In order to effectively use recurrent selection for developing polygenic resistance to powdery mi... more In order to effectively use recurrent selection for developing polygenic resistance to powdery mildew (Erysiphe cichoracearum), methods to quantify resistance need to be developed. Our objective was to compare several inoculation methods for their effectiveness in a half-sib selection breeding program. Seven inoculation methods and 3 controls were applied to each of two susceptible C. moschata varieties planted in pots and arranged in a randomized complete block design with five replications. The experiment was repeated two times. Single degree of freedom comparisons found no difference in number of lesions resulting from inoculation by rubbing host with infected tissue vs. attaching infected tissue. Using no adherent resulted in as many lesions as using triton. Egg white as an adherent resulted in fewer lesions than using triton or no adherent. Spraying with a triton spore suspension was not an effective method. While rubbing leaves is fast and easy, attaching pieces of infected ti...
The Journal of Agriculture of the University of Puerto Rico
Cucúrbita moschata Duchesne 'Soler' is an open-pollinated tropical pumpkin cultivar released in J... more Cucúrbita moschata Duchesne 'Soler' is an open-pollinated tropical pumpkin cultivar released in June 2004 by the Agricultural Experiment Station of the University of Puerto Rico. Tropical pumpkin, locally known as calabaza, is an important vegetable crop in the humid tropics. It is widely grown in the Caribbean, including Puerto Rico and southern Florida (Maynard et al., 1995). In Puerto Rico, production of tropical pumpkin has remained fairly steady over the past 10 years, fluctuating around 16,000 t (350,000 hundredweight) (Alamo, 2003; Anonymous, 2002). Farm gate value has been between $6 and $10 million. Soler has been well received by growers in Puerto Rico and is already being widely grown. Origin Soler was developed from three cycles of mass selection. Cycle 0 was an open-pollinated seed sample obtained in 1989 from the farm of Mario Soler near Salinas, Puerto Rico. The original seed sample was given the experimental designation PRB-150. In February 1990, the seed of PRB-150 (cycle 0 seed) was planted in isolation at the Fortuna Substation, Juana Díaz, Puerto Rico. A total of 81 fruits were selected and their seed bulked (cycle 1 seed). Selected fruits had a dark green rind and thick yellow-orange flesh, and were flat and slightly ribbed. Seed from selected fruits was planted in isolation in May 1992 at the Isabela Substation. Seed was bulked from a total of 70 fruits (cycle 2 seed) that were mass selected as described above, except that all selected fruits weighed from 4.5 to 9 kg, measured 25 to 32 cm in diameter, and exhibited a blossom-end scar no larger than 3 cm in diameter. In December 1993, seed from selected fruit was planted in isolation at the Isabela Substation. Seed (cycle 3 seed) was bulked from fruits selected as described for cycle 2. In June 2003, approximately 1,800 plants were grown in isolation from cycle 3 seed. Approximately 5% of the fruit was deemed off-types or too immature to produce good quality seed. Except for these culls, all other fruit was harvested for seed. The seed was bulked and designated as breeder's seed. Botanical Description Fruits of Soler are flat and slightly ribbed. The skin (non-lignified rind) is dark green, although areas of the fruit exposed to the sun will turn orange at maturity. In samples
Rows of tropical pumpkins (Cucurbita moschata) are typically spaced 3-4 m apart Rows fill in 8 to... more Rows of tropical pumpkins (Cucurbita moschata) are typically spaced 3-4 m apart Rows fill in 8 to 10 weeks after planting, potentially allowing a short-seasoned intercrop to be planted. A long-vine cultivar (PRB-150) and a short vine genotype (FL-I25×I21 - winter planting; FL-I25 - fall) were planted 0.9 m within rows by 1.8 between rows in Lajas and Isabela, PR in winter and fall of 1993. Either beans, cowpeas or no intercrop were planted on the same date as the pumpkin maincrop. Legume plots were harvested both green-shelled and dry. Pumpkin canopy cover, yield, fruit number and size were the same in intercropped and non-intercropped plots These same traits varied significantly in short vs. long vine plots (short vine plots were lower yielding with smaller fruits and less canopy cover). Plots planted with the short-vine maincrop generally produced greater legume yields. Harvest of dry beans or cowpeas was nearly impossible in long vine plots since the canopy covered the legume pla...
The Journal of Agriculture of the University of Puerto Rico
Minimally processed tropical pumpkin (Cucurbita moschata) has considerable potential to create ne... more Minimally processed tropical pumpkin (Cucurbita moschata) has considerable potential to create new value-added market opportunities for Puerto Rico. The aim of this work was to evaluate the quality and microbiological changes of minimally processed tropical pumpkin packed in low-density polyethylene (LDPE) bags and stored for 20 days. Pumpkin pieces approximately 2 cm3 in size were obtained from two cultivars (Taina Dorada' and 'Soler'). Pieces were immersed in an antimicrobial solution containing citric acid (0.2%) and sodium benzoate (0.1%) for 3 min, centrifuged in a salad spinner, packed in LDPE bags with either vacuum or non-vacuum packaging, and stored at 4° C ± 2 for a period of 20 days. There were minimum effects of storage time on the chemical and physical characteristics of the pumpkin pieces. The percentage of O2 decreased continuously in non-vacuum packaging while the percentage of CO2 increased within the first 72 hours of storage. A sensorial panel judged p...
HortScience: a publication of the American Society for Horticultural Science
Bulgaria is famous for its 330-year-old-tradition in rose oil production, which is based on the K... more Bulgaria is famous for its 330-year-old-tradition in rose oil production, which is based on the Kazanluk rose (Rosa damascena Mill. f. trigintipetala Dieck.). The Bulgarian rose oil (otto) is recognized as the ultimate rose oil. For successful selection and breeding work of oil-bearing roses, information is needed on the variation of morphological and phenological characteristics and essential oil composition of locally available genotypes. We estimated the correlation coefficients between yields and morphological characteristics of 15 genotypes of Bulgarian oil-bearing rose. It was found that rose yields depended mostly on the number of flowers, the number of flower branches per bush, and the weight of individual flowers (r = 0.99, 0.88, and 0.84, respectively). Also, we established correlations between the concentrations of various essential oil constituents of the Bulgarian rose oil. Generally, higher concentration of citronellol + nerol was associated with lower concentration of geraniol and stereo-terpens (r = -0.76 and -0.59, respectively). Also, higher concentration of citronellol + nerol was positively correlated to increased concentration of terpene aldehydes (r = 0.63) and esters (r = 0.48). The geraniol concentration was positively correlated to stearoptenes (r = 0.57). Both morphological characteristics and essential oil constituents should be used for further selection of high-yielding cultivars with desirable essential oil composition.
Most cultivars of tropical pumpkin (Cucurbita moschata Duchesne) are large, trailing plants. New ... more Most cultivars of tropical pumpkin (Cucurbita moschata Duchesne) are large, trailing plants. New semi-bush (SB) genotypes need to be tested against traditional long vine (LV) types. Both types of pumpkin have large amounts of interplant space during the early stages of growth that might allow for the planting of an intercrop. To test this hypothesis, as well as the performance of tropical pumpkins of varying growth habit, double rows of beans (Phaseolus vulgaris L.) or cowpeas [Vigna unguiculata (L.) Walp.]
Viruses that affect crops have been intensively studied, but its unknown how these viruses affect... more Viruses that affect crops have been intensively studied, but its unknown how these viruses affect non-cultivated plants. To develop the best strategies for crop protection, the diversity of viruses in non-cultivated plants needs to be understood. This work focuses on the occurrence of potyvirus in Momordica (Cucurbitaceae), an wild naturalized vine in Puerto Rico. We sampled 347 Momordica plants across Puerto Rico including adjacent islands of Culebra and Vieques. We used an enzyme-linked immunosorbent assay for detection of potyviruses and RT-PCR to amplify the CP region using MJ1 and MJ2 primers. Maps of both symptomatic and asymptomatic plants were developed using the species distribution model algorithm MaxEnt and screening of 20 environmental variables for the most informative layers inferring potential places of occurrence. The viruses PRSV and ZYMV were the most commonly encountered potyviruses. The presence of disease symptoms in Momordica was closely associated with the occ...
Proceedings of the National Academy of Sciences, 2002
Many angiosperms, both monocotyledons and dicotyledons, heavily impregnate their vegetative and r... more Many angiosperms, both monocotyledons and dicotyledons, heavily impregnate their vegetative and reproductive organs with solid particles of silicon dioxide (SiO 2) known as opaline phytoliths. The underlying mechanisms accounting for the formation of phytoliths in plants are poorly understood, however. Using wild and domesticated species in the genus Cucurbita along with their F 1 and F2 progeny, we have demonstrated that the production of large diagnostic phytoliths in fruit rinds exhibits a one-to-one correspondence to the lignification of these structures. We propose that phytolith formation in Cucurbita fruits is primarily determined by a dominant genetic locus, called hard rind (Hr), previously shown to code for lignin deposition. If true, this evidence represents a demonstration of genetic control over phytolith production in a dicotyledon and provides considerable support to hypotheses that silica phytoliths constitute another important system of mechanical defense in plants. Our research also identifies Hr as another single locus controlling more than one important phenotypic difference between wild and domesticated plants, and establishes rind tissue cell structure and hardness under the effects of Hr as an important determinant of phytolith morphology. When recovered from pre-Columbian archaeological sites, Cucurbita phytoliths represent genetically controlled fossil markers of exploitation and domestication in this important economic genus.
Proceedings of the National Academy of Sciences, 2002
We have investigated the phylogenetic relationships among six wild and six domesticated taxa of C... more We have investigated the phylogenetic relationships among six wild and six domesticated taxa of Cucurbita using as a marker an intron region from the mitochondrial nad1 gene. Our study represents one of the first successful uses of a mtDNA gene in resolving inter-and intraspecific taxonomic relationships in Angiosperms and yields several important insights into the origins of domesticated Cucurbita. First, our data suggest at least six independent domestication events from distinct wild ancestors. Second, Cucurbita argyrosperma likely was domesticated from a wild Mexican gourd, Cucurbita sororia, probably in the same region of southwest Mexico that gave rise to maize. Third, the wild ancestor of Cucurbita moschata is still unknown, but mtDNA data combined with other sources of information suggest that it will probably be found in lowland northern South America. Fourth, Cucurbita andreana is supported as the wild progenitor of Cucurbita maxima, but humid lowland regions of Bolivia in addition to warmer temperate zones in South America from where C. andreana was originally described should possibly be considered as an area of origin for C. maxima. Fifth, our data support other molecular results that indicate two separate domestications in the Cucurbita pepo complex. The potential zone of domestication for one of the domesticated subspecies, C. pepo subsp. ovifera, includes eastern North America and should be extended to northeastern Mexico. The wild ancestor of the other domesticated subspecies, C. pepo subsp. pepo, is undiscovered but is closely related to C. pepo subsp. fraterna and possibly will be found in southern Mexico.
In order to effectively use recurrent selection for developing polygenic resistance to powdery mi... more In order to effectively use recurrent selection for developing polygenic resistance to powdery mildew (Erysiphe cichoracearum), methods to quantify resistance need to be developed. Our objective was to compare several inoculation methods for their effectiveness in a half-sib selection breeding program. Seven inoculation methods and 3 controls were applied to each of two susceptible C. moschata varieties planted in pots and arranged in a randomized complete block design with five replications. The experiment was repeated two times. Single degree of freedom comparisons found no difference in number of lesions resulting from inoculation by rubbing host with infected tissue vs. attaching infected tissue. Using no adherent resulted in as many lesions as using triton. Egg white as an adherent resulted in fewer lesions than using triton or no adherent. Spraying with a triton spore suspension was not an effective method. While rubbing leaves is fast and easy, attaching pieces of infected ti...
The Journal of Agriculture of the University of Puerto Rico
Cucúrbita moschata Duchesne 'Soler' is an open-pollinated tropical pumpkin cultivar released in J... more Cucúrbita moschata Duchesne 'Soler' is an open-pollinated tropical pumpkin cultivar released in June 2004 by the Agricultural Experiment Station of the University of Puerto Rico. Tropical pumpkin, locally known as calabaza, is an important vegetable crop in the humid tropics. It is widely grown in the Caribbean, including Puerto Rico and southern Florida (Maynard et al., 1995). In Puerto Rico, production of tropical pumpkin has remained fairly steady over the past 10 years, fluctuating around 16,000 t (350,000 hundredweight) (Alamo, 2003; Anonymous, 2002). Farm gate value has been between $6 and $10 million. Soler has been well received by growers in Puerto Rico and is already being widely grown. Origin Soler was developed from three cycles of mass selection. Cycle 0 was an open-pollinated seed sample obtained in 1989 from the farm of Mario Soler near Salinas, Puerto Rico. The original seed sample was given the experimental designation PRB-150. In February 1990, the seed of PRB-150 (cycle 0 seed) was planted in isolation at the Fortuna Substation, Juana Díaz, Puerto Rico. A total of 81 fruits were selected and their seed bulked (cycle 1 seed). Selected fruits had a dark green rind and thick yellow-orange flesh, and were flat and slightly ribbed. Seed from selected fruits was planted in isolation in May 1992 at the Isabela Substation. Seed was bulked from a total of 70 fruits (cycle 2 seed) that were mass selected as described above, except that all selected fruits weighed from 4.5 to 9 kg, measured 25 to 32 cm in diameter, and exhibited a blossom-end scar no larger than 3 cm in diameter. In December 1993, seed from selected fruit was planted in isolation at the Isabela Substation. Seed (cycle 3 seed) was bulked from fruits selected as described for cycle 2. In June 2003, approximately 1,800 plants were grown in isolation from cycle 3 seed. Approximately 5% of the fruit was deemed off-types or too immature to produce good quality seed. Except for these culls, all other fruit was harvested for seed. The seed was bulked and designated as breeder's seed. Botanical Description Fruits of Soler are flat and slightly ribbed. The skin (non-lignified rind) is dark green, although areas of the fruit exposed to the sun will turn orange at maturity. In samples
Rows of tropical pumpkins (Cucurbita moschata) are typically spaced 3-4 m apart Rows fill in 8 to... more Rows of tropical pumpkins (Cucurbita moschata) are typically spaced 3-4 m apart Rows fill in 8 to 10 weeks after planting, potentially allowing a short-seasoned intercrop to be planted. A long-vine cultivar (PRB-150) and a short vine genotype (FL-I25×I21 - winter planting; FL-I25 - fall) were planted 0.9 m within rows by 1.8 between rows in Lajas and Isabela, PR in winter and fall of 1993. Either beans, cowpeas or no intercrop were planted on the same date as the pumpkin maincrop. Legume plots were harvested both green-shelled and dry. Pumpkin canopy cover, yield, fruit number and size were the same in intercropped and non-intercropped plots These same traits varied significantly in short vs. long vine plots (short vine plots were lower yielding with smaller fruits and less canopy cover). Plots planted with the short-vine maincrop generally produced greater legume yields. Harvest of dry beans or cowpeas was nearly impossible in long vine plots since the canopy covered the legume pla...
The Journal of Agriculture of the University of Puerto Rico
Minimally processed tropical pumpkin (Cucurbita moschata) has considerable potential to create ne... more Minimally processed tropical pumpkin (Cucurbita moschata) has considerable potential to create new value-added market opportunities for Puerto Rico. The aim of this work was to evaluate the quality and microbiological changes of minimally processed tropical pumpkin packed in low-density polyethylene (LDPE) bags and stored for 20 days. Pumpkin pieces approximately 2 cm3 in size were obtained from two cultivars (Taina Dorada' and 'Soler'). Pieces were immersed in an antimicrobial solution containing citric acid (0.2%) and sodium benzoate (0.1%) for 3 min, centrifuged in a salad spinner, packed in LDPE bags with either vacuum or non-vacuum packaging, and stored at 4° C ± 2 for a period of 20 days. There were minimum effects of storage time on the chemical and physical characteristics of the pumpkin pieces. The percentage of O2 decreased continuously in non-vacuum packaging while the percentage of CO2 increased within the first 72 hours of storage. A sensorial panel judged p...
HortScience: a publication of the American Society for Horticultural Science
Bulgaria is famous for its 330-year-old-tradition in rose oil production, which is based on the K... more Bulgaria is famous for its 330-year-old-tradition in rose oil production, which is based on the Kazanluk rose (Rosa damascena Mill. f. trigintipetala Dieck.). The Bulgarian rose oil (otto) is recognized as the ultimate rose oil. For successful selection and breeding work of oil-bearing roses, information is needed on the variation of morphological and phenological characteristics and essential oil composition of locally available genotypes. We estimated the correlation coefficients between yields and morphological characteristics of 15 genotypes of Bulgarian oil-bearing rose. It was found that rose yields depended mostly on the number of flowers, the number of flower branches per bush, and the weight of individual flowers (r = 0.99, 0.88, and 0.84, respectively). Also, we established correlations between the concentrations of various essential oil constituents of the Bulgarian rose oil. Generally, higher concentration of citronellol + nerol was associated with lower concentration of geraniol and stereo-terpens (r = -0.76 and -0.59, respectively). Also, higher concentration of citronellol + nerol was positively correlated to increased concentration of terpene aldehydes (r = 0.63) and esters (r = 0.48). The geraniol concentration was positively correlated to stearoptenes (r = 0.57). Both morphological characteristics and essential oil constituents should be used for further selection of high-yielding cultivars with desirable essential oil composition.
Most cultivars of tropical pumpkin (Cucurbita moschata Duchesne) are large, trailing plants. New ... more Most cultivars of tropical pumpkin (Cucurbita moschata Duchesne) are large, trailing plants. New semi-bush (SB) genotypes need to be tested against traditional long vine (LV) types. Both types of pumpkin have large amounts of interplant space during the early stages of growth that might allow for the planting of an intercrop. To test this hypothesis, as well as the performance of tropical pumpkins of varying growth habit, double rows of beans (Phaseolus vulgaris L.) or cowpeas [Vigna unguiculata (L.) Walp.]
Viruses that affect crops have been intensively studied, but its unknown how these viruses affect... more Viruses that affect crops have been intensively studied, but its unknown how these viruses affect non-cultivated plants. To develop the best strategies for crop protection, the diversity of viruses in non-cultivated plants needs to be understood. This work focuses on the occurrence of potyvirus in Momordica (Cucurbitaceae), an wild naturalized vine in Puerto Rico. We sampled 347 Momordica plants across Puerto Rico including adjacent islands of Culebra and Vieques. We used an enzyme-linked immunosorbent assay for detection of potyviruses and RT-PCR to amplify the CP region using MJ1 and MJ2 primers. Maps of both symptomatic and asymptomatic plants were developed using the species distribution model algorithm MaxEnt and screening of 20 environmental variables for the most informative layers inferring potential places of occurrence. The viruses PRSV and ZYMV were the most commonly encountered potyviruses. The presence of disease symptoms in Momordica was closely associated with the occ...
Proceedings of the National Academy of Sciences, 2002
Many angiosperms, both monocotyledons and dicotyledons, heavily impregnate their vegetative and r... more Many angiosperms, both monocotyledons and dicotyledons, heavily impregnate their vegetative and reproductive organs with solid particles of silicon dioxide (SiO 2) known as opaline phytoliths. The underlying mechanisms accounting for the formation of phytoliths in plants are poorly understood, however. Using wild and domesticated species in the genus Cucurbita along with their F 1 and F2 progeny, we have demonstrated that the production of large diagnostic phytoliths in fruit rinds exhibits a one-to-one correspondence to the lignification of these structures. We propose that phytolith formation in Cucurbita fruits is primarily determined by a dominant genetic locus, called hard rind (Hr), previously shown to code for lignin deposition. If true, this evidence represents a demonstration of genetic control over phytolith production in a dicotyledon and provides considerable support to hypotheses that silica phytoliths constitute another important system of mechanical defense in plants. Our research also identifies Hr as another single locus controlling more than one important phenotypic difference between wild and domesticated plants, and establishes rind tissue cell structure and hardness under the effects of Hr as an important determinant of phytolith morphology. When recovered from pre-Columbian archaeological sites, Cucurbita phytoliths represent genetically controlled fossil markers of exploitation and domestication in this important economic genus.
Proceedings of the National Academy of Sciences, 2002
We have investigated the phylogenetic relationships among six wild and six domesticated taxa of C... more We have investigated the phylogenetic relationships among six wild and six domesticated taxa of Cucurbita using as a marker an intron region from the mitochondrial nad1 gene. Our study represents one of the first successful uses of a mtDNA gene in resolving inter-and intraspecific taxonomic relationships in Angiosperms and yields several important insights into the origins of domesticated Cucurbita. First, our data suggest at least six independent domestication events from distinct wild ancestors. Second, Cucurbita argyrosperma likely was domesticated from a wild Mexican gourd, Cucurbita sororia, probably in the same region of southwest Mexico that gave rise to maize. Third, the wild ancestor of Cucurbita moschata is still unknown, but mtDNA data combined with other sources of information suggest that it will probably be found in lowland northern South America. Fourth, Cucurbita andreana is supported as the wild progenitor of Cucurbita maxima, but humid lowland regions of Bolivia in addition to warmer temperate zones in South America from where C. andreana was originally described should possibly be considered as an area of origin for C. maxima. Fifth, our data support other molecular results that indicate two separate domestications in the Cucurbita pepo complex. The potential zone of domestication for one of the domesticated subspecies, C. pepo subsp. ovifera, includes eastern North America and should be extended to northeastern Mexico. The wild ancestor of the other domesticated subspecies, C. pepo subsp. pepo, is undiscovered but is closely related to C. pepo subsp. fraterna and possibly will be found in southern Mexico.
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