Genotypic and phenotypic correlations among coffee leaf rust symptoms of Arabica coffee genotypes in North Sumatra. Indonesia

Coffee leaf rust (CLR) is a pandemic and a serious threat for coffee sustainability in many coffee producing countries. To overcome this CLR, the world’s consensus is to use of resistant cultivars which can be created through coffee breeding program. This research aimed to study genotypic and phenotypic correlations between CLR symptoms of seven arabica coffee (Coffea arabica L.) genotypes that were selected from different districts of North Sumatra Province, Indonesia. This experimental research using a randomized complete block design with three replications was conducted at the experimental garden of the Faculty of Agriculture, Universitas HKBP Nommensen in Medan. The result of this study indicate that leaf rust severity (LRS) had a genotypic component variance of 86.8% which indicated that LRS was controlled more dominantly by plant genetics than other unknown factors. Severity indicated by LRS showed no genotypic and phenotypic correlation with dispersal indicated by branch rust incidence (BRI) and leaf rust incidence (LRI). BRI genotypically correlated with LRI. The results of this study could contribute to resistance coffee breeding for CLR.

The Effect of Coffee Pulp Composition with Consortia Variation of Indigenic Bacteria on Plant Growth of Coffee Breeding

This study aimed to determine formula and dosage of coffee pulpcompost that is appropriate to the growth of coffee in the nursery phase. The research treatment was a dose of coffee pulp compost with variations of bacterial consortia, using three treatments and one control including, 1) 150 grams of coffee pulp with variations of KA bacteria consortia, 2) 150 grams of coffee pulp with a variety of KB bacterial consortia, 3) 150 grams of coffee pulpwith a variety of consortia of KC bacteria in each treatment there were six replications. The results of the study were found to have an effect on the growth of coffee seedling height and did not significantly influence the growth of the number of leaves of coffee seedlings. This study gives an indication of formula C with 15 indigen bacterial isolates producing the best compost at dose of 150 grams for robusta coffee nursery.

Analysis of Genome Size of Sixteen Coffea arabica Cultivars Using Flow Cytometry

Coffee is an important crop worldwide, grown on about 10 million hectares in tropical regions including Latin America, Africa, and Asia. The genus Coffea includes more than 100 species; most are diploid, except for C. arabica, which is allotetraploid and autogamous. The genetic diversity of commercial coffee is low, likely due to it being self-pollinating, in addition, the widespread propagation of few selected cultivars, such as Caturra, Bourbon, and Typica. One approach is the analysis of genome size in these cultivars as a proxy to study its genetic variability. In the present work, genome size of 16 cultivars was assessed through high-resolution flow cytometry (FCM). Nuclear DNA was analyzed using a modified procedure that uses propidium iodide (PI) and 4′,6′-diamino-2-phenylindole dihydrochloride hydrate (DAPI) staining. The C. arabica cultivars investigated possessed a nuclear DNA content ranging from 2.56 ± 0.016 pg for Typica, to 3.16 ± 0.033 pg for ICATU, which had the largest genome size. All cultivars measured using both fluorochromes had greater estimates with DAPI than PI. The proportion of the genome composed of guanosine and cytosine (GC%) among the cultivars evaluated in this study ranged from 37.03% to 39.22%. There are few studies of genome size by FCM of distinct important C. arabica cultivars, e.g., hybrids and artificial crosses. Thus, this work could be valuable for coffee breeding programs. The data presented here are intended to expand the genomic understanding of C. arabica and could link nuclear DNA content with evolutionary relationships such as diversification, hybridization and polyploidy.

Impact of Long Dry Season on Bean Characteristics of Robusta Coffee (Coffea canephora)

Bean characteristics in Robusta coffee (Coffea canephora) should be taken into considerations in coffee breeding. Beside genetic factor, environment has been known as an important factor in the formation and change of composition of bean characteristics. This research aimed to find out the effect of long dry season on changes of bean characteristics. The population observed consisted of 277 genotypes originated from reciprocal crossings of three parental namely BP 409, BP 961 and Q 121. Observation was conducted in Kaliwining Experimental Garden of ICCRI in Jember, East Java during two years with different drought intensity i.e. 2005—2006 and 2006—2007 production years. The result showed that long dry season decreased the range value of population of normal beans, pea beans and triage beans, and followed by decreasing in the mean value except for normal beans. Long dry season also influence the change of value range of empty bean to higher proportion, and followed by increasing in the mean value. Distribution pattern of normal beans tend in to remain at high proportion, in contrast to those of pea and triage beans. In other side, long dry season tended to change distribution pattern of empty beans to at high proportion. Correlation analysis among beans characteristics showed that normal beans had negative correlations with pea beans and empty beans. Pea beans had a positive correlation with empty beans. Long dry season decreased proportion of pea bean and triage bean, in contrast to those of empty beans. Increasing proportion of empty bean was caused by failure of growth to normal bean under stress condition. Key words : Coffee canephora, bean characteristics, long dry season, variation, correlation, composition.

175 GENETIC TRANSFORMATION OF COFFEE (COFFEA ARABICA L.) BY AGROBACTERIUM SPP.

Efficient genetic transformation could enhance coffee breeding, which is limited by its long generation time and narrow genetic base. Three explant types of three coffee cultivars were inoculated with 14 strains of Agrobacterium spp. Callus and hairy roots were produced with 13 of the 14 strains tested. With A. tumefaciens, nopaline strains were more effective than octopine strains. Cucumopine and mannopine strains of A. rhizogenes were both effective in inducing hairy roots and callus. PCR amplification of a 0.72 Kb fragment of T-DNA encoding a portion of the ipt gene was achieved with DNA from A. tumefaciens strain A208 and with putatively transformed tissue inoculated with A208. No amplification was observed with virB in putatively transformed tissue which indicates it was not contaminated with Agrobacterium. We conclude that coffee can be genetically transformed by some Agrobacterium strains.