Field Evaluations of Herbicides on Vegetable, Small Fruit, and Ornamental Crops, 2000, 2001, & 2002

Field evaluations of herbicides provide the chemical industry, governmental agencies, such as IR-4, and the Arkansas Agricultural Experiment Station with an evaluation of herbicide performance on small fruit, vegetable, and ornamental crops grown under Arkansas conditions. This report provides a means for disseminating information to interested private and public service weed scientists

Field Evaluation of Herbicides on Small Fruit, Vegetable, and Ornamental Crops, 1998

Growers generally use herbicides to efficiently produce high-quality fruit and vegetables for processing or fresh market sales. Due to the smaller acreage of these crops compared to major field crops, fewer herbicides are registered for use in fruit and vegetable crops than for field crops. Each year, new herbicides are evaluated under Arkansas growing conditions with the objective of improving the herbicide technology for the grower, processor, and ultimately the consumer. This report includes studies on the control of many of the more serious weed problems in important crops of this region, including snapbeans, spinach, southernpeas, watermelon, cantaloupe, summer squash, and grapes. In addition, the report includes information on the tolerance of selected bedding plants to some effective herbicides

Field Evaluation of Herbicides on Small Fruit, Vegetable, and Ornamental Crops, 1999

Growers generally use herbicides to efficiently produce high-quality fruit and vegetables for processing or fresh market sales. Because of the smaller acreage of these crops compared with major field crops, fewer herbicides are registered for use in fruit and vegetable crops than for field crops. Each year, new herbicides are evaluated under Arkansas growing conditions with the objective of improving the herbicide technology for the grower, processor, and ultimately the consumer. This report includes studies on the control of many of the more serious weed problems in important crops of this region, including snapbeans, spinach and other greens, southernpeas, tomatoes, and grapes

A haplotype map of allohexaploid wheat reveals distinct patterns of selection on homoeologous genomes

BACKGROUND: Bread wheat is an allopolyploid species with a large, highly repetitive genome. To investigate the impact of selection on variants distributed among homoeologous wheat genomes and to build a foundation for understanding genotype-phenotype relationships, we performed population-scale re-sequencing of a diverse panel of wheat lines. RESULTS: A sample of 62 diverse lines was re-sequenced using the whole exome capture and genotyping-by-sequencing approaches. We describe the allele frequency, functional significance, and chromosomal distribution of 1.57 million single nucleotide polymorphisms and 161,719 small indels. Our results suggest that duplicated homoeologous genes are under purifying selection. We find contrasting patterns of variation and inter-variant associations among wheat genomes; this, in addition to demographic factors, could be explained by differences in the effect of directional selection on duplicated homoeologs. Only a small fraction of the homoeologous regions harboring selected variants overlapped among the wheat genomes in any given wheat line. These selected regions are enriched for loci associated with agronomic traits detected in genome-wide association studies. CONCLUSIONS: Evidence suggests that directional selection in allopolyploids rarely acted on multiple parallel advantageous mutations across homoeologous regions, likely indicating that a fitness benefit could be obtained by a mutation at any one of the homoeologs. Additional advantageous variants in other homoelogs probably either contributed little benefit, or were unavailable in populations subjected to directional selection. We hypothesize that allopolyploidy may have increased the likelihood of beneficial allele recovery by broadening the set of possible selection targets

Interferencia del bledo (Amaranthus hybridus L.) sobre la calidad de la habichuela tierna (Phaseolus vulgaris L.)

Field experiments were conducted at Fayetteville, Arkansas, in spring and fail of 1989 and 1990 to determine the effect of smooth pigweed density and the duration of interference on snap bean quality. Pod length, percentage of fiber, seed weight, sloughing, pod firmness and color of snap bean were not affected by smooth pigweed densities, which ranged from 0 to 75 plants per square meter. Smooth pigweed interference for 38 days increased snap bean pod fiber and firmness. Full-season interference (for 49 days after emergence) delayed snap bean pod maturity. To prevent delay in pod maturity, smooth pigweed should be controlled 28 days after snap bean emergence or before snap bean bloom.Varios experimentos de campo se realizaron en Fayetteville, Arkansas, durante el verano y la primavera del 1989 y 1990 para determinar el efecto de las densidades de bledo y la duración de su interferencia sobre la calidad de la habichuela tierna. Las densidades del bledo (0 a 75 plantas por metro cuadrado) no afectaron el largo de la vaina, el porcentaje de fibra, el peso de las semillas, la firmeza de la vaina ni el color de la vaina. La interferencia del bledo durante los primeros 38 días después de la emergencia de la habichuela aumentó la fibra y la firmeza de la vaina de habichuela. La interferencia durante toda la época de crecimiento (por 49 días después de la emergencia) retardó la madurez de la habichuela. Para evitar la madurez tardía de las vainas, el bledo debe ser controlado 28 días después de la emergencia o antes de la florecida de la habichuela