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Plant materials. One hundred and fourteen PIs comprised lines derived from accessions and landraces through inbreeding, open-pollinated lines released by the World Vegetable Center, and commercial hybrid cultivars, collectively referred to as cultigens

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Abstract

The zonal geranium, Pelargonium X hortorum Bailey2, probably originated from hybridization of natural species of the subgenus Ciconium (Sweet) Harvey of the genus Pelargonium l’Her. ex Ait. (11, 25). Although P. zonale was introduced into Europe from South Africa in 1609, it was not until 1814 that other Pelargonium species reached Europe. Since interspecific hybridization is readily accomplished under greenhouse conditions, the plant breeders of the time soon produced a number of forms different from the wild species (10, 11). Pelargonium breeding has, therefore, been carried out for over 150 years and, as few records have been kept until quite recently, the problem of species classification and determining the phylogeny of the culti-gens is difficult (28).

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Hybrids from crosses between bush/short-vined breeding lines and traditional, vining cultigens were evaluated in the fall 1993 season. Yields of individual hybrids were 0.51 to 1.73 times those of their vining parents and 0.83 to 4.41 times those of the bush/short-vined parents. The average yield response of 58 hybrids was 1.05 times that of vining parents and 2.15 that of bush/short-vined parents. Average fruit weight, flesh thickness, and flesh color of the hybrids tended to be intermediate between that of the bush/short-vined and vining parents. Plant habit of all hybrids was similar to that of the bush/short-vined parent early in the growth cycle, but some became viney later in the growth cycle. Fruit matured earlier on bush/short-vined parent and hybrid plants than on viney parent plants.

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Rotting muskmelon fruits commonly are associated with commercial fields that are affected by the root rot/vine decline disease syndrome found in southern Texas. Four isolates of Fusarium solani previously shown to be either weakly pathogenic or nonpathogenic to muskmelon seedlings caused extensive rot on mechanically wounded muskmelon fruits. Two of these isolates caused more extensive fruit rot than either F. solani (Mart.) Sacc. f. sp. cucurbitae W.C. Snyder & H.N. Hans. or F. oxysporum Schlechtend.:Fr. melonis (Leach & Currence) W.C. Snyder & H.N. Hans., causal agents of fusarium crown and foot rot of cucurbits and fusarium wilt of muskmelon, respectively. In other tests, root-dip inoculation of seedlings showed that all muskmelon cultigens included in this study and the breeding line MR-1 were susceptible to a California and an Arkansas strain of F. s. f. sp. cucurbitae race 1.

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Ten tomato cultigens were crossed with L. peruvianum accessions PI 126443 and PI 129152. Fruit (536 total) were harvested between 15 and 65 days after anthesis (DAA). Culturable embryos were obtained from 13% of the fruit. There were 140 embryos plated, from which 36 plants were obtained (7% of fruit, 26% of embryos plated). 'Campbell 28', Fla. 7217, and Fla. 7182 were the most efficient tomato lines for producing F1 plants, there was no difference between the L. peruvianum accessions. No embryos were obtained beyond 57 DAA. No trend in embryo viability was detected between 15 and 56 DAA. Of 248 backcross fruit, 94 embryos were plated (38% of fruit) and 15 plants were obtained (6% of fruit, 16% of embryos plated). Female parents with the best percentage of plants per fruit crossed were Fla. 7217, Fla. 7215, and 'Campbell 28' with 15, 8, and 7%, respectively. No plants were obtained from 45 crosses on Fla. 7182.

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Seed of 42 wild accessions (Plant Introductions) of Lycopersicon pimpinellifolium Jusl., 11 cultigens (cultivated accessions) of L. esculentum Mill., and three control genotypes [LA716 (a salt-tolerant wild accession of L. pennellii Corr.), PI 174263 (a salt-tolerant cultigen), and UCT5 (a salt-sensitive breeding line)] were evaluated for germination in either 0 mm (control) or 100 mm synthetic sea salt (SSS, Na+/Ca2+ molar ratio equal to 5). Germination time increased in response to salt-stress in all genotypes, however, genotypic variation was observed. One accession of L. pimpinellifolium, LA1578, germinated as rapidly as LA716, and both germinated more rapidly than any other genotype under salt-stress. Ten accessions of L. pimpinellifolium germinated more rapidly than PI 174263 and 35 accessions germinated more rapidly than UCT5 under salt-stress. The results indicate a strong genetic potential for salt tolerance during germination within L. pimpinellifolium. Across genotypes, germination under salt-stress was positively correlated (r = 0.62, P < 0.01) with germination in the control treatment. The stability of germination response at diverse salt-stress levels was determined by evaluating germination of a subset of wild, cultivated accessions and the three control genotypes at 75, 150, and 200 mm SSS. Seeds that germinated rapidly at 75 mm also germinated rapidly at 150 mm salt. A strong correlation (r = 0.90, P < 0.01) existed between the speed of germination at these two salt-stress levels. At 200 mm salt, most accessions (76%) did not reach 50% germination by 38 days, demonstrating limited genetic potential within Lycopersicon for salt tolerance during germination at this high salinity.

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In the article, Heritability and Genetic Variance Components Associated with Citrulline, Arginine and Lycopene Content in Diverse Watermelon Cultigens by Wehner et al. [HortScience 52(7):936–940 doi: 10.21273/HORTSCI11255-16], there was a mistake in

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Twenty-two southernpea (Vigna unguiculata L. Walp.) cultigens were evaluated in field plots in southern, central, and northern Alabama to establish a set of varieties that would reach harvest stage sequentially. As first pods reached the dry stage, subjective ratings were made to estimate percentages of the following pod maturity stages: presnap, snap, mature green, and dry. Mature-green and dry stages were combined to give the total percentage of mature pods. From a general linear model analysis on SAS, lines were highly significant sources of variation in percentage of mature pods up to 83 days after planting. At least three maturity groups were apparent: >80%, 50% to 80%, and <50% mature pods. These are represented by `Santee Early Pinkeye', `Coronet', `Texas Pinkeye', and `Pinkeye Purplehull BVR'; `C.T. Pinkeye Purplehull', `Epoch', and `Pinkeye Pinkpod'; and `Mississippi Pinkeye' and `Corona', respectively. All the plant introductions were in the late category and generally are not characteristic of commercial pinkeyes; they may be valuable in breeding for lateness in southernpeas.

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Principal component analyses of variation at 21 isozyme and 43 random amplified polymorphic DNA (RAPD) loci in eight cucumber (GY-14a, G421, H-19, WI 2757, and PIs 432860, 458845, and 183967) and seven melon [Top Mark (TM), Doublon, Green Flesh Honeydew (GFH), Juane Canari (JC), Freeman cucumber (FC), Snakemelon (SM), and PI 124111] cultigens were used to determine the use of these markers for assessing genetic variation among and within populations of each species (outgroup = Cucumis metuliferus). RAPD and isozyme marker variation was related to previous taxonomic classification and available pedigree information. Although dendrograms derived from cluster analyses using species' variation at marker loci were dissimilar, these disparities were consistent with differences in the pedigrees and/or other information (e.g., morphological) known about each accession and species. Elite U.S. processing cucumbers (G421, GY-14a, and H-19) shared distinctive biochemical affinities. Doublon was differentiated from TM, GFH, and JC. Doublon had biochemical affinities with FC, SM, and PI 124111.

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Cucumber (Cucumis sativus L.) is one of the more chilling sensitive crops. Chilling resistance could provide growers with protection against late spring frost. Significant differences for chilling resistance were observed among a set of 9 diverse cucumber cultigens when grown at 22 C to 1st true leaf stage, then given a chilling treatment of 4 C for 7 hours in full light (PPFD 500 μmol.m-2.s-1). Two populations, NCWBP and NCES1, were used to measure narrow-sense heritability (estimated as twice the parent-offspring regression coefficient) for chilling resistance. Sets (256/population) of parents and offspring were evaluated in separate tests for seedling resistance. Plants were rated for damage 0 (none) to 9 (dead) on the cotyledons and 1st true leaf, 3 and 5 days after chilling. Ratings were corrected for position in the Phytotron chamber, and log transformations used to normalize the data. Generally, correction reduced the heritability estimates and transformation improved them. Heritability was highest for cotyledon ratings made 5 days after chilling, ranging from 0.35 for NCWBP to 0.70 for NCES1. Ratings of the 1st true leaf were more difficult to make, and produced lower estimates of heritability. Breeders should be able to make good progress in selecting for chilling resistance using this seedling test.

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