Whatis Ecoli
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dnaوساختار کلی(زبان اصلی)
RNA with its nitrogenous bases to the left and DNA to the right.
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Peach Leaf-Curl
Peach Leaf-Curl
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| Agdex#: | 212/634 |
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| Publication Date: | 10/83 |
| Order#: | 83-071 |
| Last Reviewed: | 10/83 |
| History: | Not Available |
| Written by: | WP Roberts - OMAF |
Table of Contents
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مقاله زبان اصلی
This important disease of rice is very widespread in Arkansas, easily found in 50-66% of rice fields randomly surveyed in 1993 and 1994 and at damaging levels in most long term rice fields growing highly susceptible semidwarf long grain rice varieties. Actual yield loss to sheath blight appears to have lessened somewhat the past decade with the development of more tolerant varieties and improved cultural practices employed by many farmers, however, yield losses of 5-15% are still fairly common in many fields. Losses of 50% and greater, reported in the 1980's on Lebonnet and other very susceptible varieties, are now only rarely observed and are confined to smaller areas of fields. Before 1970, sheath blight was only a curiosity in Arkansas, but with the introduction of shorter and more susceptible varieties during the 1970's -1980's, the increased use of nitrogen fertilizer for higher grain yields on these varieties, alternate year rice rotations, and reduced tillage practices, sheath blight rapidly became the most widely established rice disease in the state. Sheath blight is more consistent but much less dramatic than blast, causing routine problems and losses in many fields each year. Weather can affect the severity of the disease with hot, humid years like 1991, 1993, and 1995 resulting in greater damage state-wide than years with cooler summers like 1992, 1994, and 1996.
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