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What quality indicators must pear nursery stock meet when leaving the nursery?
Pear nursery stock grading indicators Grade Item Grade 1 Grade 2 Cultivar and rootstock type Pure and true Roots Number of lateral roots More than 4 More than 3 Main root length More than 10 cm Lateral root length Not shorter than 15 cm, spreading Stem Rootstock stem section length Less than 10 cm Height More than 130 cm More than 100 cm Thickness (at 5-10 cm above ground) More than 1.2 cm More than 1 cm Rootstock treatment The rootstock stub must be cut off, the rootstock has no injury Union healing degree Completely healed Number of plump buds within the shaping zone More than 6 Note: Annual nursery stock yield per hectare below 150,000 plants. In the Beijing area, the pear rootstock should be Pyrus betulifolia or Pyrus ussuriensis.
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What are the specific appearance grade indicators for pear fruit?
Pear appearance grade specification indicator items: Special grade, Grade 1, Grade 2. Basic requirements: fully developed, mature, fruit intact and good, fresh and clean, no off-flavor, no abnormal external moisture, no puncture wounds, no insect-damaged fruit and no disease. Color: has the color that this variety should have when mature. Single fruit weight (g): the single fruit weight grade requirements for major pear varieties are shown in Appendix A (normative appendix). Fruit shape: regular, relatively regular, may have defects, but no deformed fruit. Fruit surface defects: 1) Bruising and compression injury: none, none, slight bruising and compression injury allowed, area less than 0.5 cm2. 2) Abrasion injury: allowed area less than 0.5 cm
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What are the indicators for judging frost damage in citrus?
Citrus frost damage is a major disaster in citrus production in China, and it is especially a major threat to citrus production in the middle and lower reaches of the Yangtze River and areas to the north. Large fluctuations in citrus yields are often directly related to low-temperature frost damage during the overwintering period. The meteorological indicators of citrus frost damage, classified by the degree of occurrence, can be divided into -5...
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