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Maria-Carmela T. Posa-Macalincag, George L. Hosfield, Kenneth F. Grafton, Mark A. Uebersax, and James D. Kelly

Canning quality of dry bean (Phaseolus vulgaris L.), of which the degree of splitting (SPLT) and overall appearance (APP) of canned beans are major components, is a complex trait that exhibits quantitative inheritance. The objectives of this study were to identify major genes that affect APP and SPLT in kidney bean, and map the location of these loci to the integrated core map of common bean. The analysis was performed using random amplified polymorphic DNA (RAPD) markers and two populations of kidney bean, consisting of 75 and 73 recombinant inbred lines (RILs), respectively. The two populations—`Montcalm' × `California Dark Red Kidney 82' and `Montcalm' × `California Early Light Red Kidney'—were planted in six year-location combinations in Michigan, Minnesota and North Dakota from 1996 to 1999. Correlations between APP and SPLT were high (0.91 to 0.97). Heritability estimates for APP and SPLT ranged from 0.83 to 0.85 in the two populations. Major genes for these traits were identified on two linkage groups. The first QTL, associated with seven RAPD markers, was putatively mapped to the B8 linkage group of the core bean linkage map. Desirable canning quality appeared to be derived from Montcalm at this locus. The second QTL, associated with four markers, appeared to be derived from the California parents. The second linkage group was not assigned to a linkage group in the core map. Population and environment-specificity were observed for the markers identified.

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Eileen Kabelka, Wencai Yang, and David M. Francis

An inbred backcross (IBC) population derived from Lycopersicon hirsutum LA407 and L. esculentum was evaluated in replicated field trials to assess its potential for the improvement of red-fruited tomatoes. Significant phenotypic variation among genotypes was detected for the hue (tint), L (darkness), and chroma (saturation) of color. Significant effects due to environment and genotype × environment interactions also were observed. One superior inbred backcross line from this population, IBL 2349, was used to develop an F2 population and to explore the genetic basis of color. Two independent L. esculentum quantitative trait loci (QTL) associated with improved color were identified based on linkage to markers mapping to chromosome 4 and chromosome 11. Epistatic interactions were identified between the two L. esculentum loci. Unexpected epistatic interactions also were identified between L. esculentum loci and an LA407 introgression on chromosome 7 present within IBL 2349. The two L. esculentum QTL and the epistatic interactions were confirmed in replicated trials with F3 and F4 families. The loci identified in this study and their epistatic interactions may provide additional tools for the improvement of red-fruited tomatoes in breeding programs.

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Soon O. Park, Dermot P. Coyne, Nedim Mutlu, Geunhwa Jung, and James R. Steadman

Common bacterial blight, incited by Xanthomonas campestris pv. phaseoli (Xcp) is a serious disease of common bean (Phaseolus vulgaris L.). Randomly amplified polymorphic DNA (RAPD) markers and flower color (V gene) previously were reported to be associated with six quantitative trait loci (QTL) affecting leaf and pod resistance to Xcp. However, the markers for the QTL were not confirmed in different populations and environments to indicate their merit in breeding. The objective was to determine if the associations of RAPD markers and the V gene with QTL for leaf and pod resistance to Xcp in a recombinant inbred (RI) backcross population from the cross BC2F6 `PC-50' × XAN-159 and for leaf resistance to Xcp in an F2 population from a different cross pinto `Chase' × XAN-159 could be confirmed. One or two genes from XAN-159 controlled leaf and pod resistance to Xcp. Among six QTL previously detected, five in the RI backcross population and three in the F2 population were confirmed to be associated with resistance to Xcp. The V gene and RAPD marker BC437.1050 on linkage group 5 were most consistently associated with leaf and pod resistance to two to five Xcp strains in the RI backcross population and with leaf resistance to two Xcp strains in the F2 population. One to three QTL affecting leaf and pod resistance to Xcp accounted for 22% to 61% of the phenotypic variation. Gene number (one to two) estimations and number of QTL (one to three) detected for leaf and pod resistance to Xcp in the RI backcross population were generally in agreement. The marker BC437.1050 and V gene, along with other resistance genes from other germplasm, could be utilized to pyramid the different genes into a susceptible or partially resistant bean line or cultivar to enhance the level of resistance to Xcp.

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Maria Jose Gonzalo, Marin Talbot Brewer, Claire Anderson, David Sullivan, Simon Gray, and Esther van der Knaap

al., 2006 ). These analyses resulted in the identification of numerous shape quantitative trait loci (QTL) distributed across the tomato genome ( Brewer et al., 2007 ; Gonzalo and van der Knaap, 2008 ). Shape and size diversity can also be analyzed

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Jim C. Cervantes-Flores, G. Craig Yencho, Kenneth V. Pecota, Bryon Sosinski, and Robert O.M. Mwanga

size to detect quantitative trait loci (QTL) has been strongly emphasized by many researchers ( Collard et al., 2005 ; Doerge et al., 1997 ; Ripol et al., 1999 ; Tanksley, 1993 ). In a polyploid crop such as sweetpotato, a large population size is

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Yan Cheng, Qian Wang, Qingyu Ban, Jianfeng Geng, Xiao Wei Zhang, Ying Yi, and Xilin Hou

China, is an important leafy vegetable in eastern Asia. Many traits of agronomic importance are quantitative in nature and have complex genetic basis. The identification of quantitative trait loci (QTL) represents a first step toward dissecting the

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Xiaoxu Yang, Yinshan Guo, Junchi Zhu, Zaozhu Niu, Guangli Shi, Zhendong Liu, Kun Li, and Xiuwu Guo

. Whereas few articles have, to date, been devoted to understanding the roles of FPPS and HDR , their functions in monoterpene biosynthesis should be further investigated. Table 2. A total of 51 quantitative trait loci (QTLs) detected were significantly

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Cecilia E. McGregor, Vickie Waters, Tripti Vashisth, and Hussein Abdel-Haleem

. Joint analysis (averaged over years) detected the colocalized QTL on chromosomes 2 ( Qdmf2 and Qfmi2 ) and 3 ( Qdmf3-1 , Qdff3-1 , and Qfmi3 ). Table 2. Genomic regions associated with quantitative trait loci (QTL) for days to first male flower (DMF

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Ralf Uptmoor, Mildred Osei-Kwarteng, Susanne Gürtler, and Hartmut Stützel

., 2004 ). Dissecting complex traits into the parameters of ecophysiological models could be used for detecting quantitative trait loci (QTL) responsible for the phenotypic variability, while functional genome analysis provides information on the

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Rui Sun, Hui Li, Qiong Zhang, Dongmei Chen, Fengqiu Yang, Yongbo Zhao, Yi Wang, Yuepeng Han, Xinzhong Zhang, and Zhenhai Han

populations set fruit in 2011; no QTLs were identified successfully. Table 4. Quantitative trait loci (QTLs) for fresh-cut browning detected by interval mapping and Kruskal-Wallis in 2010 in the hybrid population of ‘Jonathan’ × ‘Golden Delicious’. Discussion