One effort to increase maize productivity is by using marginal land for maize plantation. The marginal land that can be used is acid soil, but the problem are Al toxicity and low pH. To cope with these problems, cultivars having tolerance to Al toxicity and low pH are needed. Plant material used in this research were two maize varieties (Pioneer and Srikandi). Media selection is used there are 4 doses treatment aluminium (0, 250, 500 and 750 ppm AlCl3). All variables were observed except at the variable width of the leaf in this results showed that the treatment of aluminium (AlCl3) would not influence. Treatment combination Variety Srikandi and 250 ppm AlCl3 produces plant height, leaf length and leaf width is the shortest compared to other treatments. Variety Pioneer and Srikandi are suspected of varieties resistant aluminum and low pH values based on relative root length. ABSTRAKSalah satu upaya untuk meningkatkan produktivitas jagung yaitu dengan menggunakan lahan marginal untuk ditanami jagung. Lahan marginal yang dapat digunakan adalah tanah masam, tetapi masalahnya adalah keracunan aluminium dan pH rendah. Untuk mengatasi masalah tersebut, dubutuhkan kultivar-kultivar yang toleran keracunan aluminium dan pH rendah. Bahan tanaman yang digunakan pada penelitian ini adalah 2 varietas jagung (pioneer dan srikandi). Media seleksi yang digunakan adalah 4 perlakuan dosis aluminium (0, 250, 500 dan 750 ppm AlCl3). Semua peubah yang diamati pada penelitian ini kecuali lebar daun menunjukkan perlakuan aluminium tidak berpengaruh. Perlakuan kombinasi varietas srikandi dan AlCl3 250 ppm menghasilkan tinggi tanaman, panjang daun dan lebar daun paling pendek dibandingkan perlakuan yang lainnya. Varietas Pioneer dan Srikandi diduga sebagai varietas yang tahan terhadap aluminium dan pH rendah berdasarkan panjang akar relatif.Kata kunci: Zea mays L, Keracunan aluminium, pH tanah, seleksi in vitro

High genetic diversity in chili is the basis for a chili breeding program. One of the methods to increase diversity is through crossing. There are several crossing designs in order to produce new varieties, such as diallel crossing. Diallel analysis is a method for studying the inheritance of characteristics from various crossings. The aim of this research was to estimate the genetic parameters, the general combining ability (GCA) and specific combining ability (SCA) of six inbred lines of chili. The research was conducted in November 2008-May 2009 at the Experimental Farm Leuwikopo IPB. Genetic materials used were six inbred lines of chili (IPB C2, IPB C9, IPB C10, IPB C14, IPB C15 and IPB C20) and the F1s of the combination of six inbred lines. The experimental design was Randomized Complete Block Design with a single factor, namely genotype. The number of genotypes were 36 with three replications, so there were 108 units of experiment. The crossing design used was diallel crossing design. The results showed that there were no interaction between genes on the dichotomous height and fruit weight, significant additive effects, the control genes spread unevenly, and relatively high heritability values. Genotype which carried recessive genes the most was IPB C14 and genotype which carried the most dominant genes was IPB C10. IPB C10 showed the highest GCA for dichotomous height and IPB C2 showed the highest GCA on fruit weight. The crossing between IPB C2 x IPB C10 showed the highest SCA for dichotomous height. For fruit weight, crossing of IPB C2x IPB C14 had the highest SCA. Crossing combination of IPB C2 x IPB C14 was the best hybrid.

Breeding rice varieties suitable for low temperature areas is very important to support food self-sufficiency. Identification of polymorphic markers assumed to be associated with low temperature tolerant properties is essential for mark-based selection applications in the context of low temperature tolerant rice variety development. The study was conducted to identify 5 rice genotypes to be used as a low temperature tolerant donor hybrid using 11 SSR markers. PCR product amplification was separated using 3% agarose gel and 8% electrophoresis polyacrylamide gel (PAGE). The level of information of a mark can be determined by calculating the Polymorphic Information Content (PIC). The study was conducted in May - July 2017 at the Laboratory of Molecular Biology, Centre for Research and Development of Biotechnology and Genetic Resources of Agriculture, Bogor. The results showed that 6 SSR markers were polymorphic and 5 markers were monomorphic. CT234 and CT235 markers have the highest PIC value (0.375) compared to 9 other markers. SSR markers and specific gene markers used to identify low temperature tolerant rice show that Ciherang and Sigambiri Putih crossbreeding can be recommended as a crossing parents because it has the most distant genetic (0.431).

Uncertain climate change impacts the difficulty of predicting the intensity of floods that hit rice fields in flood-prone areas, both the duration of the submerged plants and the height of the water surface. In order to evaluate the tolerance level and response of several local rice genotypes to submersion stress in the vegetative phase, 50 rice genotypes were screened (47 North Sumatran local varieties, 3 VUB), using special ponds to simulate flooding or inundation stress. The study used a separate plot design with three replications; the main plot was three immersion models, namely full immersion, partial soaking, and not soaking, and subplots of 50 rice genotypes. The immersion treatment was defined as a different growing environment. The results showed that in the fully submerged treatment, the recovery capacity of local rice plants only ranged from 0-20%. The new, improved varieties tested were Inpari 4 (susceptible), Inpari 3, 10, Ciherang, Inpara 2 (very susceptible), Inpari 30, FR13A (very tolerant). Submersion tolerant genotypes had a slight increase in plant height after being fully submerged. The chlorophyll content in the leaves decreased immediately after the soaking stress period (14 DAP) in all rice genotypes. The local rice genotypes tested were very susceptible to immersion; the new superior variety Inpari 4 was categorized as susceptible, while Inpari 30 and FR13A were very tolerant.

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