Search Results
Mulch (black plastic, wheat straw, or bare ground) and irrigation (drip or overhead sprinkler) treatments were evaluated for their effect on center rot of onion (Allium cepa L.), caused by the bacterium Pantoea ananatis, over the course of two seasons. Irrigation type had no effect on center rot incidence or severity in either year. In contrast, center rot development was delayed by 7 to 14 days on onions grown in straw mulch or bare ground compared to those in black plastic. Straw mulch resulted in later harvest dates and was associated with reduced levels of center rot. In contrast, black plastic increased disease incidence and hastened the onset of the epidemic. The spatial distribution of disease incidence in both years indicated the presence of a primary disease gradient. At harvest, infected plants were segregated by treatment and by duration of infection [based on disease ratings taken from the time of first symptom expression (beginning at 110 to 120 days after transplanting and then every 5 to 10 days until harvest)]. Early-vs. late-infected plants had no significant effect on yield (bulb weight). However, symptom expression in terms of the number of days after planting was significantly correlated with a disease severity index. Amount of rot in bulbs from plants displaying their first symptoms only 1 to 2 days before harvest (late-season infection) was not significant from rot levels in control bulbs at harvest. However, at 4 weeks after harvest, onions from plants with late-season infections exhibited significantly more rot in storage compared to the control.
Abstract
Bacterial wilt or brown rot caused by Pseudomonas solanaceamm E.F. Sm. is a major limiting factor of potato (Solanum tuberosum L.) production in the warm, humid regions of the world, including the coastal plain region of southeastern United States (5).
Abstract
Potato (Solanum tuberosum L.), the most important dicotyledonous food crop in the world, is grown mostly under temperate climatic conditions and is usually planted vegetatively with tubers (often called “seed” tubers) (12). Use of seed tubers for potato production has many advantages, including ease of planting, vigorous plant growth, uniform tubers, and high tuber yields (27). However, with increased interest in production of potatoes in warm regions, use of seed tubers often becomes costly and has disadvantages (1, 2, 23, 27, 30). Some of the disadvantages of seed tubers in warm or developing regions of the world are: there is a lack of seed tuber certification programs; imported seed tubers are expensive; seed tubers often are contaminated with plant pathogens and other pests; and available potato cultivars often are not adapted to warm regions (2, 18, 19). Consequently, during the past decade, research efforts on adopting true potato seed (TPS) instead of seed tubers for potato production were initiated in many areas of the world (5, 8, 16, 17, 20).
Abstract
Although extensive research is currently being conducted related to true potato seed (TPS) in the areas of breeding, production, and cultural practices (1, 3, 4, 5), there is little information generated on the engineering aspects of potato production from TPS. Potato production from TPS varies greatly from current methods in which potatoes are grown from tubers. Potatoes can be produced from TPS in three different ways: 1) seeding TPS in rows to produce potatoes similar to other crops produced by direct seeding; 2) planting TPS to raise transplants for planting in another field; and 3) using TPS for the production of seedling tubers to be used like “seed” tubers. Mechanization needs for each of these TPS uses are different. It might be necessary to modify the existing equipment or develop new equipment to meet specific needs of using TPS. Equipment needs for potato production from TPS in developing countries also will need special consideration. Engineering research conducted at the Georgia Coastal Plain Experiment Station, related to potato production from TPS has been reported in detail by Ghate et al. (2). Since that publication, we have concentrated our research efforts in the direction of the equipment needs for TPS use in developing countries.
Abstract
Bacterial wilt or brown rot caused by Pseudomonas solanacearum E. F. Sm. is a major limiting factor in potato (Solanum tuberosum L.) production in the warm, humid regions of the world, including the coastal plain region of southeastern United States (6, 7).
Abstract
Bacterial wilt, caused by the soil-borne pathogen Pseudomonas solanacearum E, F. Sm., causes major economic losses in tomato (Lycopersicon esculentum Mill.) production in many warm, humid regions of the world (6, 8). Selections of L. esculentum (GA 1565-2-4 BWT, GA 219-1-2 BWT and GA 1095-1-4 BWT) and of L. esculentum × L. pimpinellifolium (Jusl.) Mill. (GA 14051-2 BWT), all possessing high tolerance levels to P. solanacearum, are jointly released by the ARS/USDA and the Univ. of Georgia.