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Mobashwer Alam, Craig Hardner, Catherine Nock, Katie O’Connor, and Bruce Topp

The Hawaiian cultivars Keaau (HAES660) and Mauka (HAES741) were selected by the University of Hawaii—released in 1966 and 1977, respectively—and have been used extensively in macadamia orchards throughout the world. Recent molecular evidence suggests that these two cultivars are almost identical genetically; however, commercially they have been considered phenotypically different. This study reviews available molecular, historical, and phenotypic evidence to examine the hypothesis that these two cultivars are the same genotype. Phenotypic variability for morphological traits was observed in a replicated trial at Wolvi, QLD. Historical evidence suggests that both ‘HAES660’ and ‘HAES741’ were derived from the same orchard. We identified strong genetic and phenotypic similarities between these cultivars, with variability in some simple traits. This study provides evidence that these two cultivars are isogenic or near isogenic and may have been derived from the same plant source.

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Hrvoje Rukavina, Harrison Hughes, and Randy Johnson

spicata ) Genet. Resource Crop Evol. 51 687 699 Rukavina, H. 2006 Phenotypic variability, cold hardiness and flowering induction of saltgrass [ Distichlis spicata (L.) Greene] clones Colorado State University Fort

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Allan F. Brown, Elizabeth H. Jeffery, and John A. Juvik

) accounting for 54.1% of the phenotypic variability in flowering time, but curd or head formation in B. oleracea involves a complex retardation in the juvenile growth phase and flowering time alone may not fully explain or be correlated with commercial

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David C. Zlesak and Neil O. Anderson

bulbs were exposed to in the clonal cycles before shipment. Although the range in SEM among bulb lots in S2-FC2 was considerably reduced relative to S2-FC1, partitioning the phenotypic variability for SEM or any trait into its genetic, environmental, and

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Y.D. Park, A.A. Boe, and M.K. Ehlenfeldt

Leaf disks of potato cv. Kennebec and ND 860-2 (North Dakota potato breeding clone) were cultured on Murashige Skoog (MS) medium supplemented with 6 levels of indole acetic acid (IAA) and 7 levels of zeatin riboside (ZR). Shoots were induced at various combinations of hormone levels. The medium containing 3.5 mg/l IAA and 4.0 mg/l ZR produced the most shoots. Rooted plantlets were grown in the greenhouse. The growth of regenerated plants obtained from the MS medium supplemented with 7.0 mg/l IAA and 3.0 mg/l ZR was significantly greater than those grown from nodal explants. In ND 8602, a leaf chimera with chlorophyll deficient (light yellow) sectors was found in plants regenerated from leaf disks (grown on MS medium supplemented with 3.5 mg/l IAA and 3.0 mg/l ZR) but not in plants grown from nodal explants. Phenotypic variability was also observed for tuber number, size and weight.

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Laurie Hodges

A favorite garden flower for centuries, bleeding heart or old-fashioned bleeding heart (Lamprocapnos spectabilis) is also used as a potted plant and in floral arrangements. Most general gardening guides include information on growing conditions but provide few specifics regarding plant growth and development that are important to those interested in commercial cultivation and use in the floral industry. Although uncommon in the U.S. floral industry, the plant is adaptable for use as a flowering potted plant and as cut floral stems with potential for year-around availability. This report provides detailed cultural information for this audience with an overview of the history of the species and its unique characteristics. Despite the popularity of the spectacular flower and plant form, until 1997 it was only available in the common pink and white form or a pure white form and exhibited little phenotypic variability. Three new cultivars, Goldheart, Valentine, and Hordival, are now available with distinctive foliage and flower colors. These new cultivars are poised to create much interest among gardeners and cut flower growers. The history, culture, propagation, forced flowering, use as a cut flower, pest management, and pharmacological potential are presented.

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Arthur Q. Villordon and Don R. LaBonte

Polymorphism analysis and yield tests were conducted among `Jewel' sweetpotato clones [Ipomoea batatas (L.) Lam] obtained from eight state foundation seed programs. Initially, 38 arbitrary primers generated a total of 110 scorable DNA fragments in a sample of virus-indexed plants from each clone source. The number of marker loci scored for each primer varied from one to eight with an average of 2.89. Twenty-one bands (19.1%) were scored as putative polymorphic markers based on the presence or absence of amplified products. Further estimation of variability within each clone source was accomplished by an assay of 10 sample plants per clone group by 14 marker loci generated by four selected primers. Polymorphic bands ranged from 7.1% to 35.7 % in five of eight clone groups. Field studies show variation in nearly all yield grades measured. In three tests during the 1991 and 1992 seasons, yield differences ranged from 27% to 46% within the economically important U.S. no. 1 root grade. The results suggest the usefulness of arbitrarily-primed markers in detecting intra-clonal sweetpotato DNA polymorphisms and indicate an underlying genetic cause for phenotypic variability in the crop.

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Jan Tivang, Paul W. Skroch, James Nienhuis, and Neal De Vos

The magnitude of genetic differences among and heterogeneity within globe artichoke cultivars is unknown. Variation among individual heads (capitula) from three artichoke cultivars and two breeding populations were evaluated using RAPD markers. One vegetatively propagated cultivar (`Green Globe'), two seed-propagated cultivars (`Imperial Star' and `Big Heart') and two breeding populations were examined. Two to thirteen polymorphic bands were observed for 27 RAPD primers, which resulted in 178 scored bands. Variation was found within and among all cultivars, and breeding populations indicating that all five groups represent heterogeneous populations with respect to RAPD markers. The genetic relationships among individual genotypes were estimated using the ratio of discordant bands to total bands scored. Multidimensional scaling of the relationship matrix showed five independent clusters corresponding to the three cultivars and two breeding populations. The integrity of the five clusters was confirmed using pooled chi-squares for fragment homogeneity. Average gene diversity (Hs) was calculated for each population sample, and a one-way analysis of variance showed significant differences among populations. `Big Heart' had an Hs value equivalent to the two breeding populations, while clonally propagated `Green Globe' and seed propagated `Imperial Star' had the lowest Hs values. The RAPD heterogeneity observed within clonally propagated `Green Globe' is consistent with phenotypic variability observed for this cultivar. Overall, the results demonstrate the utility of the RAPD technique for evaluating genetic relationships and contrasting levels of genetic diversity among populations of artichoke genotypes.

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Khalid Ibrahim and John Juvik

Vegetables are a rich source of dietary carotenoids and tocopherols, powerful antioxidants that have the capacity to protect cells against oxidative damage caused by free radical reactions. There is evidence for a negative correlation between the incidence of certain types of cancer, age-related macular degeneration, cataract development, and cardiovascular disease with increased carotenoid and tocopherol intake. Development of elite vegetable germplasm with enhanced levels of these phytochemicals will potentially promote health among the consuming public. To assess the feasibility for genetic improvement in phytochemical content, it is necessary to partition the phenotypic variability into its component sources (genotype, environment, and genotype by environment interaction). To provide data for comparison and partition of phenotypic variation, 41 sweet corn and 13 broccoli genotypes were grown and harvested in one location for 3 years and analyzed for phytochemical content by HPLC. The most abundant form of carotenoids and tocopherols were lutein and gamma-tocopherol in sweet corn and beta-carotene and alpha-tocopherol in broccoli. Analysis of variance showed that, in sweet corn, the differences among genotypes described most of the phenotypic variation (76% for lutein, and 78% for gamma-tocopherol). Genotype by year interaction was a second significant factor, while variation affiliated with the year was found to be a minor component. In contrast, in broccoli, the three sources of variability contributed equally to describe the total phenotypic variation for beta-carotene and alpha-tocopherol. These results suggest that elite sweet corn and broccoli germplasm with improved carotenoid and tocopherol levels can be developed using conventional breeding protocols.

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Rolland Agaba, Phinehas Tukamuhabwa, Patrick Rubaihayo, Silver Tumwegamire, Andrew Ssenyonjo, Robert O.M. Mwanga, Jean Ndirigwe, and Wolfgang J. Grüneberg

The amount of genotypic and phenotypic variability that exists in a species is important for selection and initiating breeding programs. Yam bean is grown locally in tropical countries of the Americas and Asia for their tasty storage roots, which usually have low dry matter content. The crop was recently introduced in Uganda and other East and Central African countries to supplement iron (Fe) and protein content in diets. This study aimed to estimate genetic variability for root yield and quality traits among 26 yam bean accessions in Uganda. A randomized complete block design was used with two replications across two ecogeographical locations and two seasons during 2012 and 2013. Near-infrared reflectance spectroscopy (NIRS) was used to determine quality of storage root samples. Significant differences among genotypes were observed for all traits except root protein, zinc (Zn), and phosphorus contents. Genotypic variance components () were significant for storage root fresh yield (SRFY), storage root dry matter (SRDM), storage root dry yield (SRDY), vine yield (VNY), fresh biomass yield (FBY), and storage root starch (STA) and Fe contents. For traits with significant the broad sense heritability estimates ranged from 58.4% for SRDY to 83.6% for FBY; and phenotypic coefficients of variation were high for SRFY (66%), SRDY (53.3%), VNY (60.5%), and FBY (59%), but low to medium for SRDM (22.6%), STA (15.1%), and Fe (21.3%). Similarly, the genotypic coefficients of variation were high for SRFY (56.7%), SRDY (53.3%), VNY (55%), and FBY (53.9%); and low for SRDM (20%), STA (12.4%), and Fe (17.8%). There were strong positive correlations between SRFY and both SRDY (r = 0.926) and FBY (r = 0.962), but low-to-moderate correlations among quality traits. It should be possible to breed for high dry matter yam beans by using low dry matter accessions due to the observed genetic variation ( = 9.3%2), which is important if the high dry matter Pachyrhizus tuberosus accessions (known as chuin) from Peru cannot be accessed. This study indicated substantial genetic variation for yield and quality traits in yam bean, demonstrating potential for adaptability to growing conditions and consumer needs in East and Central Africa and for genetic improvement through selection.