Aldd (805 kg) + 1,250 kg of manure ha-1}; P3 {50 kg urea + 75 kg SP-36 + 50 kg KCl + dolomite ¼ x Aldd (805 kg) + 2,500 kg of manure ha-1}; P4 {75 kg urea + 150 kg SP-36 + 100 kg KCl + dolomite ¼ x Aldd (805 kg) + 2,500 kg of manure ha-1}; P5 {75 kg urea + 150 kg SP-36 + 100 kg KCl + dolomite ½ x Aldd (1,610 kg) ha-1}; P6 {75 kg urea + 150 kg SP-36 + 100 kg KCl + dolomites 1 x Aldd (3,220 kg) ha-1}. The second factor was soybean varieties of Tanggamus and Anjasmoro. The results showed that application of 75 kg urea + 150 kg SP-36 + 100 kg KCl + dolomite ½ x Aldd (1,610 kg) produced the highest productivity (2.91 ton ha-1), but it was not different from reducing the dose of dolomite into ¼ x Aldd (805 kg) with the addition of 2,500  kg of manure.<br /><br />Keywords: Al saturation, chemical properties of soil, nutrient uptake, produktivity, soil amelioran

Genotype × environment interaction (G×E) of harvest period should be involved to assess the suitability of mungbean (Vigna radiata L. Wilczek) for monoculture or intercropping cultivations. This research was aimed to study the effect of G×E interactions on phenology and synchronous maturity, the change of genetic parameter estimates, and the stability of harvest period in mungbean. The study was conducted in Bogor, Indonesia, from December 2017 to October 2018 in four environments: wet season, monoculture (WS.M) and intercropping (WS.I); dry season, monoculture (DS.M) and intercropping (DS.I). Ten mungbean genotypes were evaluated in monoculture and intercropping with sorghum [Sorghum bicolor (L.) Moench] cultivar Numbu using a randomized complete block design with three replications. The phenological traits, namely days to flowering, days to the first harvest, days to 90% harvest, plant height, number of productive branches, seed weight per plant (SWP), and the synchronous maturity traits, namely harvest period, degree indetermination of plant height (DDh1), degree of indetermination of harvest period (DDd2), were observed. The results showed that the G×E interaction effect was highly significant (p < .01) for all phenological and synchronous maturity traits except DDd2. Phenotypic expression of all traits, except SWP and DDh1, were largely controlled by the genetic factor (h 2 bs > 59.83%). Kefa, Kawur, VR480B, Lom2, MLB, Vima 2, VR10, VR60 were stable (b i = 1), VR05 was sensitive (b i = 1.70), and No.129 was insensitive (b i = 0.66) and suitable for monoculture in the dry season. The GGE biplot showed Kefa as a stable genotype with the shortest harvest period. Mungbean selection for synchronous maturity can use harvest period trait in monoculture at dry season.

The efectiveness of selection depends on the gene action cotrolling the character.  The presence of epistatic gene action will delay the genetic gain in self pollinated crops like soybean. The objective of this research was to obtain information on genetic control of soybean tolerance to aluminum toxicity on nutrient culture. This research was conducted at green house of  the University Farm IPB Cikabayan, Bogor, from April to June 2013. This research used 120 seedlings of F2 population  generated from  crossing between Argomulyo (Al-sensitive) with Tanggamus (Al-tolerant). Seedlings were grown in nutrient culture for 14 days with Al concentration of 1.5 mM and pH 4.0, to observe the vegetative growth under aluminum stress condition. The result showed that mean of roots length, shoot length, shoot to root ratio, wet and dry weight of root and shoot exceeded  both parents mean value with moderate to high heritability. All observed characters had continue distribution pattern, and controlled by many genes. Duplicate epistasis additive gene action controlled only root length while other characters were controlled by complementary epistasis gene action.<br />Keywords: gene action, heritability, nutrient culture, selection, tocixity

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